EPA-600/2-76-263
December 1976
Environmental Protection Technology Series
A RIGID, PERFORATED PLATE
OIL BOOM FOR HIGH CURRENTS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/2-76-263
December 1976
A RIGID, PERFORATED PLATE OIL BOOM
FOR HIGH CURRENTS
R. R. Ayers
Shell Development Company
Houston, Texas 77035
68-03-0331
Project Officer
John S. Farlow
Oil and Hazardous Materials Spills Branch (Edison, N.J.)
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Industrial Environmental
Research LaboratoryCincinnati, Ohio, U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
ii
-------
FOREWORD
When energy and material resources are extracted, processed, con-
verted, and used, the related pollutional impacts on our environment
and even on our health often require that new and increasingly more
efficient pollution control methods be used. The Industrial Environy
mental Research Laboratory - Cincinnati (lERL-Ci) assists in develop-
ing and demonstrating new and improved methodologies that will meet
these needs both efficiently and economically.
This report describes an improved boom capable of directing spills
of oil or floating hazardous materials toward shore in a 3-knot (1.5
m/s) river or tidal current. This capability is about double that of
conventional booms. The applied research leading to its development
and the confirming tests of its capability at EPA's OHMSETT facility
are also described. Detailed information and construction drawings
are provided to enable anyone with a need to protect high current
streams from spills to build a duplicate boom for their own use, and
to enable researchers with related interests to follow the develop-
mental rationale. For additional information, please contact the
U.S. EPA Oil and Hazardous Materials Spills Branch, Edison, N. J.
08817.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
ixi
-------
ABSTRACT
A boom capable of diverting oil spills toward shore in a 3-knot (1.5 m/s)
river or tidal current has been developed. Loss of No. 2 and No. 4 Fuel Oil
at this velocity is typically less than 15 percent when the angle of the boom
is 45 degrees to the shoreline. In contrast, conventional booms lose this
amount at only 1 knot (0.5 m/s).
Good performance at high currents is achieved by placing a baffle upstream
of a conventional flat plate boom. The baffle, an inclined, perforated plate,
is used to create a flow-sheltered region where the oil layer thickens. A
continuation of the inclined plate baffle forms the "floor" of the sheltered
region to control the flow rate of exiting water. Horizontal plates immedi-
ately behind the baffle reduce water down-flow.
The boom is made up of 8-foot (2.4 m) long, rigid sections similar in
plan view to a floating dock module. The length of the boom depends upon the
number of modules pinned together side by side. Floating suction or sorbent
rope collection devices may be used to remove accumulated oil from the flow
sheltered region and increase "capacity".
One or more modules can also be attached to vessels of opportunity and
used as a skimmer.
Construction drawings are included with this report.
This report was submitted in fulfillment of Program Element No. 1BB041,
Contract Number 68-03-0331 by Shell Development Company under the sponsorship
of the Environmental Protection Agency. Work was completed as of May 1976.
IV
-------
TABLE OF CONTENTS
Foreword
Abstract
List of Tables
List of Figures viii
Acknowledgements x
I. Introduction 1
II. Conclusions 2
III. Recommendations 3
IV. Rigid, Perforated-Plate Boom Design Summary 4
Description 4
Performance in Currents 4
Performance in Waves and Debris 5
Oil Recovery Techniques 5
Applications 17
V. Discussion of the problem 20
The Problem 20
Limitations of Conventional Booms 22
Previous Shell Investigations 30
Investigations of Others 31
VI. Initial Baffle Studies 37
Introduction 37
Summary 40
Stub-Tube Baffle Experiments 40
Perforated-Plate Baffle Experiments 45
Preliminary Tow Tests - Perforated-Plate Boom Concept 45
VII. Confirming Tests 54
Tow Tests - Houston 54
Three-Dimensional Tow Tests - OHMSETT 55
v
-------
TABLE OF CONTENTS (cont'd.)
VIII. References
IX. Appendices
A. Details of stub-tube baffle experiments.
B. Details of perforated-plate baffle experiemnts.
C. Summary of perforated plate tow tests.
D. Three dimensional tow tests - Houston.
E. OHMSETT test facility.
F, Additional test information - OHMSETT tests.
G. English-Metric Conversion table.
VI
-------
LIST OF TABLES
Table Page
1 Perforated Plate Tow Tests 48
2 Two-Dimensional Boom Tow Tests 58
3 Measured Test Oil Properties - Shell Tests 59
4 Measured Test Oil Properties - OHMSETT Tests 63
5 Results - High Current Boom Tests at OHMSETT 64
vii
-------
LIST OF FIGURES
Figure Page
1 Photograph of Boom in EPA OHMSETT Tests 6
2 Photograph of Boom in EPA OHMSETT Tests 7
3 Boom Modules Side by Side 8
4 Four-Foot Wide High Current Boom Test Section 9
5 Profile of the Rigid, Perforated Plate Boom 10
6A EPA High-Current Boom - Plan & Elevation 13
6B EPA High-Current Boom - Bottom Plate & Details 15
7 Predicted Performance of High-Current Boom 11
8 Example of Means to Recover Oil 16
9 Plan View of High Current Boom 18
10 Emergency Self-Propelled Skimmer 18
11 Two Permanent Skimmer Configurations 19
12 Containment and Diversion in River Currents 21
13 Conventional Boom Containing Spilled Oil 23
14 Oil Set-Up in Front of a Barrier 24
15 Minimum Boom Skirt Draft for Containment 26
16 Histogram of Oil Loss from Coast Guard Boom Tow Tests 28
17 Critical Velocity for Oil Loss and Diversion 29
18 First High-Current Boom Model by Shell 30
19 Revised Baffle Concept 32
20 A Preliminary Configuration for Project Sea Dragon 33
viii
-------
LIST OF FIGURES (cont'd)
Figure Page
21 Double-Boom Concept Tested by Atlantic Research Corp. 33
22 Ocean Systems Dynamic Keel Concept 34
23 JBF Fixed Inclined Plane Concept 34
24 Pace Flexible Double Boom Concept 36
25 Initial Baffle Candidates for the Shell Study 38
26 Shell Current Tank Facility 39
27 Optimum Inclined Plate Baffle Boom Arrangement 42
28 Tentative Optimum .Stub-Tube-Baffle Boom Arrangement 43
29 Test Set-Up of Stub-Tube Array in Current Tank 44
30 Photographs of Tow 2-D Test Model (Full Scale) 47
31 Test Configurations 50
32 Final Boom Configuration Before Flotation is Added 53
33 Boom Test Set-Up Houston in Wave/Tow Tank 56
34 Boom Section During Tow Testing 57
35 Sketch of Boom Mooring System Used for OHMSETT Tests 60
IX
-------
ACKNOWLEDGEMENTS
Shell appreciates the opportunity to conduct this interesting
project for the EPA. For his helpful advice during the program and his
assistance in reviewing the draft manuscripts, we thank Mr. John S. Farlow,
Project Officer.
To our valuable technicians, Jim Smith, Dean Henning, and Bob
Hammond, who made the prototype work well, we also offer thanks.
x
-------
I. INTRODUCTION
The most effective way of controlling the movement of oil spilled
on water is to use floating oil barriers, or booms. Although booms have
been significantly improved in recent years, a fundamental problem re-
mains in containing and diverting oil in high currents. Many of our
rivers and tidal estuaries have currents in excess of two knots and con-
ventional booms do not perform well at such velocities.
A radically different rigid, modular boom has been designed and
verified by test for permanent installation in high currents. The design
is based upon placing a baffle immediately upstream of a barrier to slow
down the surface flow and, as a consequence, contain oil between at
higher currents than conventional booms.
-------
II. CONCLUSIONS
1. A high-current boom capable of diverting No. 2 and No. 4 fuel oil to shore
at 3 knots (1.5 m/s) with typically less than 15 percent of the applied
oil loss under the boom has been developed by Shell with funding from the
U.S. Environmental Protection Agency (EPA).
2. This boom design depends upon an inclined, 50 percent perforated-plate
baffle just upstream of a solid vertical-plate barrier. The flow-sheltered
region between the baffle and the barrier has a perforated plate as a
bottom, slowing the exiting water. In addition, horizontal flow control
plates immediately behind the inclined baffle reduce water downflow and
minimize turbulence.
3. The boom profile is built into 8-foot (2.4 m) wide rigid sections and
linked together like a floating marina dock.
4. A primary application for this high-current device is its use as a perma-
nently deployed diversionary boom, perhaps downstream of an oil loading/
unloading dock. A standard skimmer, used in the flow-sheltered region of
the boom to recover oil accumulated, will increase the boom's effectiveness.
5. Boom modules can be attached to vessels of opportunity for use as a tempo-
rary emergency skimmer. They can also be placed in a specially designed
vessel and used as a permanent inshore skimmer.
6. The boom design is based on extensive full-scale experimentation and test-
ing at the Shell current and wave tanks. Principal confirming tests were
conducted at the EPA's OHMSETT Facility.
-------
Ill. RECOMMENDATIONS
1. A single boom module should be fabricated according to the field-type
design resulting from this program. The module, a "heavy-duty" version
of that testfed, should be tow-tank tested to make a final check of the
flotation/weight and adequacy of the design (Figures 6a and 6b). Minor
corrections should be made if needed.
2. Additional modules should then be fabricated and installed (pinned together
to obtain the total length needed) in at least one suitable field location
where boom performance can be evaluated in a real-life situation.
-------
IV. RIGID, PERFORATED-PLATE BOOM DESIGN SUMMARY
DESCRIPTION
The forty-foot-long high-current boom section shown during tank testing
in Figures 1 and 2 is a major result of a development program conducted by
the Pipeline Research and Development Laboratory of Shell Development Company
for the Industrial Environmental Research Laboratory of the U. S. Environmen-
tal Protection Agency under Contract Number 68-03-0331.
The rigid boom is formed by joining modules side-by-side (Figure 3). A
typical four-foot wide module is shown in Figure 4. Design features are
revealed in Figure 5. Upstream of a conventional flat-plate barrier the
design incorporates a perforated-plate baffle to absorb part of the kinetic
energy of water flow that a barrier alone normally experiences. A reduced-
velocity region is created between the upstream perforated plate baffle and
the downstream barrier. In a 3-knot (See English-Metric Conversion Table,
Appendix G) free-stream current, for instance, currents of less than 0.6
knots have been measured in the reduced velocity region. Because loss of oil
past a barrier is a function of the local velocity, oil does not easily
escape under this barrier.
Streamlined flotation incorporated in the forward part of the profile
and flotation aft of the rear barrier combine to achieve the proper still-
water alignment of the boom. A planing, perforated bow adds to the dynamic
stability of the boom in combined waves and currents. Approaching oil read-
ily enters the 50 percent open-area bow and flows into the reduced velocity
region, rather than escaping under the boom. Once inside the reduced-
velocity region, oil thickens to facilitate removal operations. Contained
water exhausts downward through a 20 percent open-bottom closure plate.
PERFORMANCE IN CURRENTS
Based on extensive full-scale testing both at Shell's wave-tow tank in
Houston, Texas and EPA's OHMSETT facility in Leonardo, New Jersey, we recom-
mend the design summarized in Figure 6 for field applications. This design
differs from that tested only in strength, durability and handleability con-
siderations.
Figure 7 contains performance data for a high-current boom based on se-
lected tank test results. In certain cases extrapolations are made to cover
a larger range of spilled oils. More detailed results are included in Sec-
tion VII.
-------
The final design evolved from a careful analysis using flow diffusion
and boom diversion principles to enhance the control of spilled oil in high
currents. Initially two specific flow diffusion concepts were investigated:
an inclined, perforated plate baffle and a stub-tube array baffle. In
the experimental program each concept was evaluated and systematic alter-
ations were made reflecting what was learned from previous tests. This
interactive "feedback" process yielded somewhat optimized configurations
for the two concepts. The inclined, perforated plate baffle - quite
different looking from the initial concept - proved to be the better
baffle-boom of the two for high currents. Descriptions of these basic
experimental studies are found in Section VI.
PERFORMANCE IN WAVES AND DEBRIS
Test data described in Section VI indicate that small choppy waves,
having periods of up to 2 seconds have only minor effect on the percent-
age of oil lost. Short waves (with the exception of those 10-foot long
waves which excite the boom's natural frequency) impact the boom, and the
boom responds like a breakwater, creating a much calmer area within the
quiet region of the boom and behind it. In wave periods longer than 2
seconds, the boom will tend to follow the water surface like a boat, be-
ing limited by the freedom of motion of the connections when the direction
of wave propagation is not normal to the boom. This boom is best suited
for permanent service in waters where waves are generally less than 1 foot
high.
The high-current boom is designed to allow current-borne debris to
slide past underneath. Nevertheless, we expect that buoyant debris will
accumulate in front of the boom. This debris must be cleared either by
manual removal or by opening the boom to allow debris to pass on. The
sturdy boom design plus spring-like cable moorings should avoid damage
from debris collisions with the boom.
OIL RECOVERY TECHNIQUES
Oil transported by fast-moving waters and diverted shoreward by the
high-current boom accumulates rapidly. Means must be provided in a
typical field installation to rapidly recover oil as it accumulates.
The high-current boom is compatible with virtually any type of skim-
mer that will fit within it. For light oils it is appropriate to use a
floating suction skimmer. There are a variety of floating suction skimmers
that can be used with this boom. Additionally, Shell has developed one
for other purposes (1) that is also suitable for this application.
Adsorbent belts - because of the nature of oil adhesion - work better
on more viscous oils such as Bunker "C". An example is the mop-like
adsorbent rope belt shown in Figure 8. The rope belt is operated in a
closed-loop fashion inside the entire length of boom and oil is wrung
from the belt and recovered at the shore.
-------
FIGURE 1 - TESTING IN WAVES WITH NO. 2 FUEL OIL AT OHMSETT
-------
FIGURE 2 - TESTING IN WAVES WITH NO. 2 FUEL OIL AT OHMSETT
-------
FIGURE 3 - TEN MODULES JOINED TO MAKE ONE RIGID SECTION OF BOOM
(SHOWN FLOATING IN A RESTING POSITION - NO CURRENT
AND NO WAVES)
-------
FIGURE 4 - FOUR-FOOT-WIDE HIGH CURRENT BOOM TEST SECTION
-------
FORWARD
AFT
4-1/2'f*
dx_^ ^*_^
o o
o o
0.0.0
(50% Open)
2" diam.
FIGURE 5 - PROFILE OF THE RIGID, PERFORATED PLATE BOOM
-------
NOTE: Figure 6 on pages 12-15.
o
:*:
o
U
O
OJ
ro
O
5-
O
15 30 45
Diversion Angle, 0, Deg.
60
FIGURE 7 - PREDICTED PERFORMANCE OF HIGH-CURRENT BOOM WITH LESS
THAN 10% OIL LOSS. BASED ON FULL SCALE TEST RESULTS
(p = 0.89) AND FROUDE NUMBER SCALING FOR OTHER p 'S
11
-------
LE.MSTH qlER_A,V.l.
12
-------
TUBE FRAMES
UPPER FLOAT SUPPORT ife
DA HXHO60LT
ORES. ^Vl' L6. WITH
V HX CRES SELF LOCK NUT
SEE ELE\/
'ft PIM
LIUK, W.LM CHAIM AST I? 1C,
WTH V4" ^ CRfS. ROD STAPLE
TO PlUlE. VJE.LO E.UD OF AL CHAIN TO
TUBE FRAME OMIT OWE SIDE
Okl EMO FRAME _
CRES ROO
S'/B
EWD FRAME AS NlOTED
i fe UPPER FLOW
5£M WEIO ROD LSWJO FLUSH
DETAIL->
" BT 8TM
3-REQ'D SEE OETAIl-E
fe'sTFRflUT ife STlHr'UH
SEE DETAIL-F
_ti" 1 | FUJI I
H>TM FLOAJ |
i'
I ALL MATERIAL TO bE AUM
&0&I-TS,-H-IH UWLE&S UOTED.
7.
TO &E STAJMUE&5 T-f. io3.
5 AUTvlfet FRAME JOIMTS TO E)6
SEAL WELD6D WATERTIGHT.
4 REMOVE ALL ROU&H EDGES'.
APTEP- FAfcRlCATIOM AL\.
SURFACES To fee COATED
DEv/oe-RE
-------
14
-------
6T 6A.R CRE6
DRILL t-TAP FOR
WNW6L.OLESS
THREADED
SPOT WELD IB STtA
tfe OR RWET
_ PET/ML-
feOTTONA 5-TlFFEKlERt
SPOT WELD OR Rll/ET
FROklT ife STIFFtJR
_ DETML-S
* .
UPR. FLOftJ SUPPORT B
MIL R 400 SIM 10 MLBC MR*. CQ OR EAOM.
At>«ESWE IN ACCOROAM
A,RR6'T iHOWM FOR
FRAMES- OWT OM OME SIDE Of EMO
» V IW5ERT IWWTf OF
6TW SLOTS FOR jTQW *Wi
50?° OPESl itf D^ HOUS -
BEMD UP 30° PITCH _ ;_
~CUT S.V1ELDTO FIOKV *
FWD
SHOWKJ EXPANJDED
FIGURE 6B - EPA HIGH-CURRENT BOOM - BOTTOM PIATE AND DETAILS
15
-------
NOTE: Figure 7 on page 11.
-Tail Pulley
Mooring
Lines
Piling
Typ-
Perforated Plate Boom
(7 Modules Shown)
Adsorbent Rope Belt
Wringer/Drive
Adsorbent Rope Belt Skimmer
FIGURE 8 - EXAMPLE OF MEANS TO RECOVER OIL
16
-------
APPLICATIONS
Diversionary Boom. This most obvious application for the high-current
boom is downstream from oil loading/unloading docks. Figure 9 shows a typical
permanent installation of this type. The design of the boom installation near
a shoreline will differ depending on the shoreline topography and other consid-
erations. It is essential, however, that skimmers be available to rapidly
recover oil as it is diverted shoreward. The mooring system design should
include a power winch to allow easy opening of the boom to free debris accumu-
lations. The design should also include "weak links" in the moorings to allow
the boom to break free and string downstream in the event of excessive flood
water currents or collisions with large floating objects.
Boom modules are also designed for truck transport to a spill location
and the joining process is quick and simple, permitting their use on an ad hoc
basis in a spill emergency.
Emergency Self-Propelled Skimmer. Another useful application of the high-
current boom design is to make a skimmer from an ordinary work vessel or fish-
ing vessel in an emergency. A configureation of this type is sketched in
Figure 10. Of course adaptive elements are required in attaching the boom to
the vessel of convenience. Truck transport of boom modules for this purpose
is warranted by the predicted performance.
Inshore Skimmer. If supported by a vessel having a "U" shaped bow, or by
a very small and shallow draft barge, module(s) can be used as a sweep skim-
ming device for inshore waters. Two possible configurations are shown in
Figures lla and lib.
17
-------
Flow
Bank
Pi1i ng
Mooring Line
High-Current Boom
FIGURE 9 - PLAN VIEW OF HIGH-CURRENT BOOM IN
DIVERSIONARY CONFIGURATION
Vess
Pump
2 High-Current
Boom Modules
Skimmer
Transition Element
Storage
FIGURE 10 - EMERGENCY SELF-PROPELLED SKIMMER USING RIGID,
PERFORATED-PLATE BOOM MODULES
18
-------
Flow
Bow
Stern
Flow
Rigid Boom Module
Floating Suction
Skimmer
Skimming
Vessel
Bow
O)0
a) Monohull Vessel With Permanent Storage
Boom
Module
Stern
Deck
Tie (Typ.)
Skimmer
Pontoon
(Typ.)
Outbd. motor
Deck
To Towable Bag
b) Catamaran Vessel With Towable Bag Storage
FIGURE 11 - TWO PERMANENT SKIMMER CONFIGURATIONS USING RIGID BOOM MODULES
-------
V. DISCUSSION OF THE -PROBLEM
THE PROBLEM
Historically and presently the most effective way of controlling the
movement of oil spilled on water is to use floating oil barriers. At pre-
sent there are over 80 different commercailly available oil spill barriers,
or booms. In recent years significant improvements have been made in the
basic oil boom design: They include increasing the boom freeboard to mini-
mize oil splashover in waves, enhancing boom flexibility to allow wave com-
pliance, improving boom strength and stability in currents and making design
changes to facilitate handling, deployment, cleaning and storing.
In spite of these improvements in design, however, a fundamental problem
remains in controlling oil with booms in high currents and in steep waves.
This report considers the problem of oil spill control on fast-moving waters
as found in rivers and tidal estuaries. The problem of oil booms in waves is
equally challenging, but one must understand the separate effects of currents
and waves in order to understand their complex interaction.
Analysis of possible clean-up techniques applicable to an oil spill on
fast moving waters makes it clear that the response time is critical. Re-
sponse time is measured from the time a spill is reported to the time clean-
up equipment is mobilized and working. If a spill occurs on a river where
the current is 3 knots (See English-Metric Conversion Table, Appendix G) , for
instance, the oil lens centroid would be approximately 1.7 miles downstream
in 30 minutes, neglecting the effects of wind and spreading. Use of oil
booms for this situation would be limited to the following cases:
(1) Durable permanently-deployed floating booms.
(2) Stored booms ready for immediate deployment at a location down-
stream within response constraints.
(3) Completely portable boom systems capable of being rapidly trans-
ported and deployed at any location.
In most cases it is important to immediately remove oil temporarily con-
tained or diverted by a boom, because oil can be lost by droplet formation
[escaping at current velocities as low as 0.7 knots (2)].
A containment boom is normally fixed at each end and the elongated bar-
rier is allowed to drape in a U-shaped catenary because of current drag
forces. Such a boom configuration is shown in Figure 12a. Oil drifting
toward a boom, if retained, will thicken locally in front of the boom (set-
up), making oil removal feasible. Shell tests (2) have shown that booms of
20
-------
(a) Plan view of containment boom
Flotatio
Weight
Section A-A
Skirt
Deformed Shape
Typical Boom Profile
(Enlarged)
fb) Plan view of diversionary boom
FIGURE 12 - CONTAINMENT AND DIVERSION IN RIVER CURRENTS
21
-------
usual dimensions can allow oil to escape at velocities as low as 0.7 knots,
although under certain conditions oil containment at velocites up to 1.5
knots has been achieved.
A large number of experiments (3,4) directed toward understanding the
various mechanisms of oil failure under a containment boom have generally
revealed that containment is feasible with shallow to moderate draft conven-
tional booms in currents up to 1.5 knots.
One generally accepted analysis (3) of "drawdown" oil losses under a con-
tainment boom indicates that in a 2-1/2 knot current, skirt drafts of 4 to 10
feet are needed for oils having specific gravities of 0.85 to 0.95. Since
drag forces increase as the square of the velocity and linearly with increased
draft, the structural strength and stability of a boom in fast-moving waters
is also of major concern. We conclude that high-current containment using
deep-draft booms is not a viable approach to the problem.
A diversionary boom is moored at an acute angle to the river flow and
shunts oil from the high velocity flow region in the middle to the slower
region near the bank (Figure 12b). The diversionary boom shape has been found
in practice to keep oil from escaping downstream in higher currents than the
containment boom shape. A diversionary boom, however, is difficult to moor
such that every segment of the boom makes the same acute angle with the flow
vector (to afford maximum oil retention). The natural tendency of the boom is
to deform under flow forces as indicated by the dashed line in Figure lOb.
When any portion of the boom is nearly normal to the flow, containment boom
losses can occur. Thus diversion, usually with shallower conventional booms,
offers more promise than containment. But even diversion can be inadequate in
moderately high currents. A more complete discussion of diversion and contain-
ment is contained in the next part of Section V.
Many of our rivers and tidal estuaries have currents in excess of two
knots. Since mere design changes of the conventional boom do not hold prospect
for fast-moving waters, a radically different concept is appropriate. Our
approach is to improve upon the conventional boom profile by adding a baffle
immediately upstream of a boom to slow down the surface flow. Based on test
results such a baffle/boom combination - an unconventional boom profile -
offers effective oil control in higher currents in both containment and diver-
sion applications.
LIMITATIONS OF CONVENTIONAL BOOMS
A conventional boom is shown in Figure 13, as it was used in an oil spill.
The components of a typical boom are sketched in Section A-A of Figure 12.
Although there are differences in the way they are moored, i.e., bottom-
tensioned, top-tensioned, or skirt-tensioned, the loss of oil in each case is
generally determined by the effective boom draft when current forces are
acting (and not the still-water draft). The following is a discussion of the
mechanisms of oil loss for booms used in both containment and diversion. The
normally reported profile of oil accumulated against a barrier is that for a
large contained volume as shown in Figure 14a. Possible failure mechanisms
are entrainment near the headwave (shown) and drawdown near the barrier.
Our specific interest is in small contained volumes because in high currents -
the major concern of this program - rapid, simultaneous oil recovery is
essential.
22
-------
FIGURE 13 - CONVENTIONAL BOOM CONTAINING SPILLED OIL
Figure 12a shows a typical oil boom placed across a river in the contain-
ment configuration. Provided that the set-up oil volume is small (slick
length < 5 times the boom draft), oil loss under a boom is skirt draft sensi-
tive and can be described by the densimetric Froude number:
Fd = V/(gAh) /2 (1)
where
V = Free-stream velocity
g = Acceleration of gravity
A = Fractional density difference,
(pw - P0)/Pw
(p = water density, p = oil density)
h = Barrier draft
Recent Shell tests indicate that the inception of "near-boom" oil loss,
as shown in Figure 14b, occurs when
Fd = 1 (2)
Previously (2) such losses were thought to be independent of skirt draft.
A physical explanation for this failure mode follows: If the contained
oil volume is small, it will accumulate in the wedge of water in front of the
-------
FAR BOOM REGION
NEAR - BOOM ^
REGION
HEADWAVE
FLOW
(a) LARGE VOLUME OIL SET-UP
NEAR-BOOM REGION < 5h
FLOW
(b) SMALL VOLUME OIL SET-UP
FIGURE 14 - OIL SET-UP IN FRONT OF A BARRIER IN A
TWO DIMENSIONAL CURRENT FIELD
24
-------
boom (see Figure 14b) . In this way the set-up lens is protected from the high-
velocity streamlines associated with water flow under the boom. There is
sufficient suction when F, = 1, however, to allow oil to draw down under a
boom. Figure 15 contains curves for the minimum boom draft requirement for
small-volume containment as a function of free-stream current and oil specific
gravity using a 1.0 Froude number.
A second oil loss mechanism associated with droplet formation at the head-
wave is called "entrainment"*. This loss generally occurs in containment with
larger contained oil volumes at about 1 knot. As discussed below, the entrain-
ment mechanism is the probable cause of diversionary losses at moderate
currents. Wicks (2) suggested that droplets will form when the Weber number
based on oil droplet diameter exceeds 22, i.e.,
22
p V2 d
<»>« - -Vi
ow6
where
V = Critical velocity
d = Maximum oil droplet diameter
0 = Oil/water interfacial tension
ow
and other symbols are described previously- Wicks (2) further suggests that
the maximum droplet diameter is given by
Since very few droplets of maximum size are likely to occur, the question
is: "What is the most probable average droplet diameter associated with the
inception of measurable losses?"
Both tests and field experience have suggested that a velocity of 1 knot
is large enough to cause diesel oil loss by entrainment. The sudden failure
which occurs with large contained volumes at currents in excess of 1 knot is
illustrated by data in Figure 16 from offshore oil boom tests by the U. S.
Coast Guard. (5) The test oil in this case was soybean oil.
One can estimate the effective droplet diameter consistent with Equations
(3) and (4) by assuming for light oils such as diesel fuel oil in fresh water:
* In this duscussion "drawdown" implies oil losses are sensitive to skirt
draft and thus dependent on the densimetric Froude number. "Entrainment"
implies no skirt draft dependence and is governed by the Weber number. Both
types of losses look like droplet failure.
25
-------
-------
Vcr = 1 knot =1.69 fps
a =30 dyne/cm = .0021 Ib/ft
ow J
PQ = 0.85 g/cc = 53.07 Ib/ft3
p = 1.0 g/cc = 62.43 Ib/ft3
g = 32.2 ft/sec3
Using Equation (3)
22 a g
ow 6
deff = pV2 = °'0083 ft or °-1 lnch
w cr
And from Equation (4)
d = 0.565 inch
o
Thus
-~- = 0.18 (5)
o
If we further assume that Equation (5) is approximately true for all oils,
then the conditions for entrainment failure are quantifiable.
A diversion boom placed to divert oil to shore in a river was shown pre-
viously in Figure 12b. Because test results suggest that deep-draft booms do
not divert oil better than shallower ones, we suspect entrainment to be the
governing failure mechanism in diversion.
The only required modification to Equations (3) - (5) is to substitute
the normal (to the boom) component of the free-stream velocity for the free-
stream velocity. Then, for diversion
22 a g
f,.
(6)
cr ~ p d
*w eff
and, as before
The predictions of Equations (6) and (7) are plotted in Figure 17 as a
function of diversionary angle. For a No. 2 Fuel Oil spill, for instance, a
conventional boom - if stable and carefully moored - will successfully divert
oil at a diversionary angle of 60° in currents up to 1.5 knots.
27
-------
O)
Width in Fet
>K-450
1200
1300 1400 1500 1600
Pacific Standard Time - Hours
FIGURE 16 - HISTOGRAM OF OIL LOSS FROM COAST
GUARD BOOM TOW TESTS (FROM REFERENCE 11)
28
-------
2.0
VI
4->
o
o
O)
>
o
r
4->
£
O
1.5
1.0
.5
15
30 45 60
Diversion Angle, 9, Degrees
75
FIGURE 17 - CRITICAL VELOCITY FOR OIL LOSS IN DIVERSION
29
-------
PREVIOUS SHELL INVESTIGATIONS
Late in 1969 Shell found means for containing oil at a current velocity
in excess of that found for conventional booms (Figure 18). The technique
used was to alter the near-boom region (compare with Figure 14b) to prevent
premature oil drawdown when small oil quantities are set up. The boom section
tested in 1969 could be considered a special case of a general means for
creating a quiescent pond by diffusing the fluid flow. This was accomplished
by placing baffles (the vertical net and the horizontal lower perforated mem-
brane in Figure 18) in front of a conventional barrier. The downstream length-
to-draft ratio of the profile tested in our laboratory current tank is 4.5,
meaning that the upstream face is close to the streamline separation point for
a conventional barrier in potential flow- We found that:
1. When small quantities of oil were placed between the upstream and
downstream floats, the critical velocity was increased from 0.7
knots for a conventional barrier to 1.4 knots for the test profile
a two-fold increase in containment velocity.
2. When oil was placed upstream of the boom profile the oil entered
the upstream net. But upon passing through the net, the oil lens
broke into many small droplets. The entrained droplets were then
lost through the bottom membrane at velocities between 0.7 and
1.4 knots.
Float
(Possibly Pervious)
FLOW
Screen
Bottom Membrane ^
(With Holes)
FIGURE 18 - FIRST HIGH-CURRENT BOOM MODEL BY SHELL
The conclusion drawn from the exploratory tests is that although the un-
conventional profile had the capability of doubling the containment capacity
of a conventional boom, an alternative to the forward net baffle must be found
to overcome the oil entrainment problem.
The basic principle of artificially creating a quiescent pond to allow
oil to set up in a relatively thick lens is generally accepted today as a
valid technique.
30
-------
Recognizing that the fundamental process involved in creating an artifi-
cial quiescent pond is flow diffusion and that the forward oil entry region
must be a relatively open configuration, a suitable alternative was devised.
In further tests of the flow diffusion principle a forward baffle was formed
using a bundle of short parallel tubes (with center-lines parallel to the flow
vector) and a lower submerged baffle to replace the previous net and by using
an open-bottomed "Coke box" grid to replace the lower porous membrane. The
revised test section, shown in Figure 19, was found to eliminate oil entrain-
ment problems observed in tests of the earlier model using a net.
As seen in Figure 19 the improved boom profile has a more lengthy upstream
to downstream "boom profile" dimension than a conventional boom, somewhat like
a skimmer. The flow diffusion principle, of course, is also applicable to
skimmer configurations. Since it would be quite difficult to develop a flexi-
ble elongate boom with such a complicated cross-section, in earlier development
programs we decided to change the original boom concept into a flow-diffusing
baffle system for a sweep-type oil skimmer. Early in 1972 a prototype inshore
sweep skimming system incorporating flow diffusing baffles was designed and
fabricated (1). Investigations revealed that flow diffusing baffles could be
thought of as flow energy absorbing baffles, the idea being to extract the
maximum flow energy from the relative water velocity while at the same time
endeavoring to minimize oil entrainment caused by excessive turbulence. The
baffle systems used in developing the skimmer were incorporated directly,
without attempting to optimize the configuration.
This report describes using flow-diffusing techniques to design a high-
current boom.-
INVESTIGATIONS OF OTHERS
Early in 1970 the Garrett Corporation (6) conducted tests on a "quiescent
pond" baffle arrangement for use in a proposed skimmer arrangement for use in
the API-sponsored Sea Dragon offshore skimming system. The baffle system that
Garrett tested as a skimmer can be equally considered as a two-dimensional
unconventional boom profile. Figure 20 shows one configuration applicable to
a boom design that they evaluated. It includes a forward spillway and bottom
louvers. Garrett model tests proved that the combined forward and submerged
lower baffle systems of their design were essential to the effectiveness of
the quiescent pond. They did not, however, have an effective forward baffle
arrangement for minimizing bow turbulence effects in waves.
Early in 1971, Atlantic Research Corporation (3) found that a bottomless
double boom arrangement had greater velocity capability for oil retention than
that of a conventional boom. Their investigations revealed that the profile
shown in Figure 21 had a 25% increase in containment capability over that of a
conventional barrier. Important test results are that the forward barrier
must be hydrodynamically shaped to reduce entrainment effects but that a flat-
plate aft barrier is adequate.
In late 1971, Ocean Systems, Inc. (7) tested the unconventional boom con-
figuration shown in Figure 22. The "dynamic keel" 1/3-scale version, having
a width of 2-1/3 feet and a draft of 10 inches, had an oil loss rate of 9% at
0.9 fps (based on the volume of oil applied) and 52.5% at 1.5 fps. This
31
-------
.Side Fins
Rectangular Baffles
A
Fwd Tube Bundle
Oil Accumulation
Area
Plan View
Flow
X X
Section A-A
FIGURE 19 - REVISED BAFFLE CONCEPT
32
-------
Floating Weir
Flow
Forward Section
(Spillway)
Louvered Bottom
FIGURE 20 - A PRELIMINARY CONFIGURATION FOR PROJECT SEA DRAGON
MODEL TESTED BY THE GARRETT CORPORATION
7.0'
Foward
Barrier
Flow
FIGURE 21 - DOUBLE-BOOM CONCEPT TESTED BY
ATLANTIC RESEARCH CORPORATION
33
-------
77'
Forward Slotted Weir
Flow
FIGURE 22 - OCEAN SYSTEMS DYNAMIC KEEL CONCEPT
Inclined Plane
Flow
Gate
FIGURE 23 - JBF FIX^D, INCLINED-PLANE CONCEPT
34
-------
velocity produces smaller densimetric Froude numbers than that for a conven-
tional boom. Their means of scaling these results to larger versions is
unclear.
The JBF Scientific Corporation (8) developed the SHOC, an inverted,
inclined-plane skimmer (See Figure 23), for the EPA. Their concept, although
reasonably effective when used as a skimmer at moderate currents, would pose
problems when used as an unconventional boom at high velocities.
During the test program reported here, the Pace Company (Toronto, Canada)
developed and placed on the market a flexible double boom configuration for
use in fast-moving waters. The boom profile is sketched in Figure 24. Oil
and water enter the forward net section below the forward float; then oil is
accumulated and (some) water passes through the water-permeable aft skirt
section. Sufficient test data are not presently available on this boom.
Finally, a number of different high current control concepts (9,10), some
applicable to both booms and skimmers, are presently in various stages of
development. This research, directed toward controlling oil in 4 to 10-knot
currents, is sponsored by the U.S. Coast Guard and the U.S. Environmental
Protection Agency.
35
-------
Some oil
accumulates
here and moves
along float
in diversion
48"
DOWNSTREAM-FLOAT
Some oil
accumulates here
Flow of Water
('D1 Between 20-28 inches
depending on
current)
Water Porous
Membrane
FIGURE 24 - PACE FLEXIBLE DOUBLE BOOM CONCEPT
36
-------
VI. INITIAL BAFFLE STUDIES
INTRODUCTION
The objective of the initial baffle studies which Shell conducted under
this contract with the EPA was to determine what types of baffles might be
useful for diffusing flow when incorporated in a high-current boom design.
The approach used was to examine and improve two-dimensional models of candi-
date baffles by iterative tests in a closed-loop current tank using PVC beads
to simulate oil. The most successful candidate was subjected to further 2-D
model tests and then tested and modified in a wave/tow tank using oil. A
series of 10 full-scale boom modules were built and tested further under
three-dimensional conditions and finally demonstrated at OHMSETT.
One clear constraint is that a flow diffusing baffle must perform effec-
tively at various diversionary boom angles as well as normal to the flow.
Also baffle candidates should have a relatively shallow draft in order to
improve on conventional containment boom capabilities in fast-moving waters.
Other considerations include lack of debris-fouling problems, wave conformance,
and simplicity of design (hence economy).
Two different baffle configurations were chosen for initial experimenta-
tion. They are the inclined, perforated-plate, and the stub-tube array
baffles shown in Figure 25. Previous Shell investigations indicate that
baffle candidates should have relatively large openings, (as contrasted with
small ones like small mesh nets and screens). Screens cause prolific small-
diameter droplets to form as oil passes through. Droplets sweep under the
barrier before they can recoalesce, causing substantial oil losses. Both of
the candidates have large open-area-to-total-area percentages as indicated in
the figure. Also, both candidates accommodate moderate changes in diversionary
flow angle without significantly changing the flow-baffling capability. One
form of stub-tube array baffle is used in the (API) Open Seas Skimmer
design (1), but that baffle is designed specifically for offshore waves and
is not necessarily optimal for high currents. In this program we have
attempted to optimize the stub-tube baffle primarily for high currents (but
in the presence of river-type waves). The perforated plate baffle, on the
other hand, is likely simpler to construct than the stub-tube one and it
should accommodate debris better.
Our experimental approach was to first study the behavior of a given
baffle in water flow alone. By not using oil, underwater observations were not
clouded and tests could be conducted more quickly and economically. The Shell
Current Tank, shown in Figure 26, was used for this series of experiments.
During tests a reference velocity (upstream from the test section) was contin-
uously recorded using a Marine Advisor's 5-inch (See English-Metric Conversion
Table, Appendix G) Ducted Current Meter. Local velocity readings upstream and
downstream of the baffle array were made using a small A. Ott Kempten Model C-l
37
-------
0 0 ° 0
0 . O _
o o °
O O
0 O
v
o
0
o
o
A,
v
\
LENGTH
SEGMENT
OF BOOM
PLAN
WATER FLOW
PROFILE
(a) STUB TUBE ARRAY BOOM
ooooooooo
ooooooooo
ooooooooo
ooooooooo
v-
PLAN
WATER FLOW
(b) PERFORATED PLATE BOOM
PROFILE
FIGURE 25 - INITIAL BAFFLE CANDIDATES FOR
THE SHELL STUDY
38
-------
FIGURE 26 -- SHELL CURRENT TANK
(GASMER LOCATION)
39
-------
non-ducted propeller-type meter. Revolutions of the propeller per thirty
second interval were electromagnetically counted and the counts were converted
by a linear equation to the velocity in feet per second. Flow directions were
determined using streamers. A qualitative measure of the oil containment
capacity of a baffle-boom profile was obtained by placing sawdust or 0,9
specific gravity PVC beads in the water in front of the device and determining
the approximate quantity accumulated by the device. Of course, the beads do
not simulate the surface properties and viscosity of spilled oils, but they
are rapid and efficient for qualitative testing and do afford a rough measure
of the comparative effect of oil specific gravity on the oil retention capacity
of a baffle-boom combination. Numerous photographs were taken to document the
observations made during the experimental program.
SUMMARY
The perforated plate boom profile shown in Figure 27 has been found to be
better than the stub-tube boom in Figure 28. The choice was based primarily
on the capacity of the two-dimensional boom profiles to retain simulated oil
(0.9 sp. gr. PVC beads). The full scale inclined perforated-plate profile
collected between 90 and 100% of the beads encountered at 2.4 knots. The
stub-tube profile tested at a geometric scale of 78% of full scale, retained
90 to 100% of the beads at a velocity of 1.75 knots. Using an optimistic
scaling law based on the (single fluid) Froude number, the model tests on the
stub-tube profile predict 90 to 100% simulated oil retention at a prototype
velocity of 1.97 knots. Thus the inclined plate profile shows the same
retention capacity at a free-stream velocity 23% greater than for the stub-
tube profile.
Secondary considerations involved in selecting the inclined plate profile
(Figure 27) were the:
1. estimated effect of debris on the profile,
2. ability to design a buoyant upstream structure in which flotation
does not reduce the effectiveness pf the boom,
3. fabrication complexity of the profile, and
4. projected structural adequacy and dynamic stability of the final
boom arrangement.
The design of Figure 27 was later altered based on further tow testing
with oil.
STUB-TUBE BAFFLE EXPERIMENTS (Model Scale)
Various arrays of stub tubes were placed in the test section of the
current tank to explore their capacity to cause a velocity drop while minimiz-
ing turbulence and allowing simulated contaminents (initially sawdust and
later PVC beads) to pass through on the water's surface. Figure 29 shows the
general test set-up used in these experiments. Details of experimental inter-
actions are contained in Appendix A.
40
-------
To explore the effects of scale on the performance of these stub-tube
arrays, several sizes of tubes and spacings were investigated. We assumed
that flow effects would basically scale using the Froude number. This number
is normally utilized in cases of surface-piercing solid objects in a fluid
flow field. Consequently, in Froude scaling, lengths scale geometrically and
velocities scale as the square root of the geometric scale. "Full scale" was
arbitrarily selected as a tube diameter of 1.68 inches.
In the first twelve experimental conditions, called SM (for stub-tube
model) -1 through SM-12, we investigated various tube diameters, orientations,
and array spacings. With arrays having uniform longitudial and transverse
spacings, the pressure drop caused by the baffle was concentrated near the
first three rows. Turbulence was generally intense there and quite calm in
subsequent downstream rows. We increased the spacing of the first two rows to
reduce the local turbulence, but this was to no avail. Perhaps one could
experiment further with altering spacings to a more optimum condition, but we
observed that even a single tube upstream of an array magnified the turbulence
at the front of that array. Then we decided to try means to reduce the venti-
lation phenomenum (air entrained in the water just behind a surface-piercing
tube). Plastic streamers were slipped on an individual tube to make it look
like a surface-piercing symmetrical "wing" shape in order to reduce vortex
formations. This had a beneficial effect on ventilation. Also horizontal
fins (like that used on the submerged leg of an outboard motor) were added.
We observed that with a single tube, ventilation was reduced. The problem is
that the vertical component of turbulence generated is unacceptably high, and
neither the streamer nor the fin reduced it sufficiently to avoid oil loss.
While experimenting with a row of tubes using fins, we noticed that flow
downdraft was less when the row was placed at an upstream or a downstream
angle, rather than vertical. Accordingly, we explored both upstream and down-
stream angular changes to find a condition that produced less severe turbu-
lence. In tests SM-8 through SM-11 we experimented with a "V" shape (in
profile) with the first row of tubes slanting downstream and below and the
second row slanting upstream and below such that the lower ends of the tubes
in both rows formed the base of the "V". Having found a suitable stub-tube
arrangement, we experimented with three different tube diameters, all geomet-
rically similar.
Experiments SM-12 through SM-31 use the same baffle arrangement as was
used in SM-8: By trial and error we chose barrier draft and distance down-
stream of the array, using retention of PVC beads as a basis for selection.
The maximum model velocity for these tests was 3 fps which scales to 4.2 fps
(2.5 knots) if 3.31-inch tubes were used as prototype size. In the last
experiment, SM-31, a horizontal board was placed at mid-draft between the legs
of the first two rows (forming the "V"). This improvement allowed a bead
retention of 93 percent at 3 fps.
At this point the configuration of the stub-tube baffle boom was consi-
dered satisfactory, and the design was frozen. Following similar development
of the perforated plate baffle concept, the two concepts were compared.
41
-------
NJ
IMPERVIOUS BOARDS TO PREVENT VENTILATION
L
FLOW
18.8% OPEN AREA (TYP)
PROFILE
SCALE 1"=16"
OPEN
-------
FLOW
SCALE \n*Q"
3 FINS-SEE
DETAfL "A"
OJ§"
FLOW
PROFILE
0.38"
DETAH. A
(NTS.)
FIGURE 28 - TENTATIVE OPTIMUM STUB TUBE BAFFLE BOOM ARRANGEMENT
BASED ON ONE-HALF SCALE MODEL TESTS
-------
/TANK WALL
FLOW,
TUBE ARRAY
PIPE)
PLYWOOD
SIDE BOARD (TYP)
CM
N-
POSTS FROM ABOVE
TO RESTRAIN SIDE BOARDS
TANK WALL
CURRENT TANK WINDOW
PLAN VIEW
^
+x
1 v"
r
»
,f
PLEXIGLAS WINDOW
f f f T ? /
1
*^
-/
f 10"
I 18
JL DRAFT
SECTION A-A
FIGURE 29 - TEST SETUP OF STUB TUBE ARRAY IN CURRENT
TANK (SIDE BOARDS PREVENT 3D EFFECTS)
44
-------
PERFORATED-PLATE BAFFLE EXPERIMENTS
A second candidate design concept for the high-current boom is the
inclined, perforated-plate baffle shown previously in Figure 27. The initial
choice of baffle geometry for the current tank experiments was a 2-inch-diameter
hole array on a flat plate such that a 46 percent open-area-to-total-area ratio
is obtained. Using two identical plates and sliding one with respect to the
other, open area ratios between 18.8 and 46.0 percent were obtained. These
dimensions are considered "full scale" and not "model" as was the case for the
stub-tube baffles. Because of the uncertainty of scaling laws for the inclined
plate, we decided to test a full scale device. As before, local current
measurements were made to determine velocity reduction and PVC beads were used
to find the bead retention. Details of the trial and error experimentation
are included in Appendix B.
Tests IPM (meaning "inclined plate model") -1 through IPM-13 were con-
ducted using a single perforated plate, sloping below and downstream to
achieve a planing configuration. The open-area ratio, plate inclination and
downstream barrier draft and location were varied systematically. None of the
changes produced an acceptable bead retention at a reference velocity of
3.75 fps, so an additional perforated plate was added to the design.
Then various combinations of plate orientations were tried, including
both upstream and downstream slope angles of both plates. An anti-ventilation
board was placed against the upstream plate at the waterline in some of the
runs. The board had a positive effect in reducing ventilation, but it unfor-
tunately increased bead losses. A Coke-case baffle (Coke case with the bottom
out) was added to the design in an attempt to reduce turbulence (and bead
losses) but this did not work. Finally, a configuration with two planing
parallel plates was found to be promising. But even then fluid downflow
between the two plates caused beads to pull under. The downflow problem was
solved by placing three equidistant (solid) horizontal plates between the
parallel perforated plates. This configuration, regarded as the best of the
33 tests, is shown in Figure 27. With both plates 18.8 percent open and with
an 11-inch barrier downstream, approximately 80 percent of the beads were
retained at 4.8 fps (2.9 knots, Experiment IPM-28). This compares with 93 per-
cent bead retention at a (full scale equivalent) velocity of 4.2 fps (2.5
knots) for the sub-tube baffle (Experiment SM-31).
Since the perforated plate baffle worked well at a velocity of 0.6 fps
(0.4 knot) higher than the sub-tube baffle, tow tank testing was conducted
only with the perforated-plate baffle.
PRELIMINARY TOW TESTS - PERFORATED-PLATE BOOM CONCEPT
After the perforated-plate boom concept was chosen over the stub-tube
boom,the experimental work changed from current tank tests without oil to wave/
tow tank tests with oil. In the initial tow tests the perforated-plate boom
model used in the current tank was fitted with outrigger flotation for towing.
Figure 30 is a photograph of the boom profile, complete with outrigger flota-
tion. The outriggers, of course, are only test fixtures.
45
-------
The initial objective of conducting tow tests on the previously current-
tank-tested model was to find out if the design works as well with test oils
as it did with the oil-simulating PVC beads. A few preliminary tow tests were
run to examine this. We found in a qualitative way that the profile did not
work as well with oil as it did with the beads. Because of this difference in
behavior, we felt that further trial-and-error configuration improvement tests
were warranted.
The first nine tow runs in this period used the configuration shown in
Figure 25. The general test procedures are itemized in Appendix C of this
report. The test oil is a light distillate resembling Number 2 Fuel Oil. Two
types of tests were run: (a) a "constant flow rate" test in which oil is
sprayed on the water in front of the device during a tow run, and (b) a
"constant volume" test in which oil was placed inside the boom initially and
then the boom is towed without applying additional oil.
Summarized test results are shown in Table 1. We found that in the con-
stant volume tests the percentage of oil retained in the sump area of the boom
was about 90 percent. For the constant flow rate test, however, an average oil
retention of about 65 percent was found. This means that a greater percentage
of oil is lost under the device when the oil on the water's surface passes
through the perforated plate toward the sump area. Apparently the oil lost
drains down the front face of the perforated plate rather than passing through
it.
A better boom, we think, is one that has the same percentage oil loss in
both types of tests. Tests 10 and subsequent were conducted to find such a
configuration. After trying various open-area ratios once again (this time
with oil) , various configurations of parallel but spaced-apart horizontal
plate stacks, located between and behind the perforated plates, were tested.
The plates were used to reduce flow downdraft and force oil horizontally
through the perforated plate baffles.
Finally, in Tests 34 and 35 the most satisfactory configuration emerged.
As shown in Figure 31. Configuration G, the design includes no second plate.
Instead, a lower horizontal (and perforated) plate is added just upstream of
the barrier, connecting the lower part of the forward perforated plate to that
of the barrier. This submerged, perforated plate limits the water flow from
the boom; consequently, a more open 46 percent plate could be used. Approxi-
mately 85 percent of the oil applied was retained by this boom at a tow
velocity of 2.5 knots. Figure 32 is a sketch of the preferred perforated-
plate boom configuration before flotation was added.
46
-------
(A) Outrigger flotation attached to the
Inclined plate boom for tow tests.
(B) Photograph showing the test fixture
attached to the front of the boom.
FIGURE 30 - PHOTOGRAPHS OF TOW 2-D TEST MODEL
(FULL SCALE) ( SEE ALSO FIGURE C-l, APPENDIX C)
-------
PERFORATED PLATE TOW TESTS
TABLE 1
Run No.
1
2a)
3a)
4
5
6a)
7a)
8
9
ioa>
lla)
12
13
14a>
15a>
!6a)
17
18
19
20
21
22
23
24
25
26
27i)
281'
29i)
301'
3115
32i)
33i)
34"
35^
361'
371'
Boom
Angle
(deg)
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
%
Plate 1
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
24.5
24.5
46.0
46.0
46.0
46.0
46.0
36.0
18.8
18.8
18.8
18.8
35.0
35.0
18.8
18.8
18.8
18.8
18.8
18.8
46.0
46.0
46.0
46.0
46.0
46.0
46.0
46.0
46.0
Open
Plate 2 or
Bottom Plate
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
31.0
31.0
46.0
46.0
46.0
46. D
18.8
18.8
18.8
18.8
18.8
18.8
18.8
36.0
18.8
18.8
36.0
18,8
18.8
18.8
18.8
24.5
0,
18.8
18.8
18.8
18.8
Tow
Velocity
(knots)
2.53
2.53
2.53
2.53
2.53
2.53
3.07
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
2.53
Oil
Applied
(gal)
3.8
10.0
20.0
3.85
3.75
18.0
18.0
4.5
4.5
10.0
10.0
4.5
4.5
10.0
9.44
4.5
4.5
4.5
4.5
3.82
3.65
4.14
4.03
3.74
3.98
4.09
4.57
4.57
4.20
3.88
4.29
4.52
3.84
5.59
4.27
4.49
Oil Retained
or Diverted
(gal)
1.8
2.0
0.69
0.6
1.98
0.48
1.56
2.38
1.72
1.45
0.56
0.75
1.94
1.02
0.77
2.69
2.63
3.28
2.74
2.77
3.12
3.44
3.95
4.06
3.76
3.44
3.66
3.82
3.28
4.68
3.36
3.52
% Oil
Retained/
Diverted
53b)
__b»c)
89b>
82b'C>
84d>
89d>
97e>
65£>
47f>
__f)
c,g)
62f)
68f>
94C)
92c)
50f)
63f)
__h>
68h)
70
72
79
68 (^
74
78
84
86
89
87
90
85
85
85
84
79
78
Test
Configurations
(see Figure 31)
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
C
D
D
E
E
E
E
E
F
F
F
F
F
F
GJ)
GJ>
Gj)
H
H
48
-------
TABLE 1 (Continued)
NOTES
a) Oil was applied inside the boom prior to towing. This is a "constant
volume test". All other tests were constant flow rate tests.
b) We observed a small oil loss under the forward curtain during deceleration
of boom.
c) We observed a slight oil sheen on the surface after the boom tow run. This
was lost under the boom.
d) We detected only slight losses, less than c.
e) We observed no losses.
f) We observed oil dtoplets surfacing after the run, presumably lost under the
boom. The loss was greater than Note 4, and quite noticeable.
g) This test was run to see if shorter flow control plates would be as effec-
tive as the longer ones used in previous runs. This is to simplify the
design. The shortened plates are used subsequently.
h) A technician rode the skimmer to closely observe the oil loss mechanism.
He saw numerous droplets below the surface inside the boom area. Some of
these droplets passed under the boom, accounting for the loss.
i) Plate 2 was deleted, and a perforated bottom plate was added.
j) This configuration was judged to be the best considering all factors.
49
-------
,Solid Boards to Prevent Ventilation (Typical)
31" / , 43" . 24"
7
17"
r
Flow
(A) For Tests 1 through 9
Plate 1 (Typical)
Flow
Plate with 46% Open Area
(B) For Tests 10 through 18
24"
Flow
(C) For Test 19
FIGURE 31 - TEST CONFIGURATIONS
50
-------
y i
Flow
Configuration (D) for Tests 20 and 21
1 - .
-^__
^ 1
17" 2" (Typ.)^p
1 ==>
'' Plate 2
, ; ^a*^^/
""""""""""fc.
"~"^^u""--»«fc_
"**'^*^» "*^**-i
*^**L^ ~"^^^
/^Bl^^^
"-^'
,
Plate 1
s
i
17"
^-^ 1
^ "
14"
Configuration (E) for Tests 22 through 26
.31".
1 ^^^ /
Uu "t
2" - -:*^
T ^^..^M,,, !
X S.C £. rVCIMVVCU
/ 2 I
.
T
14"
Flow
Plate 1
Perforated Plate
Added
(F) for Tests 27 through 32
FIGURE 31 - (Continued)
51
-------
h- 19"
;PI ate 2 Removed)
2'
Flow
Plate 1
Non-Perforated
(G) For Tests 33 through 35
Plate 2 Removed
i
i
P1OW Perforated
(H) For Tests 36 and 37 (shortened)
FIGURE 31 - (Continued)
52
-------
Four 19-Inch Horizontal Plates
(2-Inch Spacing)
115"
Ln
Flow
46% Open
Area
18.8% Open
Area
FIGURE 32 - FINAL BOOM CONFIGURATION BEFORE FLOTATION IS ADDED (COMPARE WITH FIGURE 31G)
-------
VII. CONFIRMING TESTS
TOW TESTS - HOUSTON
Following the preliminary two-dimensional (2-D) tow tests described in
Section VI, a completely new, self-buoyant test device was fabricated.
Figure 4 shows a photograph of the four-foot wide high-current module. Side-
walls (not shown) seal the sides of the boom for two-dimensional tow testing.
We found it quite difficult to achieve suitable flotation in the leading up-
stream half of the boom. Only streamlined floatation could be used because
flotation having a large projected frontal area would disturb the flow of oil
(and water) into the boom.
The Shell wave tank has an unusual shape, shown in Figure 33. We were
able to achieve a relatively long tow run (100 foot test section) with the
four-foot-wide model, and the results of its tests are not affected by short
test-time problems (as confirmed by OHMSETT tests). However, the tank's
effective length was too short for a 20-foot wide device (Figure D-l), and
the oil losses observed (See Appendix D) were generally less than those found
later during tests at OHMSETT for all tow speeds above 2.0 knots (compare
Tables 2 and 5).
In the 2-D tests at the Shell tank the four-foot-wide boom contained
85.2 percent of a 1.9 mm thick slick of No. 2 Fuel Oil at a 2.94 knot tow
speed. In contrast, a conventional barrier of the same draft contained only
45.9 percent at a 2.25-knot tow speed (see Run Nos. 4 and 8, Table 2). Six-
inch waves reduced the perforated-plate boom containment performance to 64,2
percent from a no-waves containment of 91.0 percent at approximately the
same tow speed (2.28 and 2.35 knots respectively, Runs 1 and 8).
When Navy Special Fuel is used as the test oil, approximately 90 percent
containment effectiveness is achieved at 1.5 knots as compared with approxi-
mately 2.25 knots for No. 2 Fuel Oil (interpolate Runs 15 and 17 and compare
with Runs 1 and 2 respectively). We feel that density (not viscosity) is the
primary reason for the observed difference in containment effectiveness (See
Table 3).
Tests were performed by towing the boom at a constant velocity through a
100-foot long test segment, while applying oil on the water in front at a
constant flow rate. Figure 34 shows the test arrangement. A remotely actu-
ated drop-curtain was attached between the forward ends of the sidewalls.
This curtain was dropped at the conclusion of the tow run to keep oil remain-
ing in the boom at the end of a run separate from that lost under the boom
during a run. Oil losses from the boom were collected and measured after
each run. Detailed procedures were essentially the same as those used in the
preliminary tow tests (See Appendix C).
54
-------
Table 2 contains test conditions and results for 18 tow runs included in
this test set. Table 3 shows the test oil properties. During the first four
tests using No. 2 Fuel Oil, the percentage of oil lost during a run compared
with that applied was less than 15 percent at speeds up to 3 knots, in the
absence of waves. A 6-inch high, 2.8 second period wave increased the loss to
almost 50 percent at 3 knots. Reducing the tow speed to 2.2 knots decreased
the loss to 35 percent in the presence of the wave. If Test 10 is compared
with Tests 1 and 2, we see that the percent loss from the constant volume run
is almost half of that lost from the constant flow rate runs. Thus oil losses
from inside the boom down through the bottom are about the same as those caused
by oncoming oil draining down the upstream face of the boom and underneath.
Tests 12 through 17 were run using Navy Special fuel oil having a specific
gravity of 0.968 at 80°F [No. 2 Fuel Oil has a specific gravity of 0.858 at
this temperature]. Using densimetric Froude number scaling, (Equation (1)),
one can reduce the three-knot effectiveness of the boom with No. 2 Fuel Oil by
the ratio of the square root of oil-water density differences of the two oils
to find an equivalent result for Navy Special oil. The calculated prediction
is that 15 percent of Navy Special oil should be lost at a velocity of about
1.4 knots: Test 17 provides approximate proof of this scaling law. A compari-
son of Run 16 with Run 14 (both at 2.3 knots) shows that losses were evenly
distributed betweep losses under the front face and losses through the sub-
merged perforated bottom for Navy Special oil.
Tests 12 and 13 showed that with the denser Navy Special oil the deleteri-
ous effects of waves (in the 2-D tests particularly) were significant. Later
tests at OHMSETT revealed that waves were not as much of a problem as encoun-
tered in these tests.
Finally, Test 18 was run to show that without the perforated baffle
assembly in front of the downstream barrier, significant oil losses would
occur. Comparing Tests 1 and 18, we see clearly that at about 2.3 knots the
high current boom lost only 9 percent whereas the "baffle-less" boom of the
same draft lost 54 percent of the oil applied.
THREE-DIMENSIONAL TOW TESTS - OHMSETT
The principal confirming tests were conducted at the U.S. EPA's Oil and
Hazardous Materials Simulated Environmental Test Tank (OHMSETT) Facility at
Leonardo, New Jersey". This 65-foot wide tank is 667 feet in length, so that
relatively long test runs - in excess of 90 seconds at 3.5 knots - are possi-
ble. A more detailed summary of OHMSETT is included in Appendix E.
Primary emphasis of the OHMSETT tests of the high-current boom was on
diversionary test runs, since the Shell tank was considered too short for
reliable tests with wide oil control devices.
The objective of the tests was to obtain quantitative oil diversion effi-
ciency data at tow speeds (and hence water currents) of 2.5 knots and above.
A four-foot-long section of high current boom was assembled in a single rigid
module for these tests. Figure 1 shows the boom under tow in the tank during
a typical test run. A sketch of the boom mooring arrangement and overall tank
dimensions is included as Figure 35. The boom profile is identical to that
55
-------
N
Ui
OS
DRIVE
MECHANISM,
TOW WINCH
WAVE ABSORBER
IL APPLICATION NOZZLE
FWD DROP
CURTAIN
Ti i i i i iTi ^ si
OIL STORAGE
FIGURE 33 - BOOM TEST SET-UP HOUSTON IN WAVE/TOW TANK
-------
FIGURE 34 - BOOM SECTION DURING TOW TESTING. SIDE WALLS, FORWARD DROP
CURTAIN AND OIL PIPING ARE ADDED FOR TEST PURPOSES
-------
TWO-DIMENSIONAL BOOM TOW TESTS - FOUR-FOOT WIDE SECTION
TABLE 2
oo
Run
No.
1
2
3
4
5
6
7
8
9
10b)
11
12
13
14
15
16b)
17
Boom
Angle
(dee)
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
Test Oil
No. 2 Fuel Oil
tt
11
It
11
tt
It
It
tt
tl
tt
Navy Special
tt
it
it
ti
tt
Navy Distillate8'
Tow Contact Wave
Velocity, Time f ) Height
(knots) (sec) (in.)d>
2.35
2.39
2.94
2.94
2.99
1,31
2.19
2.28
1.72
2.19
1.69
1.75
2.26
2.28
1.79
2.29
1.37
2.28
-
-
-
-
6"
-
6"
6"
6"
-
6"
6"
6"
-
-
-
-
Oil
Period Applied ,
(sec) (gal.)
19.4
20.7
18.5
16.3
17.2
22.0
19.4
17.0
24.9
16.0
2.17
21.8
19.7
21.1
20.7
16.6
26.9
21.1
Equivalent Oil Retained/
Thickness Diverted
(mm)e> (gals.) %
2.0
2.1
1.9
1.7
1.8
2.2
2.0
1.7
2.5
1.6
2.2
2.2
2.0
2.2
2.1
1.7
2,7
2.1
17.66
18.55
15.76
13.88
8.93
21.78
12.77
10.91
15.96
15.37
17.19
9.60
5.80
8,10
16.55
13.67
24.77
9.68
91.0
89.6
85.2
85.2
51.9
99.0
65.8
64.2
64.1(
96.1
79.2
44.0
29.4
38.4
80.0
82.3
92.1
45.9
a) Detectable loss around sides made this high.
b) "Preloaded" run using 16 gal. oil from previous run. This was run to show
c) Baffles were removed; a straight vertical board was placed at the same 14"
occurred when baffles are not used.
d) Wave steepness, H/L = 1/40.
e) Calculation based on a slick 4 feet wide.
f) Time boom under tow is in contact with test oil.
g) Navy distillate oil has the same properties as No. 2 Fuel Oil.
amount lost through bottom holes.
draft to see how much loss
-------
TABLE 3
MEASURED TEST OIL PROPERTIES
SHELL TESTS
Relationship of;
Surface Properties at 77°F
Oil Type
Navy Special
Fuel Oil
(MIL-F-859E)
No. 2
Fuel Oil
Temp.
(°F)
100
75
50
100
80
60
Specific
Gravity
0.9606
0.9688
0.9722
0.8500
0.8578
0.8653
Viscosity
(cs)
86
201
593
2.7
3.5
4.5
Surface Interfacial
Tension Tension
(dyne/cm) (dyne/cm)
32.4 19.2a)
28.0 27.0c)
Equilibrium
Thickness
(mm)
4.90b)
a) tap water
b) NRL film and tap water
c) distilled water
59
-------
Perforated
Plate Boom
Forward Bridge
t
Bridge
Travel
Aft Bridge
' (Tied to Forward)
FIGURE 35 - SKETCH OF BOOM MOORING SYSTEM USED FOR OHMSETT TESTS
60
-------
shown previously in Figure 4, since ten four-foot-wide segments were bolted
together to form the 40 foot section.
Both containment (90° to the tow direction) and diversion tests (at 45°)
were run at speeds from 2.2 to 3.5 knots. Test oils, described further in
Table 4 were (a) slightly emulsified Sun 75 lube oil and (b) No. 2 Fuel Oil.
The oils were applied at a constant flow rate (with multiple nozzles) on the
water in front of the advancing boom. The approximate run time for each test
was 90 seconds. Additional test information and photos are included as Appen-
dix F.
Efficient diversion (30 percent or less oil loss under or over the boom)
was achieved using the denser Sun 75 oil at a tow speed of 3.5 knots and a
diversionary angle of 45°.
In the containment mode the pitch angle set by the rigging is critical
for highest efficiency. Initial containment tests were completed before a
rigging error was detected. This problem, we believe, accounted for the
boom's flooding at tow speeds above 2.3 knots during these containment tests.
Unfortunately, this problem was not determined in time to permit re-running
the affected tests. Extrapolations to higher velocities can be made, however,
using previously obtained 2-D test data. This rigging error has been corrected
in the final boom design shown in Figure 6.
The OHMSETT test results formed the basis for the projected high-current
boom performance summary shown previously in Figure 5. Extrapolations to oil
types and diversionary angles not tested were made using the generally accepted
densimetric Froude scaling law.
A summary of the test procedures used includes the following steps for a
given tow test:
1. Start the wave generator (if waves are called for).
2. Accelerate the tow bridge and hence the high current boom
to the desired tow speed.
3. Start despensing oil through the nozzles once the boom has
reached a steady-state velocity.
4. Mark the start of the actual test run when oil first reaches
the boom.
5. When the applied oil has contacted the boom for a 90 second
period quickly stop the bridge, hence the boom and hence
the oil losses (if any) under the boom.
6. Then quickly stop the oil application and the wave generator.
7. Manually collect and measure only that oil lost under or over
the boom before it could be diverted. Diverted oil and oil
remaining within the boom at the end of the run are not counted
in the oil loss measurement.
61
-------
8. Record sufficient data to determine (a) the oil application
rate (b) the width of the slick approaching the boom and
(c) the quantity of oil lost in addition to the usual records
of tow speed and wave condition.
In this summary we assume that the boom has been rigged for towing and
that the controlled variable settings have been made. Actual oil losses were
concentrated for skimmer collection using the trailing separating boom (used
to separate oil leaking under the boom from that successfully diverted by
high-current boom) to encircle the lost oil.
A summary of the test results is shown in Table 5. Initially the 40-foot
boom segment was placed at a 45° angle with the tow vector. Using Sun 75 oil,
the first three tests explored the effects of increased velocity on the ability
of the boom to divert oil. At 3.5 knots the diversion effectiveness reduced
to 70 percent, meaning that 30 percent of the applied oil was lost under the
high-current boom. Losses above 30 percent have been arbitrarily selected as
being too high for efficient diversion. At 3 knots the losses were only
5 percent. Tests 4 and 5 indicate that 6-inch, 3 second period waves do not
appreciably affect the diversion effectiveness of the boom. Eight-inch, 2
second waves applied in Test 6 were more choppy than the 6-inch, 3 second
waves and a small reduction in performance is noted.
The boom was rerigged to allow towing at a 90° diversion angle (contain-
ment mode) and additional tests with Sun 75 oil were run. During an aborted
test run (not included in the table) in which the oil application pump stopped
midway into the run, the boom began to submerge. Poorly rigged cable
moorings - the more likely candidate to cause the bow to dip and accumulate
more water than can be relieved through the bottom perforations of the boom - -
were not suspected. Consequently the test program proceeded, and the two 90°
tests (Tests 7 and 8) were run at reduced velocities to avoid boom submergence.
At 2.3 knots, the limiting velocity to avoid submergence, 84 percent of the
oil was successfully retained by the boom. Assuming that the normal component
of velocity to the boom caused the oil loss, one can use the Test 3 results at
45° to predict a 70 percent oil retention at 2.5 knots at 90°. This prediction
is further substantuated by referring to Table 2 which contains earlier 2-D
test results conducted in Houston. In that table the oil loss results for the
first four tests suggest that 90 percent retention capability should be
expected at speeds above 2.3 knots. The percentages shown in Tables 2 and 5
differ slightly because the Houston test runs were shorter and less oil was
lost during the runs. Also Table 2 shows that the same boom profile as used
in these tests was successfully tested in Houston at 3 knots - but the test
rigging there did not cause the boom to submerge.
Test 9 revealed that a 6-inch, 3 second wave did not alter the boom per-
formance at about the same tow speed. An 8-inch, 2 second wave was not tested
on the 90° boom because the boom's dimensions were such that it resonated.
The last two test runs were made using No. 2 Fuel oil as the test oil and
arranging the boom to a 45° diversion angle. The diversion effectiveness in
these tests was about the same as that obtained earlier with the Sun 75 oil.
This result is not surprising because the specific gravities of the two oils
are almost the same (Sun 75 oil is much more viscous than fuel oil, however).
62
-------
TABLE 4
MEASURED TEST OIL PROPERTIES
OHMSETT TESTS
Relationship of:
Surface Properties at 88°F
Oil Type
Sunvis 75
(8 to 9%
water)
No. 2
Fuel Oil
(5% water)
Temp.
(°F)
80
60
80
60
Specific
Gravity
0.9030
0.9111
0,8470
0.8480
Viscosity
(cs)
317
578
7.1
8.9
Surface
Tension
(dyne/ cm)
30.8
28.8b)
Interfacial
Tension
(dyne/cm)
I3.8a)
13.6a'b)
Equilibrium
Thickness
(mm)
a) salt water
b) at 80°F
63
-------
HIGH CURRENT BOOM TESTS AT OHMSETT
TABLE 5
RESULTS
Run
No.
1
2
3
4
5
6
7e)
8e)
9
10
Boom
Angle3) Test
(deg.) Oil
45 Sun 75
45 "
45
45
45
45
90
90
45 No. 2
45 No. 2
Tow
Velocity
(knots)
2.0
3.0
3.5
2.5
3.25
3.0
2.3
2.2
3.0
3.0
Contact
Timeb'
(sec)
75
54
60
60
60
60
60
60
60
60
Wave
Height Period
(ins) (sec)
-
-
-
6
6
8
-
6
-
8
-
-
-
3
3
2
-
3
-
2
Oil
Applied
(gal)
194
208
381
280
299
300
371
339
404
427
Equivalent
Thickness0*
(mm)
1.0
0.8
0.9
0.9
0.9
0.9
1.6
1.6
1.5
1.4
Oil Retained
or Diverted
(gal)
»
i
-
265
263
257
264
214
284
-
-
«iood)
90d)
70
94
86
88
85
84
87d)
85d)
Footnotes:
a) Angle is between boom and tank sidewall.
b) Time boom under tow is in contact with test oil.
c) Based on 30-foot slick width.
d) Estimated.
e) Rotating mooring cables caused boom to pitch downward, then the increased flow submerged the
stern at speeds in excess of 2.3 knots. This can be easily corrected.
-------
VIII. REFERENCES
1. Ayers, R. R. , "Developing An Open Seas Skimmer", prepared by Shell
Development Company for the American Petroleum Institute, Final Report
Contract No. OS-5C, May, 1975.
2. Wicks, M., "Fluid Dynamics of Floating Oil Containment by Mechanical
Barriers in the Presence of Water Currents", presented at API-FWPCA
Joint Conference on Prevention and Control of Oil Spills, New York,
December, 1969.
3. "Concept Development of a Heavy Duty Oil Containment System for Use on
the High Seas. Volume I", prepared by Atlantic Research Corporation for
the U. S. Coast Guard, Contract DOT-CG-00-492-A, Final Report, January,
1971.
4. Houser, J. R., Editor, "Lightweight Oil Containment System - Low Tension
Barrier System", prepared by Wilson Industries, Inc. for the U.S. Coast
Guard, Part I, Final Report, January, 1971.
5. Miller, E., Lindenmuth, W., and Altmann, R., "Analysis of Lightweight
Oil Containment System Sea Trials", prepared by Hydronautics, Inc. for
the U.S. Coast Guard, Report No. CG-D-22-74, Interim Technical Report,
October, 1973.
6. "Oil Spill Containment and Removal System-A Feasibility Study", prepared
by the Garrett Airesearch Manufacturing Company for American Petroleum
Institute, Project Sea Dragon, Contract No. API OS-5, Final Report,
December, 1970.
7. March, F.A., and Beach, R. L., "High Seas Oil Recovery System", presented
at the API-EPA-USCG Joint Conference on Prevention and Control of Oil
Spills, Washington, D. C., March, 1973.
8. Bianchi, R. A., Farrell, J. H, and Johanson, E. E., "Demonstration of
Fixed and Moving Inclined Plane Oil Skimmers for Collecting Oil Under the
Water Surface", presented at the 1972 Offshore Technology Conference,
Houston, Texas, May, 1972.
9. Jensen, D. S., "U.S. Coast Guard Fast Current Oil Removal System Develop-
ment Program", presented at the 1973 Offshore Technology Conference,
Houston, Texas, May, 1975.
10. Dorrler, J. S., Ayers, R., and Wooten, D. C., "High Current Control of
Floating Oil", 1975 Conference on Prevention and Control of Oil Pollution
Proceedings, San Francisco, California, March 25-27, 1975.
65
-------
APPENDIX A
DETAILS OF STUB-TUBE BAFFLE EXPERIMENTS
(SM-1 through SM-31)
A detailed step-by-step summary of the individual stub-tube model baffle
experiments run in the Shell Current Tank (Figure 26) is found in Table A-l.
Figures A-l and A-2 show the configuration profiles, and Tables A-l (for test
SM-1 through SM-11) and A-2 show the principal dimensions. Figures A-3 through
A-34 are selected photographs taken at various states of experimentation.
66
-------
TABLE A-l
EXPERIHENTS WITH STUB TUBE ARRAY
Test
No.
Sl*-l
SM-2
SM-3
SM-4
SM-5
SM-6
Sia-7
No.
Tubes/
No.
Rows
51/6
51/6
51/6
63/8
68/8
42/6
56/8
Size Z X
Tubes Spacing Spacing
Inches Inches Inches
.84 2.0 2.0
.84 2.0 2.0
.84 2.0 3,3,2,2,2
.84 4 (1st row) 4,4,3,3,
2-3/8 (2nd 2,2,2
row)
3 (all
others)
.84 2.0 2.0
.84 2.5 5.0
.84 2.5 2,2,4,5,
5,5,5
X Axis
Y To 1st
Draft Row (j_
Inches Inches
6.0 31.0
6.0 31.0
6.0 31.0
6.0 23.0
6.0 33.0
6.0 30.0
6.0 29.0
Vel.* Ref.d)
Front/Back Vel.
fps fps
1.17/21(1) 1.05
2.26/.60(1) 2.1
2.29/.66(1) 2.1
2.27/61(1) 2.15
2.18/.57(1> 2.15
2.32/.90(3) 2.15
-/- 2.15
A H
Level See
Inches Figure Remarks
1.0 A-3- Look promising, did not
A-5 pull sawdust under (top
observation only) .
1.0 A-6 Increased surface
turbulence .
1.0 Installed glass side and
saw bubbling action, AH
and turbulence.
1.0 Observed turbulence at
1st (3) rows and bub-
bling ventilation action.
1.0 Reduced vortex action
but still lost sawdust
under .
.75 Downstream current did
not decrease as needed,
large amounts of turbu-
lence were observed.
A-21 Vortices still predomi-
nate, hand held tubes
Decision
Look at 2.0 fps.
Increase X-spacings.
Increase spacing of
tubes upstream.
Check original with
8 rows of tubes.
Increase tube spac-
ing.
4 rows 2"(^ , 4 rows
5"q, (SM-7) Alter
spacing to avoid
localities of turbu-
lence at front.
Decided to hand hold
individual tubes
between rows 1 & 2 and
2 & 3 reduced vortex
action.
using metal fins and
streamers to reduce
air ventilation
bubbles and down-
draft flow.
1234
*Vel in front at X = 0, Vel in back at X - 48 , X - 51 , X = 56 , X = 54
Hand held a row of 0.84 inch tubes (2" transverse spacing) in front of seven rows of 0.84 inch tubes (2" spacing both axes):
(a) With 3 fins on each tube of the first row, the turbulence was minimized if the row of tubes was inclined 30° upstream from vertical.
(b) With the row pointing upstream as in (a) a second row of tubes with fins was placed in front using a 25" downstream angle. Turbulence
was reduced but particles became entrapped between the second row of fins an- the first row of vertical tubes. These particles were
caught in an upstream flow.
(c) The current was Increased to 2.4 fps and turbulence increased. After the fins were removed from the second row (with the upstream
angle) the turbulence decreased.
(d) This is measured velocity for the scale model. The equivalent velocity for full scale may be obtained by the formula.
-------
TABLE A-l
EXPERIMENTS WITH STUB TUBE ARRAY (Continued)
Test
No.
No.
Tubes
No.
Rows
Size
Tubes
Inches
Z
Spacing
Inches
X
Spacing
Inches
Y
Draft
Inches
X Axis
To 1st
Row %
Inches
Vel.*
Front/Back
fps
Ref.d>
Vel.
fps
AH
Level
Inches
See
Figure Remarks
Decision
CO
Single Tube Experiments:
Hand held individual tubes to observe water flow:
(a) .84" dia. tube with (1) fin - fin 1" max. under H20 looked good, deeper created Vortices
(b) .84" dia. tube without fin created vortices, upstream angle looked good
(c) .84" dia. tube with streamer - looked good no vortices
Hand held rows 2"(J] (8 tubes each) in front of 7 rows of 2: apart axis of alternating 9 and 8 tubes each 2"
-------
Ho.
Tubes/
Test "No.
No. Rows
Size Z
Tubes Spacing
Inches Inches
X
Spacing
Inches
Y
Draft
Inches
X Axis
To 1st
Row q,
Inches
TABLE A-l
TEST SUMMARY STUB TUBES
Vel.* Ref.
Front/Back Vel.
fps fps
d)
Barrier Location See
X-Inches/Y-Draft Figure
Remarks
Decisions
SM-12 76/9
SM-13 76/9
SM-17 76/9
SM-18 76/9
SM-19 76/9
.84
.84
2.0
2.0
11,4,2,
2? > )
»^>^»^
.84
2.0
.84 2.0
.84 2.0
6.0
6.0
18.0
18.0
-/-
-/-
6.0 18.0
-/-
6.0 18.0
6.0 18.0
-/-
-/-
1.05
1.05
2.0
2.0
2.0
60
72
SM-14
SM-15
SM-16
76/9
76/9
76/9
.84
.84
.84
2
2
2
.0
.0
.0
11
II
(1
6.0
6.0
6.0
18.0
18.0
18.0
-/- 1.
-/- 1.
-/- 1.
05
05
05
69
66
63
4
4
4
60
58
66
1/2-8
2-3
2"-6"
A-29 A 6" draft on bar-
A-30 rier causes forward
currents and turbu-
lence, a 4" draft
decreases action.
A 4" draft causes
forward currents;
and a 2" draft
decreases the
currents.
Upward turbulence
was almost eliminated
at boom.
1" draft of barrier
was too shallow,
2"-8" - No vortices,
but turbulence in-
creased as depth
increased.
A barrier draft of 3"
caused too much tur-
bulence; at 2",
turbulence was
decreased.
Boom draft of 2-8"
caused upward cur-
rents at barrier on
occasions with a 6"
draft causing vorti-
ces to form.
Place barrier further
back.
Move barrier closer.
Increase velocity.
Move barrier closer
to tubes.
Move barrier further
away from tubes.
Go to larger OD P.V.C.
tubes.
-------
TABLE A-l
TEST SUMMARY STUB TUBES (Continued)
Test
No.
No.
Tubes/
No.
Rows
Size
Tubes
Inches
Z
Spacing
Inches
X
Spacing
Inches
Y
Draft
Inches
X Axis
To 1st
Row £
Inches
Vel.*
Front /Back
fps
Ref.d>
Vel.
fps
Barrier Location
X-Inches /Y-Dr af t
See
Figure Remarks
Decisions
SM-20 48/8
SM-21 48/8
SM-22 48/8
SM-23 48/8
1.31 3.0 3.125 9.0 24.0
1.31 3.0 3.125 9.0 24.0
1.31 3.0 3.125 9.0 24.0
1.31 3.0 3.125 9.0 24.0
SM-24 7/9 0.84 2.0
SM-25 76/9 0.84 2.0
SM-26 76/9
1.0 (1st 6.0 20.0
row)
2.0 6.0 20.0
0,84 2.0 2.0 6.0 20.0
2.17
2.17
2.17
4.0
3.9
2.1
2.6
63
75
87
75
64
66
66
4-15
4-10
5-12
3-8
A-31
A-32
Draft of barrier had
very little effect
on surface of H,0.
Did not lose beads
at this setting.
With a boom draft of
10", vortices tried
to form but would not
pull beads under.
At a boom depth of
11-12", forward cur-
rents were created
and should be maxi-
mum depth placement
of boom.
Placing a rear bar-
rier with a draft of
6" at X = 75" caused
severe ventilation
and turbulence.
Placing a 3 to 8"
barrier at X = 64"
caused interference
waves between the
tube array and the
barrier.
Plastic beads of 0.9 Try higher velocity.
specific gravity were
presented and 85%
were retained by the
"boom.
Increase distance
between tubes and
boom.
Move barrier further
away from tubes.
Results not as good
as SM-21. Try con-
figuration of SM-21
at a higher velocity.
Go back to the 0.84"
tube array.
Try even tube spacing.
Approximately 80% of
the beads were re-
tained by the boom.
Vary the barrier
draft.
-------
TABLE A-l
TEST SUMMARY STUB TUBES (Continued)
No. X Axis
Tubes/ Size Z X Y To 1st Vel.* Ref.
Test No. Tubes Spacing Spacing Draft Row 4 Front/Back Vel.
No. Rows Inches Inches Inches Inches Inches fps fps
d)
Barrier Location See
X-Inches/Y-Draft Figure
SM-27
SM-28 54/9 1.31
SM-29
3.0
Same as SM-25
17 (1st 8.25
row)
3.125 (all
others)
Same as SM-28
18.0
SM-30 64/9 1.31 3.0 17 (1st 9.4 18.0
row)
3.125 (all
others)
SM-31
Same as SM-30
3.0 66 3-6 At 3.0 fps and 3"
draft, 60% of the
beads were retained
for separate runs.
2.5 77 8 A-33 With rear barrier at
20" and 8" draft,
90% of beads were
retained.
2.9 77 8 An increase in velo-
city to 2.9 fps
resulted in a reten-
tion percentage of
80.
2.95 81 9 80% of the beads
were retained.
A-34 A single board was
placed horizontally
between the first two
inclined rows of
tubes to eliminate
downward turbulent
flow. Bead retention
was 93%.
Return to the 1.31"
tube array model.
Try higher velocity.
Try deeper draft
tubes and place
barrier further
downstream.
-------
TABLE A-2
TESTS SM-1 THROUGH SM-11:
Use
Figure
A-l configuration and
Table A-l Dimensions
TESTS SM-12 THROUGH SM-31:
Test
No.
SM-12
SM-1 3
SM-14
SM-15
SM-1 6
SM-1 7
SM-18
SM-1 9
SM-20
SM-21
SM-22
SM-23
SM-24
SM-25
SM-26
SM-27
SM-28
SM-29
SM-30
SM-31C
Vel.
FPS
1.05
1.05
1.05
1.05
1.05
2.0
2.0
2.0
2.17
2.17
2.17
4.0
3.9
2.1
2.6
3.0
2.5
2.9
2.95
2.95
In.
18
18
18
18
18
18
18
18
a
a
a
b
20
20
20
20
18
18
18
18
In.
29
29
29
29
29
29
29
29
a
a
a
b
32
32
32
32
35
35
35
35
X3
In.
33
33
33
33
33
33
33
33
24
24
24
24
35
35
35
35
38
38
38
38
x4
In.
45
45
45
45
45
45
45
45
46
46
46
46
47
47
47
47
57
57
57
57
X5 X6
In. In.
60
72
69
66
63
60
58
66
63
75
87
75
64
66
66
66
77
77
81
81
Y4
In.
6
6
6
6
6
6
6
6
9
9
9
9
6
6
6
6
8.25
8.25
9.4
9.4
In?
4
4
4
4
4
l/2"-8"
2"-3"
2"-6"
4"-15"
4"-10"
5"-12"
6
3-8
6
6
3-6
8
8
9
9
a) The tubes for row X were absent in these runs and the row for X_ is
vertical.
b) Inclined tubes were not used.
c) Board placed between X.. and X~ in a horizontal position.
72
-------
TANK WALL
+Z
FLOW
TUBE ARRAY
(PVC PIPE)
PLYWOOD
SIDE BOARD (TYP)
POSTS FROM ABOVE TO
RESTRAIN SIDE BOARDS
CURRENT TANK WINDOW
X
TANK WALL
PLAN VIEW
72"
PLEXI6LAS WINDOW
m
18" DRAFT
PROFILE VIEW ALONG X-AXIS
FIGURE A-l - SKETCH OF STUB-TUBE ARRAY BAFFLE TEST CONFIGURATIONS
FOR TESTS SM-1 THROUGH SM-11. (SIDE BOARDS PREVENT
3D EFFECTS.)
73
-------
96"
*
- *3
L-« x? »-
XT
* ^»l Tnhn"
X5
v V V
- A/
Fins(3ea.)
X6
^^^
Tubes
-
-
I 1
^ *5
T 1
"
Broom
/
x'Sideboard
\^
«^
^C \
24"
Trailing Board
Flow
FIGURE A-2 - SKETCH OF STUB-TUBE BAFFLE TEST CONFIGURATION FOR TESTS
SM-12 THROUGH SM-31. (SIDE BOARDS PREVENT 3D EFFECT)
-------
FIGURE A-3 - SM-1; 1.05 FPS .84" OD TUBES
FIGURE A-4 - TEST SM-1; 1.05 FPS
75
-------
FIGURE A-5 - TEST SM-1; 1.05 FPS
FIGURE A-6 - TEST SM-2; 2.1 FPS
76
-------
FIGURE A-7 - SINGLE TUBE HAND HELD OBSERVATIONS
FIGURE A-8 - SINGLE TUBE UPSTREAM ANGLE (35
1
-------
FIGURE A-9 - SINGLE TUBE WITH FIN 1" DEEP, NO VORTICES
FIGURE A-10 - SINGLE TUBE WITH FIN, TWO INCHES
DEEP, VORTICES APPEARING
-
-------
FIGURE A-11 - SINGLE ROW OF TUBES IN FREE STREAM, VORTICES
FIGURE A-12 - SINGLE ROW OF TUBES WITH STREAMERS, VORTICES
-------
FIGURE A-13 - TOP ROW, LEFT TO RIGHT: TUBE WITH 3 FINS,
TUBE WITH SINGLE FIN, TUBE (ONLY).
TUBE WITH STREAMER.
SECOND ROW: ROW OF TUBES WITH FINS, ROW
OF TUBES WITH STREAMER
FIGURE A-14 - SINGLE TUBE WITH STREAMER, NO VORTICES
80
-------
FIGURE A-15 - ROW OF TUBES WITH STREAMERS IN AN UPSTREAM
ANGLE IN FRONT OF 6 ROWS ON 2" /'. TO {~
FIGURE A-16 - AS ABOVE ONLY DOWNSTREAM ANGLE
81
-------
FIGURE A-17 - SINGLE ROW OF TUBES WITH FINS IN FREE
STREAM - VERY LITTLE TURBULENCE
FIGURE A-18 - ROW OF TUBES WITH FINS AT A DOWNSTREAM ANGLE
-
-------
FIGURE A-19 - ROW OF TUBES WITH FINS, UPSTREAM ANGLE
FIGURE A-20 - SAME AS ABOVE ONLY DEEPEN DRAFT
83
-------
FIGURE A-21 - TEST SM-7, 2.15 FPS
FIGURE A-22 - TEST SM-8, 2.1 FPS
-------
FIGURE A-23 - TEST SM-8, 2.1 FPS
FIGURE A-24 - TEST SM-8, 2.1 FPS
;;
-------
."V;
" '
FIGURE A-25 - SM-9, ARRAY OF 1.076" OD TUBES
FIGURE A-26 - SM-9, 1.95 FPS
86
-------
-.. ^
fel 5 i3!^'
^i r fV
M i-> I* Vl :^
I - ~j» 3»
FIGURE A-27 - 1.314" OD TUBES USED FOR TEST 10 AND 1
FIGURE A-28 - SM 10, 2.05 FPS
87
-------
FIGURE A-29 -
TEST SM-12, 1 05 FPS
BOOM 15 INCHES BEHIND BOOM
FIGURE A-30- TEST SM-12, ,.05 FPS
-------
FIGURE A-31 TEST SM-24, BOON 6" DEEP, 3.9 FPS
FIGURE A-32 - TEST SM-24, BOOM 3" DEEP, 3.9 FPS
-------
FIGURE A-33 - TEST SM-28, 8.25" DRAFT ON TUBES
FIGURE A-34 - TEST SM-31, HORIZONTAL BOARD IN PLACE,
9.4-INCH TUBE DRAFT
-
-------
APPENDIX B
DETAILS OF PERFORATED-PLATE BAFFLE EXPERIMENTS
(IPM 1 through IPM 33)
CONFIGURATION STUDIES
A detailed step-by-step summary of the individual inclined, perforated
plate baffle experiments run in the Shell Current Tank is found in Table B-l.
Figure B-l shows the configuration profiles and Tables B-2 and B-3 contain the
principal dimensions. Figures B-2 through B-32 are selected protographs taken
at various stages of experimentation.
FLOW ANALYSIS - FINAL CONFIGURATION
At the conclusion of the model tests a detailed flow analysis of the
inclined plate profile (see Figure B-33) was made. A Thermo Science Incorpo-
rated (TSI) hot wire anemometer probe was used to measure discrete points in
the velocity field caused by the boom profile. In this current tank test the
free-stream velocity was set at 4.8 fps (2.8 knots). The TSI probe was placed
at predetermined points to measure the velocity. Figure B-34 shows the mea-
sured points on the profile found by passing a vertical plane through the boom
such that the plate is parallel to the free-stream current vector. Figure B-35
contains measurements taken on a horizontal plane three inches below the
water's surface.
Point velocities shown in the two figures indicate that the effect of the
two perforated, inclined plates is that of creating a low velocity region just
in front of the aft barrier. Variations in readings where symmetry should
show identical results can be explained by flow variations and surges in the
test tank.
91
-------
TABLE B-l
SUMMARY OF PERFORATED-PLATE BAFFLE TESTS
Angle Front of Back of Draft of Ref. Vel. Vel. Boom
Test % of Plate Plate Plate Vel. x = 0 x/fps Location/Draft See
So. Open Plate x = in. x = in. y = in. fps fps in./fps in./in. Figure
Remarks
Decisions
IPM-1A 46%
IPM-1B 18.
18°
18°
1PM- 1C 18.8% 18°
IPM-2A 18.8% 18°
IPM-2B 18.
IPM-3 18.8% 18°
39
39
39
39
18° 39
39
IPM-4 18.8% 18° 39
IPM-5 18.8% 18° 39
IPM-6 18.8% 18° 39
IPM-7 18.8% 18" 39
69 10 2.20 2.21 87/1.65
69 10 2.20 2.21 S7/.47
69 10 2.20 2.21 S7/.24
69 10 2.25
69 10 2.25
69 10 2.25 2.26 63/.21
69 10 2.25 2.26 78/.4S
69 10 2.25 2.26
69 10 2.25
69 10 2.25
1-7
8,9
10,11
69/10
69/10
71/10 12
84/10 13
96/6
69/10
78/10 14,15
Only 25% reduction in Reduce open area.
current.
Observed some ventila- Place board @ water-
tion but would not line to reduce venti-
retain beads well. lation.
Stops ventilation but Try open-bottomed coke
would not retain beads crate without board.
well. Also insert rear
barrier.
Used coke box; surface Use board rather than
of H,0 turbulent but no coke case, because less
loss of beads.
surface turbulence
occurs.
Used board covering 1st Look at ventilation on
12 inches of holes; cor- upper part of inclined
ner vortices formed and plate without board but
beads were lost. with barrier. Try rear
barrier further back.
Did not lose plastic
beads.
Vortices formed in
front of barrier.
Try rear barrier fur-
ther back.
Move rear barrier fur-
ther back.
Occasional vortices Try the anti-ventila-
formed, occasional loss tion board again.
of beads at 6" draft.
Some of the board were Try coke box again.
lost.
Used coke box arrange- Use smaller angle for
ment; lots of turbu- inclined plate; no
lence. plate.
IPM-8 18.8% 11 26 69 9 2.25 2.28 42/.67 69/9 16,17
IMP-9 18.8% 11 26 69 9 3.0 2.80 48/.S9 69/9 18,19
NOTE: See Figure B-l and Table B-2 for test configuration and dimensions.
No ventilation; no
beads los t.
Try higher velocity.
Did not lose beads; 79% Try higher velocity.
reduction in velocity.
-------
TABLE B-l
SUMMARY OF PERFORATED-PLATE BAFFLE TESTS (Continued)
VD
U)
Plate
%
Test Open
No. #l/#2
IPM-10 18. 8/-
11 18.87-
Angle
of
Plate
#l/#2
12V-
12V-
Front
of
Plate
tl/#2
21/-
217-
Back
of
Plate
#l/#2
67/-
(,11-
Draft
of
Plate
#l/#2
12/-
12/-
Ref. Vel.
Vel. x=0
3.75
3.75
Vel.
x/fps
67/.90
Boom
Location/
Draft
117/6
105/6-11
No. of
Plate
Sets
1
1
Position
of
Plates
V
V
See
Figure
Calm in
of beads
Remai-ka
front of barrier
retained.
Barrier at 10" too deep,
; 80%
caus-
12 18.8/- 12V- 21/- 677- 12/- 3.75
13 18.8/- 12V- 217- 677- 12/- 3.75
14 46/18.8 16V13" 18/36 63/83 13/10 3.75
15 18.8/18.8 16°/18° 18/53 63/96 13/13 3.75
ISA 46/18.8 16V18" 18/53 63/96 13/13 3.75
16 18.8/18.8 157-12° 18/60 63/102 12/9 3.75
17 46/18.8 16°/19° 15/72 60/107 13/12 3175
93/6-11 1 V
81/6-11 1 V
105/12 2 V
105/.14 120/10
105/.28 120/10
115/6
117/10
18 18.8/18.8 16V19" 15/72 60/107 13/12 3.75 117/12
19 18.8/18.8 16°/19° 15/60 60/95 13/12 3.75 3.37 102/.45 117/12
2 V
2 V
2 V
2 V
2 V
2 V
ing too much back flow. Bar-
rier at 6" eliminates most of
the back flow. Try moving
closer.
Caused increased flow upstream
in front of boom. Try moving
barrier closer yet.
Boom too close; lost most of
beads. Try too inclined plates.
20 Too much ventilation; lost
beads; too much flow.
21 Reduce current flow; collected
beads. Try opening forward
plate.
Too much turbulence with 46%
open area in Plate 1. Try
another plate orientation
invert Plate 2.
22 Would not hold beads in front
of barrier. Try inverting both
plates.
23 Too much ventilation between
sets of plates; would not
collect beads. Try deeper
draft barrier.
Same problems. Try another way.
24 Same problems. Try another
configuration.
NOTE: See Figure B-l and Table B-3 for test configuration and dimensions.
-------
TABLE B-l
SUMMARY OF PERFORATED-PLATE BAFFLE TESTS (Continued)
Plate Angle Front Back
% of of of
Test Open Plate Plate Plate
No. fl/12 #l/#2 til 92 ti/«2
Draft
of
Plate Ref. Vel. Vel.
#i/#2 Vel. x = 0 x/fps
Boom No. of Position
Location/ Plate of See
Draft Sets Plates Figure
Remarks
20 46/18.8 19°/20° 18/28 60/75 14.5/17.5 3.75 102/10 2 V
21 18.8/18.8 18°/13° 21/48 63/95 13/11 3.75 3.93 108/10 2 V
22 46/18.8 18°/13° 21/48 63/95 13/11 3.75 107/10 2 V
22A 46/18.8 18°/13° 21/48 63/95 13/11 3.75 117/10 2 V
23 19.7/18.8 18°/13° 21/48 63/95 13/11 3.75 117/10 2 V
24 18.8/18.8 180/130 21/48 63/95 13/11 3.95 116/11 2 V
25 18.8/18.8 18°/13° 21/46 63/95 13/11 3.95 116/11 2 V
26 18.8/18.8 19°/16° 17/49 60/95 15/13 3.7 117/11 2 V
27 18.8/18.8 19°/16° 16/49 60/95 15/13 4.1 117/11 2 V
28 18.8/18.8 19°/16° 17/49 60/95 15/13 4.83 5.04 117/11 2 V
29 18.8/18.8 19V16" 17/49 60/95 15/13 5.06 5.09 117/11 2 V
25,26 Causes water to fall; beads are
lost and turbulence is severe:
would likely cause emulsions.
Change configuration.
27 Antiventilation board held in
place eliminates most venti-
lation.
Barrier 10" deep causes too much
current action in front of boom.
Better condition with barrier
further back; better with board.
28 Using board almost all beads
were caught.
Lost most of the beads. Horizon-
tal flow control board was not
used.
Lost most of the beads. Hori-
zontal flow control board was
not used.
29,30 With a set of three boards
rather than one, almost all of
the beads were retained (95%).
29,30 With this higher velocity, 90%
of all beads were retained.
All tests have 3 horizontal
boards in place; 80% of beads
were retained.
A slight increase in velocity
caused a 40% loss of beads.
NOTES: (a) Velocity readings taken with an Ott Kempten Current Meter next to Ducted meter at reference point six feet in front of incline
plate model.
(b) See Figure B-l and Table B-3 for test configuration and dimensions.
-------
Ui
TABLE B-l
SUMMARY OF PERFORATED-PLATE BAFFLE TESTS (Continued)
Test
No.
Plate
X
Open
#l/#2
Angle
of
Plate
#l/#2
Front
of
Plate
l/»2
Back
of
Plate
#1/12
Draft
of
Plate
tun
Ref.
Vel.
Vel.
x=0
\
Vel.a)
x/fps
Boom
Location/
Draft
No. of
Plate
Sets
Position
of
Plates
See
Figure
Remarks
IP»-30 48/18.8 20°/180 21/54 61/95 15/13 4.72 4.64 117/11 2 V
31 25/18.8 20°/18° 21/54 61/95 15/13 4.74 4.79 117/11 2 V
32 18.8/18.8 20°/18° 21/54 61/95 15/13 4.83 4.77 117/11 2 V
33 18.8/18.8 20°/18° 21/54 61/95 15/13 4.6 4.77 117/11 2 V
31 Last most of the beads. Horizontal
flow control board was not used.
32 75% of the beads were retained.
75% of the beads were retained.
Approximately 80% of all beads were
retained by model. Thus tests No.'s
IPM-28 and 53 are the best.
NOTES: (a) Velocity readings taken with an Ott Kempten Current Meter next to Ducted meter at reference point six feet in front of incline
plate model.
(b) See Figure B-l and Table B-3 for test configuration and dimensions.
-------
Trailing '
Boom Plate
TESTS IPM-1A THROUGH IPM-9
144"
PROFILE VIEW
TESTS IPM-10 THROUGH IPM-33
FIGURE B-l - SKETCH OF PERFORATED PLATE BAFFLE TEST CONFIGURATIONS
SEE TABLE B-l FOR SUMMARIZED RESULTS
96
-------
Test
No.
Vel.
X
TABLE B-2
PERFORATED PLATE BAFFLE PRINCIPAL
DIMENSIONS TESTS IPM 1 TO IPM 9
Plate
Angle
% Open Components
Area Used
IPM 1A 2.2 39 69
10
18
46
IB
2.25 39 69
10
18
18.8
1C 2.2 39 69
10
18
18.8
ca
2A 2.2
39 69 69 10 10
18
18.8
2B 2.25 39 69 69 10 10 18°
18.8
2.25 39 69 71 10 10
18
18.8
2.25 39 69 84 10 10
18
18.8
2.25 39 69 96 10
18
18.8
2.25 39 69 69 10 10 18°
18.8
2.25 39 69 79 10 10 18C
18.8
2.25 26 69 69
11
18.8
3.0 26 69 69
11
18.8
a) Board was used
b) Coke box was used
c) Boom and trailing plate were not used
97
-------
00
TABLE B-3
PERFORATED PLATE BAFFLE
PRINCIPAL DIMENSIONS
Test
No.
10
11
12
13
14
15
15A
16
17
18
19
20
21
Plate
Incli-
nations
V
V
V
V
V
V
V
V
V
V
V
V
V
TESTS IPM-10 TO IPM-33
Coordinates
(in.)1
21,0
21,0
21,0
21,0
18,0
18,0
18,0
18,0
15,13
15,13
15,13
18,14.5
21,0
X2, Y2
(in.)
57,10
67,10
67,10
67,10
63,13
63,13
63,13
63,12
60,0
60,0
60,0
60,0
63,13
X3, Y3
(in.)
-
-
-
36,0
53,0
53,0
60,9
72,0
72,0
60,0
28,17.5
48,0
(in.)
-
-
-
-
83,10
96,13
96,13
102,0
107,12
107,12
95,12
75,0
96,11
(Deg)
12
12
12
12
16
16
16
15
16
16
16
19
18
2*
(Deg)
-
-
-
13
18
18
12
19
19
19
20
13
X5
(in.)
117
105
93
81 i
105
120
120
115
117
117
117
102
108
(in.)
6-11
6-11
6-11
6-11
12
10
10
6
10
12
12
10
10
% Open Area
Plate 1
18.8
18.8
18.8
18.8
46.0
18.8
46.0
18.8
46.0
18.8
18,8
46.0
18.8
Plate 2
-
-
-
-
18.8
18.8
18.8
18.8
18.8
18.8
18,8
18.8
18.8
*<(> and 9 are measured from the water line to the plate for both cases (planing or diving).
-------
TABLE B-3 (Continued)
vo
VO
Test
No.
22
22*
23
24
25
26
27
28
29
30
31
32
33
Plate
Incli-
nations
V
V
v
v
V
V
V
V
V
V
V
V
V
Coordinates
(in.)1
21,0
21.0
21,0
21,0
21,0
17,0
17,0
17,0
17,0
21,0
21,0
21,0
21,0
X2> Y2
(in.)
63,13
63,13
63,13
63,13
63,13
60,15
60,15
60,15
60,15
61,15
61,15
61,15
61,15
XV
"}» M
(in.)"
48,0
48,0
48,0
48,0
48,0
49,0
49,0
49,0
49,0
54,0
54,0
54,0
54,0
(in. )
95,11
95,11
95,11
95,11
95.11
95,13
95,13
95,13
95,13
95,13
95,13
95,13
95,13
1*
0>eg)
18
18
18
18
18
19
19
19
19
20
20
20
20
4>2*
(Deg)
13
13
13
13
13
16
16
16
16
18
18
18
18
X5
(in.)
107
117
117
116
116
117
117
117
117
116
117
117
117
(in.)
10
10
10
11
11
11
11
11
11
11
11
11
11
% Open
Plate 1
46.0
46.0
18.8
18.8
18.8
18.8
18.8
18.8
48.0
25.0
18.8
18.8
Area
Plate 2
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
18.8
-------
FIGURE B-2 - TEST SETUP, TOP VIEW
FIGURE B-3 - INCLINED PLATE SETUP, 18.8% OPEN
100
-------
FIGURE B-4 - SIDE VIEW THROUGH TANK WINDOW
FIGURE B-5 - PERFORATED INCLINED PLATES WITH REAR BOOM
101
-------
FIGURE B-6 - IPM-1A: SIDE VIEW, 2.2 FPS, 46% OPEN
1 *i»>»
J <*tvK*
FIGURE B-7 - IPM-1A: TOP VIEW, 46% OPEN, 2.2 FPS
102
-------
FIGURE B-8 - IPM-1B: TOP VIEW, 18.8% CLOSED, 2.2 FPS
FIGURE B-9 - IPM-1B: SIDE VIEW, 18.8% OPEN, 2.2 FPS, VENTILATION
103
-------
FIGURE B-10 - IPM-1C: ANTIVENTILATION BOARD ON TOP OF PLATES
FIGURE B-ll - IPM-1C: 18.8% OPEN, 2.2 FPS
104
-------
-V
,
FIGURE B-12 - IPM-3: 18.8% OPEN, 2.25 FPS, BOOM IN PLACE
FIGURE B-13 - IPM-4, 18.8% OPEN, 2.25 FPS, BOOM AT X = 84
105
-------
y-
\
m
*
FIGURE B-14 - IPM-7: COKE BOX ARRANGEMENT, NOTICE TURBULENCE;
18.8% OPEN, 2.25 FPS
,
'r-.\-
:..'':
'' ^ '' '
^^*4**1 :--:: *j
**S%2*Mi
. f.i . tn
FIGURE B-15 - IPM-7: PHOTO OF COKE BOX ARRANGEMENT
106
-------
FIGURE B-16 - IPM-8: SIDE VIEW AT 2.25 FPS WITH 18.8% OPEN AREA
i. '
-'-
* * '
FIGURE B-17 - IPM-8: 18.8% OPEN AREA, 2.25 FPS, BOOM AT END OF PLATE;
NOTICE QUIET SURFACE IN FRONT OF THE BOOM
107
-------
FIGURE B-18 - IPM-9: 3.0 FPS, 18.8% CLOSE, SURFACE OF WATER IS STILL
FIGURE B-19 - IPM-9: SIDE VIEW, 18.8% OPEN AREA AT 3.0 FPS
108
-------
>*^ -
///.
V S
FIGURE B-20 - SET-UP FOR IPM-14, NO CURRENT
FIGURE B-21 - TEST IPM-15, 3.75 FPS
109
-------
FIGURE B-22 - TEST IPM-16, 3.75 FPS
.»
FIGURE B-23 - TEST IPM-17, 3.75 FPS, BOOM 10" DEEP
110
-------
FIGURE B-24 - TEST IMP-19, 3.75 FPS, BOTH PLATES 18.8% OPEN
FIGURE B-25 - TEST IPM-20, 3.75 FPS
111
-------
FIGURE B-26 - TEST IPM-20, 3.75 FPS
FIGURE B-27 - TEST IPM-21, HAND HOLDING BOARD ON
UPSTREAM SET OF PLATES, 3.75 FPS
112
-------
FIGURE B-28 - TEST IPM-23 FPS, HAND-HOLDING BOARD
113
-------
FIGURE B-29 - TESTS 26 AND 27, BOARDS IN PLACE
FIGURE B-30 - TESTS 26 and 27, SIDE VIEW
114
-------
i
FIGURE B-31 - TEST IPM-30. PLATE 1 IS 48% OPEN
AND PLATE 2 IS 18.8% OPEN; THE
VELOCITY IS 4.7 FPS
FIGURE B-32 - TEST IPM-31, PLATE 1 IS 25% OPEN
AND PLATE 2 IS 18.8% OPEN; THE
FREE STREAM VELOCITY IS 4.7 FPS
115
-------
IMPERVIOUS BOARDS TO PREVENT VENTILATION
FLOW
'18.8% OPEN AREA (TYP)
PROFILE
SCALE l"= 16"
OPEN (TYP)
DETAIL OF HOLE PATTERNS
FIGURE B-33 - OPTIMUM INCLINED PLATE BAFFLE BOOM ARRANGEMENT
BASED ON FULL SCALE TESTS IN CURRENT TANK
-------
TOP OF SIDEWALL
AFT INCLINED PLATE
HN.T.S.)
AFT BARRIER
-6'
I
-4'
11
-2'
-X
L02 763 475 J0t7 .17 .085 .085
1.61
1.61 186 L52 L59 L86 2.29
5L
h-
-j
4.61
6"_
546
12" !_
18? _
24'_
5.03 5.12 4.74 5.25 4.83
* .
f
4.95 5.43 5.43 5.42
FLOW
5.42
SCALES:
x: i"=r-o"
4.16
FWD INCLINED PLATE
(4 N.T.S.)
FIGURE B-34 -
POINT VELOCITIES FOR A ?. PLANE THROUGH INCLINED PLATE PROFILE.
FREE-STREAM VELOCITY IS 4.8 FPS (2.8 KNOTS). VELOCITIES SHOWN
ARE IN FPS.
-------
12'-0" SIDEWALL (TYP)
CO
-X
+X
f
1' 1
4.61 5.03 5.12 4.74 5.25
FLOW
Mi
SCALES: x. r-a'-b"
7
TOP OF FWD PLATE
AT W.L.
5.09
4.83
4.66
0
r
i
4.15
r
3.98
_
4.24
f
2' 4' /
1 1 /
/
5.17 4.75 5.00 3.56 1.70
* *! * * *
4.75 3B2 425 3.73 178
i
i
4.92 370 4.66 3.22 2.03
1
6'
1
1.70
1.02
.49
81 \ 10'
1 \ 1
\
| *
44 .61 .85 .34 .424 .25
i
.76 48 .017 .017 .085 .085
f -
i
I
.170 .09 .0 .017 0 .085
f
J
-9
0
-4.Q
7
BOT OF AFT PLATE
BELOW W.L.
FIGURE B-35 - POINT VELOCITIES FOR A HORIZONTAL PLANE 3" BELOW THE WATER'S SURFACE.
THE FREE-STREAM VELOCITY IS 4.8 FPS (2,8 KNOTS) IN FRONT OF THE
INCLINED PLATE BOOM PROFILE.
-------
APPENDIX C
SUMMARY OF PERFORATED PLATE TOW TESTS
INTRODUCTION
These tests were run to determine the specific boom configuration that
gives the greatest oil retention rate at a 2-1/2 knot tow speed without waves.
The boom section shown in Figure 27 in the body to this report is to be modi-
fied in an effort to enhance its oil retention capacity. Previous tests were
run with PVC beads, so these are the first ones using oil. Results are given
in Table 1 of the main report.
The Shell wave/tow tank shown in Figure 33 was used for the tow and tests.
The initial boom position and the test section are indicated. Figure C-l
shows the test rigging used to apply and contain oil. The test oil for this
phase of tests is a Navy Distillate oil, similar to No. 2 Fuel Oil in physical
properties.
TEST PROCEDURE
The procedure for each tow run is generally as follows:
1. Check wave/tow tank for accumulated oil from previous runs. If oil
is present, remove it or isolate it with a boom so that oil lost from
the test to be run can be separated.
2. Place the boom section and associated apparatus in the aft slip of
the tow tank. Attach cables and hoses.
3. (a) If the test to be run is a "constant volume" one, slowly pour
the oil into the rear area of the boom using a tear-away barrier
forward to restrain the oil before the tow run.
(b) If the test is a "constant flow rate" one, start the oil flow
from the storage tank into a return sump by turning on the pump
switch. After flow is initiated and after the boom reaches the
beginning of the 100' test section, activate a 3-way valve to
direct the flow into the hose that feeds oil in front of the
boom during the tow run5?
4. Start the electric powered winch to initiate the tow run. Control
the speed to affect all of the acceleration before the start of the
* The flow has been previously calibrated by timing the oil accumulation in a
5-gallon drum.
119
-------
Pulling on back line raises
curtain during test run.
Releasing rope
closes curtain. \ XX
Flexible Plastic Joint
to Seal Against
Oil Leaks
oom
Section
(Test Item)
Oil Containment Area
and Drop Curtain
(Test Fixture)
Hinge
Oil Supply
Hose
Tow Line
FIGURE C-l - TEST RIGGING FOR APPLYING AND CONTAINING THE OIL
120
-------
test section is reached. Hold the winch speed constant while the
boom moves through the 100' test section.
5. If the run is a constant volume test, raise the curtain when the
speed is high enough to force the oil to the rear barrier of the boom.
If the run is a constant flow rate one, raise the curtain any time
before the 3-way valve is turned to apply the oil.
6. After the boom passes the end point of the test section:
Constant Flow Rate Test. Divert the oil flow back to the sump
using the 3-way valve. After decreasing the winch speed, release
the aft rope to lower the oil confining curtain.
Constant Volume Test. Same as for Constant Flow Rate Test
except omit the 3-way valve change.
7. Check to see that oil is not lost under the forward curtain during
the deceleration phase. If oil is lost in front, use water hoses to
separate this loss from the loss under the boom during the test run.
8. Remove the oil lost under the skimmer from the tank and measure it.
Remove the oil remaining in the skimmer and measure it. Notes;
(a) take care not to emulsify oil during pickup; (b) allow adequate
time for gravity settling of oil in container prior to measuring the
volumes of oil.
121
-------
APPENDIX D
THREE-DIMENSIONAL TOW TESTS - HOUSTON
At the conclusion of the two-dimensional test program three-dimensional
(diversion) tests were also conducted at Houston. Five four-foot-wide boom
segments were joined side-by-side to form a 20-foot-long high-current boom.
The boom was attached to the towing bridge with cables and a trailing boom was
attached to the downstream end of the high-current boom to separate the oil
successfully diverted during the run from that lost under (or over) the high
current boom.
Oil was applied to the water in front of the advancing boom using a wide
pipe manifold attached to the bridge. Equally spaced holes in the pipe allow
oil to flow onto a flexible plastic curtain. The overlaping flow plumes run
down the curtain onto the water creating an approximately uniform thickness
oil lens about six feet wide. Normally the manifold was located to allow the
oil to approach the boom at mid-length. Oil was applied to the water at a
constant flow rate for a tow distance of 75 feet.
Figure D-l shows a sketch of the test set-up in the wave tank.
The tow test conditions and results are contained in Table D-l. Notice
that all of the oil diversion percentages are above 90%. By comparing the
results of Table D-l with those for the OHMSETT tests (Table 5 in the main
body of this report), one finds that the results (excluding the denser Navy
Special oil tests) are similar except for tow runs above 2.5 knots. At the
higher speeds we feel that the Houston tank is too short (for towing wide
devices) and that the oil losses under the high-current boom would be created
in a longer tank.
We conclude that the OHMSETT diversion test results are more reliable
than the results from this short tank. Consequently these results were not
relied upon in quantitatively assessing the performance of the high-current
boom in diversion.
122
-------
N3
20' High-Current Boom
Wave Absorber
Tow Winch
Oil Storage
Trailing Boom
FIGURE D-l - BOOM TEST SET-UP IN HOUSTON WAVE/TOW TANK
-------
TABLE D-l
DIVERSION TESTS OF THE EPA HIGH CURRENT BOOM
HOUSTON TANK
Run- Angle
1-15°
1-30°
1-45°
1-60°
2-15°
2-30°
2-45°
2-60°
3-60°
4-15°
4-45°
5-45og)
6-45oS)
7_45°g)
8-45°g)
9-45°
10-45°
11-45°
12-45°
13-45°
NOTES: a)
b)
c)
d)
e)
f)
8)
h)
i)
j)
Steepness Equiv. Slick
Wave Height Ratio Thickness
Knots (ft) (H/L) (mm)
2.4 2.3
2.4 2.5
2.5 2.2
2.5 -- 2.2
3.0 1.9
2.9 1.8
3.0 1.9
3.0 1.8
3.6 1.6
2.4 0.5 0.05 2.2
2.4 0.5 0.05 2.2
2.5
2.6 0.5 0.05 2.0
2.5 1.0 0.05 2.0
2.4 2.4
2.5 1.0 0.05 1.5
2.5 1.0 0.05 1.5
2.5 0.5 0.05 1.3
2.5 1.3
2.5 1.6
Five four-ft wide boom sections were used.
The transverse direction is 0°, the tow direction is 90
Oil flow from the nozzle was begun at the start of the
tow line.
Navy Distillate was used in the tests (6 cp at 77°F).
Percent
Oil Loss
2.6
1.3
0.8
3.0
2.0
1.1
2.6
1.3
0.9
1.5
2.8
9.6
9.1
3.5
4.3h
9.61
6.01
4.41
6.4^
O
*
75-ft
Percent oil loss based on comparison of the total volume lost
with the total volume applied.
Center of nozzle in line with center of boom, except as
Center of nozzle moved from center of boom 4-ft toward
edge of boom.
Oil applied at starting point.
Oil applied 10-ft before starting point.
Oil applied 25-ft before starting point.
noted.
leading
124
-------
APPENDIX JS
OHMSETT TEST FACILITY
The U.S. Environmental Protection Agency is operating on Oil and Hazar-
dous Materials Simulated Environmental Test Tank (OHMSETT) located in Leonardo,
New Jersey. This facility shown in Figure E-l provides an environmentally safe
place to conduct testing and development of devices and techniques for the
control of oil and hazardous materials spilled in inland and coastal waters.
The primary feature of the facility is a pile-supported, concrete tank
with a water surface 667 feet long by 65 feet wide and with a water depth of
8 feet. The tank can be filled with fresh or salt water. The tank is spanned
by a towing bridge which can tow loads up to 34,000 Ibs. at speeds to six knots
for a duration of 45 seconds. Slower speeds yield longer test runs. The
towing bridge is equipped to lay oil on the surface of the water several feet
ahead of the device being tested, such that reproducible thicknesses and widths
of oil slicks can be achieved with minimum interference by wind.
The principal systems of the tank are a wave generator and beach, a bub-
bler system, and a filter system. The wave generator and absorber beach have
capabilities of producing non-reflecting waves to two feet high and 80 feet
long, as well as a series of reflecting, complex waves which simulate the
complex water surface of a harbor or estuary. The water is clarified by recir-
culation through a diatomaceous earth filter system to permit underwater
photography and video imagery, and to remove the few ppm of hydrocarbons that
remain after a test. A bubbler system which prevents oil from reaching the
tank walls, the beach, or the wave generator. This system is designed to
speed cleanup between test runs, since a clean tank surface is essential to
reproducible oil spill conditions. The towing bridge has a built-in skimming
board which, in conjunction with the bubbler system, can move oil on to the
farthest end of the tank from the generator for cleanup and recycling.
When the tank must be emptied for maintenance purposes, the entire water
volume (2.6 million gallons) is filtered and treated until it meets all appli-
cable state and federal water quality standards before being discharged.
Tests at the facility are supported from a 7,000 square foot building
adjacent to the tank. This building houses offices, a quality control labora-
tory (which is very important since test oils and tank water are both recycled)
a small machine shop, and an equipment preparation area.
OHMSETT is a government owned, contractor operated facility. The operat-
ing contractor, Mason and Hanger-Silas Mason, Co. Inc., provides a staff of
eleven multidisciplinary personnel. The U.S. Environmental Protection Agency
provides project guidance and expertise in the area of spill control technology.
125
-------
I
1
FIGURE E-l - THE EPA WAVE/TOW TANK CALLED OHMSETT
-------
APPENDIX F
on '
Type
Sun 75
Sun 75
Sun 75
Sun 75
Sun 75
Sun 75
Sun 75
Sun 75
12 Fuel
#2 Fuel
M? Fuel
Applied or
Recovered
Test #
Applied
Tests 1*?
Applied
Test 3
Recovered
Test 4
Recovered
Test 6
Recovered
Test 5
Applied
Tests 7&8
Recovered
Test 7
Recovered
Test 8
Applied
Test 9&10
Recovered
Test 9
Rprm/pred
APPLIED AND RECOVERED OIL PROPERTIES
OHMSETT TESTS
Oil Interfacial
Oil Sp. Surface Tension
Temp Gr. Tension Oil /Sea
V(cs) (°F) (g/cc) (dynes/cm) Water
267 120 0.875 30.1 9.1
863.3 88 0.890 30.8 13.8
68
74
75
578.5 110 0.886 31.6 9.6
73
73 -
7.1 80 0.847 28.8 13.6
- - - -
. - - -
Percent
Water
0.8
9.0
25.0
21.0
25.0
8.0
30.0
20.0
-
3.0
8.5
Test 10
127
-------
SELECTED PHOTOGRAPHS, OHMSETT TESTS
FIGURE F-l - TEST 2. BOOM AT 45° USING SUN 75 OIL,
TOW VELOCITY 3.0 KNOTS, NO WAVES
,
FIGURE F-2 - TEST 5. BOOM AT 45° USING SUN 75 OIL,
TOW VELOCITY 3.25 KNOTS, WAVES 6" HIGH
AND 3 SECOND PERIOD
128
-------
SELECTED PHOTOGRAPHS, OHMSETT TESTS
FIGURE F-3 - TEST 6. BOOM AT 45° USING SUN 75 OIL,
TOW VELOCITY 3.0 KNOTS, WAVES 8" HIGH
AND 2 SECOND PERIOD
FIGURE F-4 - TEST 9. BOOM AT 45° USING NO. 2 FUEL OIL,
TOW VELOCITY 3.0 KNOTS AND NO WAVES
129
-------
SELECTED PHOTOGRAPHS, OHMSETT TESTS
FIGURE F-5 - TEST 10. BOOM AT 45° USING NO. 2 FUEL OIL,
TOW VELOCITY 3.0 KNOTS, WAVES 8" HIGH
AND 2 SECOND PERIOD
130
-------
APPENDIX G
ENGLISH - METRIC CONVERSION TABLE
Multiply
feet
feet/second
feet/second2
gallons
galions/minute
inches
knots
pounds
pounds/cubic foot
bjr
0.305
0.305
30.480
3.785
0.063
2.540
0.515
453.600
0.016
To Obtain
meters
meters/second
centimeters/second2
liters
liters/second
centimeters
meters/second
grams
grams/cubic centimeter
131
-------
TECHNICAL REPORT DATA
/I'lcasc read Instructions on the reverse before com/1'1
1 RtPGfl I NO.
EPA-600/2-76-263
2.
3. RECIPIENT'S ACCESSION'NO.
4. TITLfc AND SUBTITLE
A RIGID, PERFORATED PLATE OIL BOOM FOR HIGH CURRENTS
5. REPORT DATE
December 1976 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Ray R. Ayers
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Shell Development Company
Westhollow Research Center
P. 0. Box 1380
Houston, Texas 77001
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
68-03-0331
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory-Gin., OH
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final: July 1978-May 1976
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A boom capable of diverting oil spills toward shore in a 3-knot (1.5 m/s) river
or tidal current has been developed. Loss of No. 2 and No. 4 Fuel Oil at this
velocity is typically less than 15 percent when the angle of the boom is 45 degrees
to the shoreline. In contrast, conventional booms lose this amount at only 1 knot
(0.5 m/s).
Good performance at high currents is achieved by placing a baffle upstream of
a conventional flat plate boom. The baffle, an inclined, perforated plate, is used
to create a flow-sheltered region where the oil layer thickens. A continuation of
the inclined plate baffle forms the "floor" of the sheltered region to control the
flow rate of exiting water. Horizontal plates immediately behind the baffle reduce
water down-flow.
The boom is made up of 8-foot (2.4 m) long, rigid sections similar in plan view
to a floating dock module. The length of the boom depends upon the number of modules
pinned together side by side. Floating suction or sorbent rope collection devices may
be used to remove accumulated oil from the flow sheltered region and increase "capa-
city" .
Drawings are provided to permit construction by others.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Water Pollution
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Oil Spills,
Booms,
Barriers
13B
3. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
142
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
132
U.S. GOVERNMENT PRINTING OFFICE: 1977-757-056/5'i69 Region No. 5-11
------- |