-------
by changing the effective source location (virtual source). A convergence of
the ground-level concentration in the wake of the building to the value
measured ir the absence of the building was found to occur in the far wake
region.
This study was conducted to examine the general influence of a squat
building upon plume entrainment and to provide data that would be useful to
an evaluation of presently available methods used to estimate concentrations
from stacks near buildings. Sources placed away from the building should be
influenced less than was observed in this study. The results are applicable
primarily to neutral or slightly unstable atmospheric conditions. Because
of the rather complex effects that buildings can have on plume entrainment
and the likely variation with each unique situation, additional study is
needed to provide further clarification. Further study and guidance is
important because the entrainment of plumes emitted from short stacks into
the wakes of buildings can result in maximum ground-level concentrations
that are significantly greater than those found for similar sources in the
absence of buildings.
-------
SECTION 3
DESIfN OF EXPERIMENT
EXPERIMENTAL EQUIPMENT
The study was conducted in the Meteorological Wind Tunnel of the U.S.
Environmental Protection Agency's Fluid Modeling Facility. The wind tunnel
has a test section 3.7 x 2.1 x 18.3 m. The flow speed within the wind tunnel
can be controlled between 0.3 and 10 m/s. Further details of the wind tunnel
may be obtained from Snyder (1979a).
For mean velocity and turbulence intensity measurements, a Thermo-
Systems, Inc., Model 1054A anemometer was used in conjunction with their
Model 1210-20 cylindrical hot-fi"m probes. Signals were fed to a Thermo-
Systems Model 1057 signal conditioner and then to a Digital Equipment Corpora-
tion PDP-11/40 minicomputer for A/D conversion and processing. Reported
measurements are for one-minute averaging times, which were found to yield
reasonably stable values.
For making concentration measurements, methane was mixed with the stack
gases as a tracer. The amount of methane in the effluent was 1% by volume for
all except those concentration measurements taken beyond 15 building heights
downwind, where 4% was needed to increase precision. At selected positions,
a sanple gas stream was drawn through a 0.16 cm i.d. metal probe that was con-
nected by Teflon tubing to a Beckman Model 400 Hydrocarbon Analyzer, which is
a flame ionization detector. The sample flow rate through the probe was 200
cm3/irin, of which a 15 cm3/min sample was diverted through the analyzer. The
0.5 s response time of the analyzer was too long to permit examination any
dispersion microstructure. Instead, concentrations were averaged over a
sufficiently long time period (one min.) to represent steady-state values.
The output from the hydrocarbon analyzer was also digitized and processed on
the minicomputer.
The hydrocarbon analyzer has a linear response for concentrations less
than about 4%. The analyzer scale was first zeroed by sampling bottled air,
which contained less than 0.5 ppm hydrocarbons. The upper limit of the
6
-------
scale was set by sampling the stack effluent stream. Pollutant concentrations
down to dilution levels of 1:10,000 can be accurately measured. Background
concentrations were carefully monitored. The change in background concentration
during the period of measurement was generally small (of the order of 1/10,000th
of the stack concentration). A linear time dependence was assumed and found to
quite adequately account for the change in background; in processing the data,
the background was first subtracted out. In the regions of lowest concentration
(outer fringe of the plume), where measured concentrations were of the order of
the change in the background, measurements cannot be considered to be as ac-
curate.
A smoke generator was used for the visualization of the stack effluent
path. The oil-fog generator was connected in-line with the stack air line.
Photographs of the side views of the smoke plumes were taken using a 35 mm
camera with a 135 mm lens. The camera was mounted 10 m perpendicularly to the
plume center!ine-. A four-second continuous exposure on ASA 400 film was used
to provide the photographs shown in this report.
SIMILARITY CRITERIA
In order to insure that the flow in the model simulates that under full-
scale atmospheric conditions, it is necessary to meet certain similarity
criteria. Various nondimensional parameters must be matched in model and
prototype. Discussions of similarity criteria can be found, for example,
in Snyder (1972, 1979b), Cermak (1971), and Halitsky (1969). Since this study
is concerned only with neutrally stable atmospheric flows and relatively
small scales, the Richardson and Rossby numbers may be ignored. In modeling
buoyant stack effluents, however, the stack Froude number is important. The
parameters of significance are a; follows;
B . « . U
WVV
Ws WsDs UrHb
[gDs(pa-ps)/pa]V2 v '
-------
The first two of these parameters are easily matched by constructing a
scale model. The model building, 25 cm in height, was constructed with a
length (perpendicular to the wind) to height ratio, L/H,, of 2:1 and a width
to height ratio, B/H. , of 1:1.
In performing fluid modeling studies, it is important to simulate the
atmospheric boundary layer. A method similar to that of Counihan (1969),
which uses a barrier at the test section entrance slightly upstream from
vortex generators, was used to produce a thick, simulated atmospheric
boundary layer. These experiments used a 0.38 m high castellated barrier
placed at the test section entrance followed immediately by four 1.83 m high
semi-elliptic wedge-shaped vortex generators. These were followed by 0.019 x
0.05'! m roughness slats placed downstream at C.457 m intervals to maintain the
boundary layer in equilibrium. A previous experimental study showed the
boundary layer to maintain equilibrium and uniformity beyond 8 m downwind
from the vortex generators. The model building was placed 9 m downwind from
the vortex generators for all experiments except part of those in Phase III,
where the building was moved 2.5 m upwind. A sketch of the experimental ar-
rangement is shown in Figure 2.
Mean velocity and turbulence intensity measurements taken at the building
location and at 10 building heights downwind are shown in Figures 3 and 4.
All experiments were conducted under these conditions. Previous experimental
study showed a free-stream velocity greater than 1.5 m/s was necessary for the
development of an equilibrium boundary layer.
The depth of the boundary layer 6 was 1.8 m. This fixed the boundary
layer thickness to building height ratio 6/H. equal to 7:1. The velocity
orofile U/Ur was found to fit a one-sixth power law, which is generally re-
presentative of neutral atmospheric flow over moderately smooth terrain
(Pavenpor , 1963). The reference velocity U was measured at 1.5 H. above
the surface. The local turbulence intensity was 25 percent near the surface,
which is also representative of neutral conditions over moderately smooth
terrain (Harris, 1968).
A variety of combinations of ratios of stack height to building height
HS/HP stack diameter to building height D /Hj,, stack effluent speed to wind
spee( at the top of the stack WS/J$> and the stack effluent density to
ambient air density pc/pa were modeled.
S a
-------
TEST SECTION
-18.3m-
ROUGHNESS ELEMENTS
VORTEX GENERATORS
CASTELLATED BARRIER
Figure 2. Diagrammatic sketch of the wind tunnel and experimental arrangement.
-------
T
N
4.0
3.5!
3.0
O K '
2.0
1.5
1.0'
0.5
i-
MEAN VELOCITY
U
Ur
WITH BUILDING
O x/Hb=0
WITHOUT BUILDING
Q x/Hb-u
A x/Hb=10
-cr-
0.25 0.5 0.75 1.0 1.25 1.5
U/Ur
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
"i •" 'i" " I111 i' • • • i1 • :
TURBULENCE INTENSITY;
I
1 ^P WITH BUILDING
WITHOUT BUILDING
Dx/Hb=0
Ax/Hb=10i
1111111111
5 10 15 20 25 30 35 40
u2/U, percent
Figure 3. Velocity and local turbulence intensity measurements, Ur = 2.34 m/s (Ur = reference velocity at z/Hb = 1.5).
-------
4.0
3.5
3.0
2.5!
X 2.0
~N
1.5
1.0
0.5
0
Ill I I I I I 1 I I I I 1 I I I I 1 I
MEAN VELOCITY1
'- WITHOUT BUILDINGI D
: a x/Hb=fo
4.0.
3.5
3.0 i
£ 2.0
1.5
1.0
0.5
0
Fill I l»l[ll 111 I 11 I 11 I 11 I 11 I 11' I 11 £ 11 11
I TURBULENCE INTENSITY^
i
9° WITHOUT BUILDINGlj
I O x/Hb=0 1
9° Dx/Hb=10|
do
l
5 10 15 20 25 30 35 40
u2 / U, percent
0.25 0.5 0.75! 1.0 1.25 1.5
U/Ur
Figure 4. Velocity and local turbulence intensity measurements, Ur = 4.34 m/s (reference velocity at z/Hb = 1.5)
-------
Plume rise near the stack is dominated by the momentum flux of the
2 2
effluent, so that correct modeling of the ratio p VI / p U is important.
s s as
Farther downwind where buoyancy becomes the dominating factor, the stack Froude
number, Fr = W /[gD (p, - p )/p ] , is a significant parameter to consider
s s a s a
(Brigcs, 1975, and Csanady, 1973). The smallest stack effluent speed and the
largest stack diameter possible are needed to most favorably model typical
buoyancy-dorr inated plumes in a wild tunnel. Because a free-stream wind tunnel
speed greater than 1.5 m/s was found to be necessary for the development of a
uniform equilibrium boundary layer, reductions in the stack effluent velocity
are rather limited if typical values of the ratio of effluent speed to wind
speed are to be modeled. A slight exaggeration of the density ratio Ap/p=
a
was possible. A value of 0.5 was maintained in all buoyant cases. To
avoid entrainment effects, Hoult (1973) suggested maintaining the density
ratio at less than 0.4. We feel that the value of 0.5 used in this study
introduced no unusual effects.
Matching the stack Reynolds number, Re = W D /v where v is the kinematic
o o o
viscosity, is rot important if the stack effluent streams are fully turbulent.
A value of 2000 is well established for the maintenance of turbulent flow in
a pine. Hoult and Weil (1972) reported that a value of 300 is sufficient for
modeling stack gas effluent situations. For this study the stack Reynolds
number was greater than 1000 for all cases. To help insure a turbulent
effluent stream, two serrated washers All,000. A model study by Smith (1951)
showed the extent of the cavity region leeward of a squat building to be
independent of Reynold's number provided that Reb>18,000. These model
results were found to compare well with those of a full-sized building. The
building examined by Smith was rectangular in shape with the building length
12
-------
(perpendicular to the wind direction) about twice the building height. This
is similar in design to the one used in the present study where the building
Reynolds number exceeded a value of 36,000 in all cases.
The choice of building height is a compromise. Large scale models
permit a more refined network of sampling points and provide higher Reynolds
numbers. In modeling situations where buoyant stack emissions are considered,
''arger scale models additionally permit smaller, more favorable, stack Froude
numbers. However, the scale model size is limited by the test section size
of the wind tunnel, hence, the simulated boundary layer depth. For this
experimental study, a 1:200 scale model of a 50 m high prototype building
would be an appropriate example. On this scale, the wind tunnel boundary
layer (1.8 m) represents a 360 m deep atmospheric boundary layer.
Concentrations measured in the model are related to those that would
be measured in the field over a time period where the background flow
remained constant and similar to the model case (of the order of 10 min). For
the situations modeled in this study, the stack effluent may be assumed to
behave as if it were emitted from a point source. Thus, the field concen-
tration xp is linearly related to the model concentration XM> to the inverse
of the model emission rate QM, to the field emission rate 0-, and to the
2 2
dilution ratio (UrHb)M / (urHb)p- Tne dilution ratio represents a comparison
of a unit volume of flow in the model to the similar scaled volume in the
full-scale flow. These basic relations result in the expression
Model
All concentration data are presented in the above nondimensional form.
The reference velocity Ur was taken at an elevation of 1.5 building heights.
The velocity at this position was found to be 85 percent of the free-stream
value. The velocity at the top of the other stacks examined were within
10 percent of this value (except, of course, the ground level source).
13
-------
EXPERIMENTAL PLAN
The main objective of this study was to examine the wake effects, from a
typical building, upon effluents under a variety of stack exit conditions.
This study examined 30 basic cases, whose stack conditions are shown in
Table 1. For each case, an examination was made of the plume behavior with
the building in position and then simi'arly repeated with the building re-
moved. This allowed for a simple demonstration of the building wake effects.
The reference velocity was maintained at 2.32 m/s for all cases except
those having a velocity ratio W$/US equal to 0.4. For these cases the wind
speed was increesed to 4.34 m/s. Four different stack diameters were used.
On a 1:200 scale, prototype stacks in the range of 1-10 m were thus modeled.
The smaller diameters were used for the shorter stacks, and the largest diam-
eter was used solely for the tallest stack. The lower Froude number situations
(Case Nos. 3, 14, 16, 22, 24, 28, 30), for example, are representative on a
1:200 scale of a stack effluent with a gas temperature of 600 K and exit ve-
locity of 20 m/s. The experimental study was conducted in three phases, as
outlined be'ow.
Phase I: Flow Visualization
For all 30 cases, side view photographs were taken of the smoke plumes
within the near building region. Case Nos. 1-20 were found to be represen-
tative of the most significant building effects.
As mentioned in the introduction, the conceptual cavity of Halitsky (1968)
has been contested by Britter et il. (1976). Reverse flow still occurs
downwind of the building, but Britter et al. contend that the streamline that
leaves the building at the separation line is not necessarily the same as
the streamline that reattaches at the rear stagnation line (see Figure 1).
Since the recirculating region of flow is not closed, it is difficult to de-
fine a "cavity" in terms of streamlines. Since the concept of a building
cavity is a useful one for discussion purposes, it will be redefined here.
The bubble (enclosing the cavity) is really a three-dimensional surface, a
point not fully addressed by Halitsky or Britter et al. The bubble, as de-
fined here, begins on the vertical plane of the upstream separation line(s)
(but not necessarily on the surface of the building itself). To decide
whether an arbitrary point (x,y,z) downstream of this plane is within the
14
-------
TABLE 1. EXPERIMENTAL CASES
Case No.
1
2
3
4
5
6
7
8
9*
10
11
12
13
14
15
16
17
17a
18
19*
20
21
22
23
24
25*
26*
27*
28
29
30
VHb
0.0
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.5
1.5
1.5
1.5
1.5
1.5
1.5
2.5
1.5
1.5
1.8
1.8
1.8
1.8
1.8
1.8
1.8
2.15
2.15
2.5
2.5
DS/HS
CO
0.052
0.052
0.052
0 052
0.052
0.052
0.052
0.021
0.021
0.017
0.017
0.042
0.042
0.042
C.042
C.042
C.025
C.042
(.042
(.035
0.059
0.059
0.091
0.091
0.091
0.091
0.076
0.076
0.065
0.065
VUs
w • —
0.7
0.7
1.5
1.5
2.2
4.0
4.0
1.5
8.4
0.4
0.4
0.4
0.4
0.7
0.7
1.5
1.5
1.5
2.2
0.7
0.7
0.7
0.7
0.7
0.4
0.4
0.7
0.7
0.7
0.7
ps/pa
1.0
1.0
0.5
1.0
0.5
1.0
1.0
0.5
1.0
1.0
1.0
0.5
1.0
0.5
1.0
0.5
1.0
1.0
0.5
1.0
1.0
1.0
0.5
1.0
0.5
1.0
0.5
1.0
0.5
1.0
0.5
Fr
oo
CD
5.8
oo
13.0
00
oo
33.4
00
00
CO
n.o
oo
5.8
oo
5.8
oo
oo
13.0
00
00
00
4.5
oo
4.2
oo
4.2
oo
4.2
oo
4.2
*No concentration measurements.
15
-------
cavity, we place a point source of tracer in the flow at this point and
answer the question: does any of the tracer eventually touch the building
surface? If it does, then this point is inside the cavity, if not, then
it is outside the cavity. This definition leads to a bubble boundary ABCDEA
in Figure 1; the outer edge of this cross section of the cavity is coincident
with the downstream reattachment line.
Whereas this definition may be untenable mathematically, it is useful
conceptually and is experimentally measurable. At various downwind positions
in the vertical plane along the building mid section (y/H. = 0), a smoke
source was raised in the vertical to a point where no smoke could be seen
recirculating back to the base of the building. These vertical positions
were used to define the vertical boundary of the leeward cavity region.
The building wake envelope was determined from observations of the maximum
vertical spread of smoke that was emitted from a source within the cavity
region. The lateral cavity region and wake envelope boundaries were
similarly determined in the horizontal plane halfway between the base and
top of the building (z/Hb = 0.5).
Phase II: Concentration Measurements
For all cases except as noted in Table 1, concentration measurements were
taken. Ground-level concentration measurements along the plume center-line,
downwind to 15 building heights, were taken. Vertical concentration pro-
files were measured near the point where the maximum ground-level concentration
was found. We selected this position for the vertical measurements, hoping
that it was far enough downwind to result in a profile representative of
the building effects on the vertical plume spread and that it would also
permit an easy determination of the plume centerline height. The plume
centerline height was defined a the position of maximum concentration in the
vertical profile since for all ;levated stack cases this position was found
to be well above ground level.
The ground-level measurements were taken at a position 0.025 m above the
wind tunnel floor. (This was necessary to avoid the roughness slats.) This
vertical displacement of the ground-level concentration measurements shoiild
have little significance, although some local variability in measurements near
the slats was found.
16
-------
Grourd-level measurements were limited to 15 building heights downwind
fron the building. This region should be adequate for analysis of the building
wake effect, since the vigorous turbulence in the building wake should have
decayed to near background levels within this distance. Turbulence intensity
measurements reported by Peterka and Cermak (1975) in the lee of several dif-
ferent model buildings showed this to be true.
For Case Mo. 17 (building removed), additional vertical and lateral mea-
surements were taken for the purpose of characterizing the background dis-
persion in the simulated atmospheric boundary layer. Concentration profiles
were measured at distances of 5, 10, and 15 building heights downwind. On a
1:200 scale, these positions represent full-scale distances of 250 m, 500 m,
and 750 m downwind fron; the source.
Phase III: Measurements Farther Downstream
Preliminary analysis of the data gathered in Phase II suggested a need
for concentration mappings to allow a more thorough examination of the building
wake effects. Case No. 1 (Hs/Hb = 0) and Case Mo. 17 (Hs/Hb = 1.5) were
selected as representing strong and moderate building wake effects. For these
cases, additional vertical and lateral profiles were taken at downwind positions
of 5, 10, and 15 buildings heights.
There were definite advantages to including some data in the far wake
region, "he experimental arrangement (building located at 9.0 m downwind
from the ''ortex generators), however, did not permit measurements beyond 20
building heights. The building was thus moved 2.5 m upwind closer to the
vortex generators, to a position where the equilibrium state of the boundary
layer was somewhat questionable. However, since the building-induced
turbulence was the dominating influence in this region, this arrangement was
felt to be acceptable; it extended the examinable region in the lee of the
building to 30 building height:,. For conditions of Case Nc. 1, Case No. 17,
and an additional Case No. 17a (similar to Case 17 except with the stack
height raised to 2.5 building heights), ground-level measurements to 30
building heights were taken. Vertical and ground-level lateral profiles at
downwind distances of 15 and 3C building heights were taken for Case No. 1
(Hs/Hb= 0).
17
-------
SECTION 4
RESULTS
As described in the previous section, 30 cases were examined. For
24 of the cases, concentration profile; were measured at ground level under
the plume centerline, and vertic. 1 prcciles were measured near the position
of maximum ground-level concentr.ition. Photographs of the smoke plumes were
taken for all cases. Complete results for Phase I and Phase II are presented
for each individual case in the /ppendix. Discussion and analysis of these re-
sults and presentation of all ad( itional results follow in this section. To
aid the reader and to eliminate continuous referral to Table 1, the pertinent
stack parameters are listed in parenthesis after mention of each case number,
i.e., (Hs/Hb, Ds/Hs, Ws/Us, ps/pa).
PHASE I; OBSERVATIONS OF SMOKE PLUMES
Figures 5 and 6 prese it the cavity boundary and wake envelope measure-
ments in both the vertical and horizontal planes of the building. The
cavity size in both planes was approximately 3.0 building heights in extent
downwind from the leeward edge of the building. The maximum vertical and
lateral extant of the cavity region was approximately 1.5 building heights
and was found to occur midway between the leading edge of the building and
the leeward end of the cavity. The envelope is slightly larger in the lateral
plane. A summary of the observations from the smoke visualization follows
below. Photographs of the vertical plume spread are presented in the Appendix.
For the ground-level source, Case No. 1 (0, «, --, 1), an instantaneous
spreading of the effluent to fill the wake in both the vertical and horizontal
planes was observed. This resulted from the strong vertical and horizontal
recirculation within the cavity region. For the low stacks (H /H. < 1.5) with
insufficient effluent momentum to escape the cavity (Case Nos. 2 through 6, 9_,
and 11 through 14), at least partial vertical mixing of the plumes into the
wake cavity was observed. Spreading ir the horizontal plane, however, was
much less rapid than was observed for the ground source. Case Nos. 7, 8, and
10 also had stack heights less than 1.5 H. , but, in these cases, the effluent
speed was sufficient for the plume to escape the cavity. The major en-
hancement of the vertical spread of the plume was due primarily to the un-
steadiness of the flow withir the recirculating cavity region.
For the cases where the effective stack height was above the cavity,
there was no entrainment into the cavity, but enhanced vertical dispersion
was still observed. Enhancement of dispersion in the horizontal plane was
again observed to be minimal. The amount of enhanced vertical plume spread
was observed to decrease with increasing effective stack height. The plumes
18
-------
I
N
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
y/Hb = O
• ENVELOPE; Uoo = 4.3 m/sec
• ENVELOPE; Uoo = 2.3 m/sec
O CAVITY ; Uoo:= 4.3 m/sec
D CAVITY ; U^ = 2.3 m/sec
\
V _
\
V
\ a
0.2
0.6
1.0
x/Hb
1.4
1.8
2.2
2.6 3.0
Figure 5. Vertical wake cavity and envelope Measurements.
-------
2.6
2.4
2.2
2.0
1.8
1.6
1.4
ja
X
*> 1.2
1.0
0.8
0.6
0.4
0.2
= 25 cm
z/Hb = 0.5
A ENVELOPE; U00 = 4.3 m/sec
• ENVELOPE; U^ = 2.3 m/sec
A CAVITY ; U^ = 4.3 m/sec
O CAVITY ; LU = 2.3 m/sec
N O
\
\
\
\
\
\
\
-U
0 0.2 0.6 1.0 1.4
x/Hb
1.8
2.2
2.6
3.0
Figure 6. Lateral wake cavity and envelope measurements.
-------
from the most elevated sources (H /H. = 2.15, 2.5) were not affected by the
building until the plume naturally spread downward into the wake region. At
these downwind distances, the turbulence had significantly decayed from that
observed in the cavity of the building. Thus, the overall effects of the
wake interactions on the vertical spread of these plumes were smaller.
For al ! cases, an increase in the effluent speed resulted in an increased
plume rise. The effluent speed for Case No. 7 (1.2, 0.05, 4, 1) was selected
by varying the effluent speed to determine the critical value for which the
plume avoided immediate entrainment into the cavity region. A similar
determination was conducted with a smaller diameter stack for Case No. 10 (1.2,
0.02, 8.4, 1). The necessary increase in stack effluent velocity to provide
sufficient olume rise resulted in nearly equivalent momentum fluxes,
Maintaining a ratio of effluent speed to wind speed at stack top of 3:2
was found to avoid aerodynamic downwash of the plumes behind the stacks. For
the cases with lower speed ratios (W_/U = 0.7, 0.4), stack downwash was clearly
o o
observed. It was even greater if the effluent density was decreased. A de-
crease in density resulted in a smaller momentum flux, thus, a smaller im-
mediate plume rise. No effects from changing only the stack diameter could
be clearly observed. Apparently, any change in momentum flux was offset by
a change in the stack wake influence.
PHASE II: CONCENTRATION FIELDS
The ground -level concentration profiles show the overall effects of the
building upon plume dispersion fo- a variety of source characteristics.
Vertical concentration profiles provided data to define the plume center line
height and the vertical plume spread. Comparisons between the measurements
made with the building in place and those for the isolated stack (building
removed) are used to define the building wake effect.
Plume Rise
Table 2 summarizes the evaluation of the plume rise estimates from
isolated stacks based on the following equations. Plume rise is composed
of a momentum term Ah , and a buoyancy term Ah., such that the total rise
is (Briggs, 1975) m D
Ah =
(Ahb)]
where
Ah - f 1 >,]1/3
m t^-J T
1/3 2/3
Ahb= (1.6F I x ' )/U ,
2/3 x V3
« !
21
-------
6=1/3+ us/ws = entrainment coefficient,
and
= gwc
pa'ps
buoyancy flux.
The downwind distance to final rise xf was estimated by the equation of Bn'gqs
(1971): f
= 3.5x*,
where
x* = 14 F5/8, for F less than 55 (mV3), and
x* = 34 F2/5, for F greater than or equal to 55 (m4s~3).
TABLE 2. PLUME RISE FROM THE ISOLATED STACKS
Case No. (Hs,°s,Ws,ps)
Hb Hb Us 'a
4 (1.2,0.052,1.5,1.0)
17 (1.5,0.042,1.5,1.0)
5 (1.2,0.052,1.5,0.5)
18 (1.5,0.042,1.5,0.5)
7 (1.2,0.052,4.0,1.0)
8 (1.2,0.052,4.0,0.5)
10 (1.2,0.017,0.4,1.0)
x
Hb
3
6
3
6
10
10
10
xf
Hb
2.7
2.7
__
'>.0
3Ds Ws
HbUs
0.28
0.28
0.28
0.28
0.75
0.75
0.63
*hm
Hb
0.21
0.27
0.17
0.21
1.1
0.87
1.2
Ahb
Hb
0.16
0.16
_
0.45
Ah
Hb
est.)
0.21
0.27
0.21
0.23
1.1
0.9
1.2
Ah
Hb
(obs.)
0.1-0.3
0.0-0.2
0.0-0.2
0.0-0.2
0.8-1.0
0.8-1.0
0.8-1.0
-------
The estimated plume rise was in genera' agreement with that observed in all
cases. Case Nos. 7 and 10 demonstrate that a cutoff position (final rise) for
estimating plume rise due to the initial momentum of the source is needed. It
does appear, however, that the maximum plume rise for these nonbuoyant sources
can be roughly ostimated by the generally applied rule of thumb, 3 D W /U
(Briggs, 1969).
The effect of the building upon plume rise was evaluated from the vertical
concentration profiles (see Appendix). The analysis was limited because only
one vertical profile was taken in most cases. Table 3 summarizes the effect
of the building wake upon the plune centerline height (vertical position of
maximum concentration). For most cases the plume centerline determined by
maximum concentration was found to be clearly defined because the profiles
were taken close to the source whore the maximum was pronounced.
Only Case Nos. 7 (1.2, 0.05, 4, 1), 8 (1.2, 0.05, 4, 0.5), and 10 (1.2,
0.02, 8, 1) afforded the opportunity to clearly evaluate plume rise, because
for all other cases the plume rise was minimal. At a position of 10 building
heights downwind, the plume rise in the wake of the building was found to be
less than two-thirds that found for the isolated stack. This reduction was,
of course, a result of increased entrainment of the plume by the building wake.
A change of the plume entrainment constants used in the plume rise model could
conceivably account for the reduction, but further studies are needed. The
lowering of the plume centerline height may also be the result of a general
down-drafting of the plume in the immediate wake of the building. The other
cases, although not having significant plume rise, did indicate a slight re-
duction of the plume centerline height in the wake of the building. In those
isolated stack cases where the velocity ratio W /U was less than 1.5, the
plume centerline height was found to b«; lower than the source height as a
result of stack downwash.
Characterization Of Wind Tunnel Dispersion
Vertical concentration profiles for the isolated stack of Case No. 17
(1.5, 0.04, 1.5, 1) were measured at 5, 10, and 15 building heights downwind,
and were usi?d in characterizing dispersion in the simulated atmospheric
boundary layer. Lateral concentration profiles at the height of the plume
centerline were also made at these downwind positions. Case No. 17 was
selected because its plume height was average for all the cases examined and
no stack downwash effects were observed. Figures 7 and 8 present the
horizontal and vertical concentration profiles and their estimated Gaussian
distributions, expressed as,
XUrHb
2
1
2
z+H
23
-------
TABLE 3. SUMMARY OF EFFECT OF BUILDING ON PLUME RISE
Case No.
1
2
3
4
5
7
8
10
11
12
13
14
15
16
17
18
2C
21
22
22
24
28
29
30
H< Dc W^ PC :
P TJ ii ! Longitudinal posi
"b % us pa J of vertical orofi
(x/Hb)
(0.0,-, — ,1.0)
(1.2,0.052,0.7,1.0)
1.2,0.052,0.7,0.5)
1.2,0.052,1.5,1.0)
1.2,0.052,1.5,0.5)
(1.2,0.052,4.0,1.0)
(1.2,0.052,4.0,0.5)
(1.2,0.021,8.4,1.0)
(1.5,0.017,0.4,1.0)
(1.5,0.017,0.4,0.5)
(1.5,0.042,0.4,1.0)
(1.5,0.042,0.4,0.5)
(1.5,0.042,0.7,1.0)
(1.5,0.042,0.7,0.5)
(1.5,0.042,1.5,1.0;
(1.5,0.042,1.5,0.5)
(1.8,0.035,0.7,1.0)
(1.8,0.059,0.7,1.0)
(1.8,0.059,0.7,0.5)
(1.8,0.091,0.7,1.0)
(1.8,0.091,0.7,0.5)
(2.15,0.076,0.7,0.5)
(2.5,0.065,0.7,1.0)
(2.5,0.065,0.7,0.5)
3
3
3
3
3
10
10
10
3
3
3
3
3
3
6
6
8
8
8
8
10
10
10
10
tion Vertical position of
le maximum concentration
Isolated Stack Building
(z/Hb) (z/Hb)
0.0 0.0
1.0 - 1.2 1.2 - 1.4
1.0 - 1.2 1.1 - 1.3
1.3 - 1.5 1.1 - 1.3
1.2 - 1.4 1.1 - 1.3
2.0 - 2.2 1.6 - 1.8
2.0 - 2.2 1.4 - 1.6
2.0 - 2.2 1.4 - 1.6
1.1 - 1.3 1.1 - 1.3
1.1 - 1.3 0.8 - 1.0
1.1 - 1.3 1.1 - 1.3
1.0 - 1.2 1.1 - 1.3
1.3 - 1.5 1.1 - 1.3
1.3 - 1.5 1.1 - 1.3
1.5 - 1.7 1.3 - 1.5
1.5 - 1.7 1.3 - 1.5
1.5 - 1.7 1.2 - 1.6
1.9 - 2.1 1.5 - 1.7
1.7 - 1.9 1.5 - 1.7
1.7 - 1.9 1.6 - 1.8
1.4 - 1.6 1.5 - 1.7
1.9 - 2.1 1.8 - 2.0
2.3 - 2.5 2.3 - 2.5
2.3 - 2.5 2.3 - 2.5
24
-------
1.0
ro
0.8
0.6
I)
X
0.4
0.2
x/Hb z/Hb ay/Hb az/Hb
O 5 1.5
A 10 1.6
D15 1.6
0.42
0.7
1.0
0.41
0.7
0.9
GAUSSIAN MODEL FIT
-3.0
-2.0
Figure 7. Lateral concentration profiles taken through the plume centerline; Case No. 17 (1.5, 0.042, 1.5, 1.0),
isolated stack.
-------
x'Hb y/Hb ffy/Hb az/Hb
O 5 0 0.42 0.41
A10 0 0.7 0.7
D15 0 1.0 0.9
GAUSSIAN MODEL FIT
I
N
0.4 0.6
XUrHb2/Q
0.8
1.0
Figure 8. Vertical concentration profiles taken through the plume centerline;
Case No. 17 (1.5, 0.042, 1.5, 1.0), isolated stack.
26
-------
Standard deviations a and o were computed from the concentration distribu-
tions plotted on log-probability paper and then slightly adjusted to provide
a better fit to the lower half of the vertical profiles, since this was the
region of greatest interest.
The wind tunnel dispersion parameters are plotted along with the
Pasquill-Gifford curves for stabilities B, C, D, and E (Turner, 1970) in
Figure 9. Vertical dispersion within the wind tunnel boundary layer is
closest to stability C, slightly unstable conditions. Horizontal dispersion
is closer to stability D. However, the boundary layer flow within the wind
tunnel is not truly thermally unstable. A better description of the boundary
layer would be urban, neutral. Dispersion curves based on a diffusion ex-
periment in St. Louis by McElroy and Pooler (1968) (presented by Briggs, 1973)
provide a better comparison. The wind tunnel horizontal dispersion is closely
related to the reported experimental results under neutrally stable atmospheric
conditions. Note that consideration of the model scale is necessary since
the rate of dispersion is not a linear function of downwind distance. The
growth in plume spread was found to be well described by
°z/Hb = °y/Hb = °'115 (x/V
o
Isolated Stack Data Compared Hitn Gaussian Plume Model
The dispersion parameters (o's) were determined, as discussed above,
from Case 17 (1.5, 0.04, 1.5, 1). These same dispersion parameters were then
used in the Gaussian plume model to estimate the concentration profiles for
the other cases. These comparisons are shown in Figure 10. It can be seen
that the fits are exceptionally good, even for the highest stack (Case No. E9
(2.5, 0.065, 0.7, 1)).
Figures lla and b present some of the longitudinal ground-level profiles
measured downwind of the isolated stacks. No profiles from the tallest stacks
were included here because the ground-level concentrations were too close to
the laboratory background. For all the isolated stacks, the plume was visual-
ly observed to reach the ground only irtermittently (x/H. =15). A longer
averaging time would have resulted in riore significant values for these sit-
uations, and, perhaps, better agreement with the Gaussian model. Poorer re-
presentations by the model were found as the source height was increased;
this may be due partly to the insufficient averaging time and the increasing
significance of the background level.
A mich better evaluation could have been made in the region farther down-
wind, whtre ground-level concentrations would have been higher. The measured
concentrations for these longitudinal profiles, in contrast with those for the
vertical profiles, are at levels where the fluctuations in the background
concentration ere significant. Considering the above difficulties and the
good comparisons of the Gaussian model estimates to the measurements of the
27
-------
100
50
0)
««.
b
20
10
't WIND TUNNEL; 1:200 SCALE
A WIND TUNNEL; 1:100 SCALE
0.1
100
50
0)
E
N
to
20
10
0.2
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x, kilometers
Figure 9. Estimated wind tunnel dispersion parameters compared with Pasquill - Gifford
values (Turner, 1970).
-------
4.0 «-r
3.5'
CASE NO.
O 2(1.2,0.052,0.7,1.0)
D 4(1.2,0.052, 1.5,1.0)
A 7(1.2,0.052,4.0, 1.0)
18(1.5, 0.042, 1.5, 0.5)
22(1.8,0.059,0.7,0.5)
A 29(2.5, 0.065, 0.7, 1.0)
GAUSSIAN MODEL ESTIMATE:
DERIVED FROM CASE NO. 17
r;, , , i , , . i i . , , . I . . i , I . , . , I , . , , i , , . I i i . .
0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5
XlUrHb2/Q
Figure 10. Vertical concentration profiles for isolated stack. In this and following
legends, He/Hb identifies the presumed effective stack height as determined from
analysis of vertical concentration profiles at position, x/Hb (see table 3).
29
-------
a
0.20
0.175
0.15
0.125
I I I I I I I I 1 1 ' I I I
CASE NO.
O 3(1.2,0.052,0.7,0.5)
014(1.5,0.042,0.4,0.5)
A 5(1.2,0.052, 1.5,0.5)
• 16(1.5,0.042,0.7, 0.5)
- •18(1.5,0.042, 1.5,0.5)
A 8(1.2,0.052,4.0,0.5)
CM
£ 0.10
i-
z>
x
0.0'5
0.05
0.025
•GAUSSIAN MODEL ESTIMATEP
CT'S DERIVED rROM CASE NO. 17
- O
OLLUQ
9.0
12.0
15.0
x/Hb
0.20
0.175 -
He/Hh x/Hb
O 2(1.2,0.052,0.7,1.0)
D 13(1.5, 0.042, 0.4, 1.0)
A 4(1.2, 0.052, 1.5, 1.0)
• 15(1.5,0.042,0.7, 1.0)
17(1.5,0.042, 1.5, 1.0)
7(1.2,0.052,4.0, 1.0)
GAUSSIAN MODEL ESTIMATE:
DERIVED FROM CASE NO. 17
0
9.0
12.0
15.0
x/Hb
Figure 11. Longitudinal gr( und-level concentration measurements downwind from
isolated stacks.
30
-------
vertical irofiles, dispersion downwind from the isolated stack is considered
to be well represented by the estimated dispersion parameters.
The Effects of The Building
Figures 12 through 14 present all the longitudinal ground-level concen-
trational profiles taken in the lee of the building. The longitudinal profiles
are grouped and presented here to allow for a simple comparison to be made
between the situations influenced by the building wake. For a case-by-case
comparison between the situation with the isolated stack and the situation
with the building in place, see the Appendix.
Note that for the ground source, Case No. 1 (0, °°, -, 1), a point is
reached where ground-level concentrations were lower than those from the ele-
vated stacks (See Figure 12). This is distinctly different from what occurs
from sources in the absence of any building wake or terrain influences. For
the ground source, greater enhanced dispersion occurs in both the vertical
and lateral direction, which results in the lower concentrations downwind.
This is in good agreement with the observations of the smoke plumes as reported
in Phase I. In Figures 12 through 14 the effective plume height H is the
position of maximum plume concentration as determined from the vertical pro-
files taken at distance x as reported in the caption.
For all the elevated stack cases (Figures 12 through 14), the positions
of maximum concentration are much closer to the source than were found down-
wind from the corresponding isolated stacks (Figures 11 a and b). Also,
ground-level concentrations are significantly higher in the wake of the build-
ing. These results are also in agreement with the observations made in Phase
I. The building wake has significantly enhanced the vertical plume spread.
A quantification of the enhancement is described below.
Modified Gaussian Model
A simple model (Huber and Snyder, 1976) was developed to account for the
enhanced dispersion found in the v/ake of this building. The dispersion
parameters are of the form:
a'(x) = 0.7Hb + 0.067(x-3Hb), for S^x/H^lO, and
o'(x) = a(x+S) for x/Hb>10,
where a(x) = dispersion parameter in absence of building
effects at downwind distance x,
o'(x) = enhanced dispersion parameter (with building
effects ) ,
and S = virtual source location.
31
-------
0.6
OJ
0.5
0.4
-------
00
0.6
0.5
0.4
0.3
0.2
0.1
*" A
&*
T
I
T
o~~~^o^ o
CASE NO.
O 12(1.5,1X017, 0.4^0.51
D 3(1.2, 0.052, 0.7, 0.5) T
A 5(1.2, 0.052, 1.5, 0.5) \
• 14(1.5,0.042,0.4,0.5)
• 16(1.5,0.042,0.7,0.5)
A 18(1.5^0.042, 1.5.0.5)
O 8(1.2, 0.052, 4.0, 0.5)
He/Hb, x/Hb:
i i i I ill i i i I I i II ill I I I I I 1 I 1 I i I I I 1 I I I
_
1.2
1.2
1.2
1.2
1A.
1.6
^
3
3
3
3
6
10
i-U
1.5,
3.0
4.5
6.0;
7.5
x/Hb
9.0
10.5[
12.0
13.5
15.0
Figure 13. Longitudinal ground-level concentration measurements in the lee of the building; slightly buoyant sources
with Hs/Hb<1.5.
-------
T
0.15
CJ
a0.1
0.05
CASE NO.) I
O 20(1.8, 0.035, 0.7, 1.0)
D! 2f(1.8, 0.059, 0.7, 1.0)
A122(1.8, 0.059, 0.7, 0.5)
• 24(1.8,0.091,0.7,0.5)
7123(1.8,0=091,0.7, 1.0)
• (28(2.15,0.076,0.7,0.5)
V|(29(2.5, 0.065,0.7, 1.0)1
[30(2.5, 0.065, 0.7, 0.5)j
He/Ufa
Figure 14. Longitudinal ground-level concentration measurements in the lee of the building; Hs/Hb>1.5.
-------
The above equations were derived to provide best agreement with the
longitudinal ground-level profiles for the ground source (Figure 15), with
enhancement of both the vertical and lateral dispersion parameters assumed.
The virtual source location was determined by matching the above equations at
10 building heights downwind where the enhanced rate of dispersion has likely
ceased, leaving only a residual wider plume. For the conditions of this study,
the virtual source location was found to equal eight building heights; S = 8H^.
Figures 16 and 17 present the vertical and lateral concentration profiles
for the ground source. Estimates using the modified Gaussian model for the
ground source data were found to be good, with slightly higher centerline
values estimated near the surface at x/H. = 5.
For elevated sources, concentration estimates are based on modifying only
the vertical dispersion parameter because a significant increase in lateral
spread appeared to be absent. This results from the vertical oscillations in
the disturbed flow over the building sweeping above the building as expected
while the lateral oscillations sweep laterally only near the building. Longi-
tudinal fround-level concentration profiles based on the modified Gaussian
model an presented in Figure 18 for various effective source heights, He/Hu.
These profiles were compared with the measurements found in Figures 12-14.
Agreement was very good for all except the most elevated cases where ground-
level concentrations were over-estimated. There was less building influence,
as expected, for the more elevated sources.
Vertical and lateral concentration profiles for elevated source, Case No.
17 (1.5, 0.042, 1.5, 1.0), are compared with the modified Gaussian model in
Figures 19 and 20. Profiles for this stack in the absence of the building
have already been presented in Figures 7 and 8. The vertical profiles (Figure
19) at the lower levels are found to be in agreement with the model estimates,
but the vertical spread at x/H. = 5 is overestimated; the data show that the
plume was contained below about two building heights, whereas the model pre-
dicts that the plume will reach three. The lateral profiles (Figure 20) taken
at the elevated levels are in very good agreement with the model estimates.
At ground level, the maximum concentrations are predicted quite well by the
model, but the horizontal widths of the plume are considerably underestimated.
Perhaps near the ground, influences upon the horizontal spread must be ad-
ditionally considered.
PHASE III: MEASUREMENTS TO 30 BUILDING HEIGHTS DOWNSTREAM
The longitudinal concentration profiles that were taken to examine the
region downwinc' to 30 building heights are presented in Figure 21. Model
concentration estimates both in the wake of the building and in the absence of
the building are also included in the figure. For the two elevated stacks,
only enhancement of the vertical plume spread was considered. Very good
agreement with the model was found for the ground source, Case 1, and Case 17
(1.5, 0.042, 1.5, 1.0). The use of an area-source model (Gifford, 1960),
-------
3.0
LJ
i r
2.5
2.0
O
D
I—B
GO
a
OJ
&
X
O CASE NO. 1; WITHOUT BUILDING i
C CASE NO. 1; WITH BUILDING
GAUSSIAN MODEL ESTIMATE:
ff/s DERIVED FROM CASE NO. 17
"a's ADJUSTED TO FIT WAKE
ENHANCEMENT
1.5
D
a
1.0
0.5
D
-^ D
D "•*•
-I
1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0
x/Hb
Figure 15. Longitudinal ground-level concentration measurements for ground source; Case No. 1.
-------
WITHOUT BUILDING
• x/Hb= 5
O x/Hb = 10
WITH BUILDING
Ax/Hb= 5
Ax/Hb = 10
• x/Hb = 15
GAUSSIAN MODEL ESTIMATE:
ff's DERIVED FROM CASE NO. 17
ADJUSTED ff's FROM CASE NO. 1
LONGITUDINAL MEASUREMENTS
0.2
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
XlUrHb2/Q
Figure 16. Vertical concentration measurements for ground source; Case No. 1.
37
-------
2.0
CO
00
1.6
GAUSSIAN MODEL ESTIMATE:
a 's DERIVED FROM CASE NO. 17
ADJUSTED
-------
w
10
1.5; 3.0 4.5
7.5! 9.0 10.5 12.0 13.5 15.0
0.05! -
Figure 18. Longitudinal ground-level concentration profiles for elevated sources based on the Gaussian model using an
adjusted vertical a from Case No. 1.
-------
-5.5
3.0
2.5
2.0
-Q
X
IM
1.5
1.0
0.5
n
I
\ V WITH BUILDING
° \\ 0 x/Hb=5
\N\ • x/Hi -10
\ V 0 x/Hb=15
° \ \\
\ \ X GAUSSIAN MODEL ESTIMATE:
1 \ ^V
\ \ \ API II ICTCr\ \/CDT"ir*A 1
j » \ ^. AUJUo 1 tU VbK I IUAL ,
0 an^. \ \ ^ a's FROM CASE NO. 1
\ \ ^Xx
•\ \ Nx
\ \ xx
— 0^1 o\ x\ —
\ \ ^ l
°\m \ ° \ i
^ : \
I • \ \
D\ b |
I * /
P n> / o
1 ,^ /
— P • / —
I J" /
ofy i /o
1 ^ /x
D / H /
- i /• x -
,0 « O/
1 [• /
d o te /
M H ' 1
'lo0V' 1
0.05 0.15 0.25 0.35
XUrHb2/Q
0.45
0.55
Fiijure 19. Vertical concentration measurements; Case No. 17 (1.5, 0.042. 1.5, 1.0).
40
-------
0.5
0.4,-
0.3 -
I
k.
D
X
0.2 -
0.1 -
GAUSSIAN MODEL ESTIMATE: |
ADJUSTED VERTICAL a^ FROM
CASE NO. 1 i
z/Hb=1.5
z/Hb =
-3.0
Figure 20. Lateral concentration profiles; Case No. 17 (1.5, 0.042, 1.5, 1.0).
-------
ro
.D
I
a 0.1
GAUSSIAN MODEL ESTIMATE:
aj's DERIVED FROM CASE NO. 17
ADJUSTED oi's FROM CASE NO. 1
AREA GROUND SOURCE MODEL,
CASE No. 1: Hs/Hb = 0
o WITHOUT BUILDING
O WITH BUILDING
CASE No. 17: Hs/Hb = 1.5
• WITHOUT BUILDING
WITH BUILDING
CASE NO. 17a: Hs/Hb = 2.5
• WITHOUT BUILDING 2.6
WITH BUILDING
100
Figure 21. Longitudinal ground-level concentration measurements. Phase
-------
was found to provide a good estimate of the ground-level concentrations when
K=l. For Case 17a with H /H. = 2.5, an overestimation of concentration was
found both in the wake of the building and in the absence of the building.
The background dispersion parameters were estimated from data for a lower
stack (H /H. = 1.5), which may be the cause of the difference. The overest-
imate of concentration in the wake of the building is an indication, as ex-
pected, that the building wake has less effect as the stack height is in-
creased.
Figure 21 provides a good overview of the building wake effects on short
stack effluents. For the ground-level source, the building wake greatly in-
creased the plume spread (horizontal and vertical) in the immediate lee of
the building, thus resulting in decreased ground-level concentrations from
those that occurred in the absence of the building. Farther downwind, the
plume dispprsion was controlled by the background turbulence. Therefore, the
measured concentrations slowly converge to values that occured in the absence
of the building. For the elevated sources, the major building wake effect
was that of an increased vertical plume spread, which caused the point of
maximum ground-level concentration to shift upwind. For H /H. = 1.5, this
effect caused the absolute maxirrum concentration to increase by a factor of
three over that which occurred -'n the absence of the building. A similar,
somewhat decreased effect was fc>und for the situation with H /H, =2.5. A
convergence of the ground-level conoentratior, for the elevated stacks, to
the value measrred in the absence of the building was also found to occur in
the far wake region. However, the downwind position of convergence appears
to be somewhat farther downstream.
For the ground source (Case No. 1), vertical and lateral concentration
profiles were taken at 15 and 30 building heights downwind. These data and
model estimates are presented in Figures 22 and 23. Near the ground and close
to the plume centerline, the model concentration estimates at 15 building
heinhts downwind of the building were found to be slightly overestimated, but
at :.Q building heights downwind from the isolated stack, the model slightly
underestimated concentrations. The lateral profiles demonstrate that for all
situations the model overestimates the lateral plume spread even though con-
centration estimates near the plume center!ine are well estimated. The
reasons for this are not apparent since, for the earlier profiles, the lateral
plume spread was well modeled. Perhaps the profiles taken in Phase III were
influenced differently by a lateral inhomogeneity in the turbulent boundary
layer since the profiles were measured at a position farther from the sources
and the building was closer to the vortex generators.
43
-------
O x/Hb = 15; WITHOUT BUILDING
Ox/Hb = 15; WITH BUILDING
& x/Hb = 30; WITHOUT BUILDING
= 30; WITH BUILDING
GAUSSIAN MODEL ESTIMATE: —
tr's DERIVED FROM CASE NO. 17
ADJUSTED W's FROM CASE NO. 1
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
XUrHb2
Figure 22. Vertical concentration measurements for ground source; Case No. 1, Phase III.
44
-------
0.50
0.4S
0.40
Ox/Hb = 15; WITHOUT BUILDING
Dx/Hb = 15; WITH BUILDING
A x/Hb = 30; WITHOUT BUILDING
• x/Hb = 30; WITH BUILDING
GAUSSIAN MODEL ESTIMATE:
a's DERIVED FROM CASE NO. 17
ADJUSTED a's FROM CASE NO. 1
in
0.35
0.30
a 0.25
0.20
0.15
0.10
0.05
Figure 23. Lateral ground-level concentration profiles for ground source; Case No. 1., Phase III.
-------
REFERENCES
Briggs, G.A., 1969: Plume Rise, Critical Review Series, U.S. Atomic Energy
Comm., TID-25075, Nat. Tech. Infor. Serv., Springfield, VA, 81 p.
Briggs, G.A., 1971: Some Recent Analyses of Plume Rise Observations, Paper
No. ME 8E, Proc. Second Int. Clean Air Congress, ed. by H.M. Englund and
W.T. Beery, Academic Press, NY.
Briggs, G.A., 1973: Diffusion Estimation for Small Emissions, ATDL No. 79,
Atiros. Turb. and Diff. Lab., NOAA Envir. Res. Lab.., Oak Ridge, TN, May.
Briggs, G.A., 1975: Plume Rise Predictions, ATDL No. 75/15, Atmos. Turb. and
Diff. Lab., NOAA Envir. Res. Lab., Oak Ridge, TN, 46 p., June.
Britter, R.E., Hunt, J.C.R. anr Puttock, J.S., 1976: Predicting Pollution
Concentrations Near Buildings ; nd Hills, Corf, on "Systems & Models in Air
& Water Pollution", Inst. of Meas. & Control, London, Sept. 22-24.
Cermak, J.E., 1971: Laboratory Simulation of the Atmospheric Boundary Layer,
AIAA J., v. 9, no. 9, p. 1746-54, Sept.
Counihan, J., 1969: An Improved Method of Simulating an Atmospheric Boundary
Layer in a Wind Tunnel, Atmos. Envir., v. 3, p. 197-214.
Csanady, G.T., 1973: Turbulent Diffusion in the Environment, Geophys. and
Astrophys. Monographs, D. Re1del Pub. Co., Boston, MA, 248 p.
Davenport, A.G., 1963: The Relationship of Wind Structure to Wind Loading,
Paper 2, Proc. Conf. on Wind Effects on Bldgs. and Structures, Nat. Phys.
Lab., June, HMSO, London, 1965, p. 54-102.
Evans, B.H., 1957: Natural Air Flow around Buildings, Texas Engr. Exp.
Station Res. Rpt. 59, Texas A & M College, College Station, TX.
Gifford, F.A., Jr., 1960: Atmospheric Dispersion Calculations using the
Generalized Gaussian Plume Model, Nucl. Saf., v. 2, p. 56-9.
Golden, J., 1961: Scale Model Techniques, M. S. Thesis, College of Engr.,
Nev York Univ., May.
Halitsky, J., 1968: Gas Diffusion Near Buildings, Meteorol. and Atomic Energy,
(ed. D.H. Slade), TID-24190, U.S. Atomic Energy Comm., Sect. 5-5, p. 221-55.
46
-------
Halitsky, J., 1969: Validation of Scaling Procedures for Wind Tunnel Model
Testing of Diffusion Near Buildings, Ph.D. Diss., Rpt. No. TR-69-8, New York
Univ., NY, NY.
Harris, R.r., 1968: Measurement of Wind Structure at Heights up to 598 feet
above Ground Level, Symp. Wind Effects on Buildings and Structures, Lough-
borough Univ. Tech. (Dept. of Transport Technology), England.
Hoult, D.P., 1973: Simulation of Buoyant Pollutants in the Atmospheric
Boundary Layer, Flow Studies in Air and Water Pollution, Am. Soc. Mech. Engrg.,
NY, NY.
Hoult, D.P. and Weil, J.C., 1972: Turbulent Plume in a Laminar Cross Flow,
Atmos. Envir., v. 6, no. 8, p. 513-32, Aug.
Hubers A.M. and Snyder, W.K, 1976: Building Wake Effects on Short Stack
Effluents, Proc. 3rd Symp. on Atmos. Turb., Diff. and Air Quality, Oct. 26-29,
Raleigh, NC, Am. Meteorol. Soc., Boston, MA.
Huber, A.H., Snyder, W.H., Thompson, R.S., and Lawson, R.E., Jr., 1976: Stack
Placement in the Lee of a Mountain Ridge: A Wind Tunnel Study, Envir. Prot.
Agcy. Rept. No. EPA-600/4-76-047, Res. Tri. Pk., NC, Sept., 45 p.
Lin, J.T., Liu, H.T., Pao, Y.H., Lilly, O.K., Israeli, M. and Orszag, S.A.,
1974: Laboratory and Numerical Simulation of Plume Dispersion in Stably
Stratified Flow over Complex Terrain, Envir. Prot. Agcy. Ppt. No. EPA-650/4-
74-044, 70 p., Nov.
McElroy, J.L. and Pooler, F., Jr., 1968: St. Louis Dispersion Study, Vol. II-
Analysis, Nat. Air Poll. Control Admin. Pub. No. AP-53, Cincinnati, OH.
Meroney, R.N., 1971: Gaseous PIjme Diffusion about Isolated Structures of
Simple Geometry, Rpt. No. CER71-72RNM19, Colo. State Univ., Ft. Collins, CO,
13 p., Dec.
Meroney, R.N. and Yang, B.T.5 1971: Wind Tunnel Study on Gaseous Mixing Due
to Various Stack Heights and Injection Rates Above an Isolated Structure, Rpt.
No. CER71-72RNM-BTY16, Colo. State Univ., Ft. Collins, CO., (also AEC Rpt. No.
COO-2053-6).
P'terka, J.A. and Cermak, J.E., 1975: Turbulence in Building Wakes, 4th Intl.
Cjnf. on Wind Effects on Buildings and Structures, Sept. 8-12, London, England
(also Rpt. No. CER74-75JAP-JEC34, Colo. State Univ., Ft. Collins, CO).
Robins, A.G. and Castro, I.P., 1977a: A Wind Tunnel Investigation of Plume
Dispersion in the Vicinity of a Surface Mounted Cube, I. The Flow Field,
Atmos. Envir., v. 11, no. 4, p. 291-7.
Robins, A.G. and Castro, I.P., 1977b: A Wind Tunnel Investigation of Plume
Dispersion in the Vicinity of a Surface Mounted Cube, II. The Concentration
Field, Atmos. Envir., v. 11, no. 4, p. 299-311.
47
-------
Smiti, E.G., 1951: The Feasibility of using Models for Predetermining Natural
Ventilation, Res. Rep. No. 26, Tex. Engng. Exp. Stn., Texas A & M College,
College Station, TX.
Snyder, W.H., 1972: Similarity Criteria for the Application of Fluid Models
to the Study of Air Pollution Meteorology, Bound. Layer Meteorol., v. 3, no. 2,
p. 113-34.
Snyder, W.H., 1979a: The EPA Meteorological Wind Tunnel: Its Design, Con-
struction, and Operating Characteristics, Envir. Prot. Agcy. P.pt. No. EPA-600/
4-79-051, Res. Tri. Pk., NC, 78 p., Sept.
Snyder, W.H., 19795: Guideline for Fluid Modeling of Atmospheric Diffusion,
Draft for Public Comment, Envir. Prot. Agcy. P.pt. No. EPA-450/4-79-016, Res.
Tri. Pk., NC, June, 172 p.
Snyder, W.H. and Lawson, R.E., Cr.t 1976: Determination of a Necessary Height
for a Stack Close to a Building - A Wind Tunnel Study, Atmos. Envir., v. 10,
no. 9, p. 683-91.
Turner, D.B., 1970: Workbook of Atmospheric Dispersion Estimates, Office of
Air Programs, Pub. No. AP-26, U.S. Envir. Prot. Agcy., Res. Tri. Pk., NC, Jan.
48
-------
APPENDIX
The complete set of data from Phases I and II are presented for each
case. Smoke was visually observed for 30 cases, while concentration measure-
ments consisting of longitudinal and vertical profiles were taken for 24 of
the cases. The effect of the building can be easily seen here since visual
observations and concentration neasurements were made both in the v/ake of the
building and in the absence of :he building. Comparisons of the longitudinal
profiles for the cases with the tallest stack heights show rather large
differences in maximum concentration. These results are due to very slight
influences of the building, causing the point of initial ground-level impact
to be moved closer to the source. Measurements farther downwind, at the point
of maximum concentration, would not show such large differences. Thus, data
^or these cases cannot be used to quantify the significance of the building
nfluence as can be done for the shorter stacks.
In a'l cases, the top and botton photographs of the smoke are with end
without the building, respectively. The exposure time for all photographs
was 4 seconds. To aid the reader, five parameters have been added in paren-
thesis following each case number, i.e., (Hs/Hb, DS/HS, WS/US, Ps/Pa> Frg).
The concentrations denoted as D and + represent measurements with and
without the building, respectively. In some cases, measured concentrations
are negative end lie outside of the I oundary of the graph. These situations
are a result if the background concei tration being over-estimated, as could
have been caused by a drifting backg ound during the measurement period.
49
-------
Figure A-l. Case No. 1 Smoke visualization (0, », —, 1.0, «)
50
-------
1.8
i.e
1 . 4 -t D
.f. --
.4 --
n
n
a
a
n
\
a
"** - \ v
P _: ^ °
. o -4- v n
a
a
D
— j_ p-p
-T— r- -T--}— -r T- i — \' ~n — i — r~ +-7-7
(a) Vertical profiles
L I_I_|..J_ I _L_.J ) L_J
1.5 2 E.. 5
. -L._|_l_L_L_L_(_J_J_ Jl L__h
3 3.. 5 4
3 -
£.75-
I
£.5-^1
£-25-;:J
2 -:
X
1.25-
1 -
\
a
\
(b) Longitudinal profiles
n,
O
0 p-l I- ' L| I I I L. I I I I I I I |
0 1.5 3 4,5 f,
\
_
I^|
n_
:i
j-r
a
! I I | i I
10.5 12 13.5
F gure A-2. Case No. 1 concentration measurements.
51
-------
Figure A-3. Case No. 2 smoke visualization (1.2, 0.052, 0.7, 1.0, »).
52
-------
3.5 --
£.5 r
1.5
13-
rJ
\
EXv
rT-T--rTT-~rr T IT
(a) Vertical profiles
_i
(-L-J-jJEj-J_.U.-l-|-J-U I I I I I I I LJ-L-I_[_'.U_I_L4 _L1_L -L-fJ_l_ _]_!_L I I I I LJ_L1_I
J .£5 .5 .75 1 1.25 1.5 1.75 ;• £.£R 3.S
.6
.55
i.1
I i i i i i !~rr "rrl i i i i i TT-TT T-rhrrrT-r ! i i i i r-hrrT-rr+-m-rii:~
(b) Longitudinal profiles =~
0 -1.5
a
a
-i
4.5, 6
_ i-l-L-L.|_LJ_'_l_L,| I I LJ_1. -|_I_I_LJ_ C _
7.5 ? 13.5 IE 13.5 15
x/Hb
Figure A-4. Case No. 2. concentration measurements.
53
-------
Figure A-5. Case No. 3 smoke visualization (1.2, 0.052, 0.7, 0.5, 5.8),
54
-------
(a) Vertical profiles
! I i | I I I I | I I I _)_1_1_LL. | I I I ! | I I I I | I I I I
0 .-:5 .5 .75 1 1. £5 1.5 1.75 Z £.£5 £.5 £.75 3
• € - _j M i i I ri i i i I i i i -
.55 -£
L_
.5 -E
. 45 -:-
,- D
.35 -
•2 __: „
(b) Longitudinal profiles E_
P
1.
rs
x .25
• 15 -';
. 05 -I ;~
0 P ' ' ' ' | I-L-LJ_i,|_L-L-Lj_l_p_L I M I i i | I I I I I I i i i i ,
0 1.5 3 4.5 € 7. - ^^^ ^
x/
12 13.5 15
Figure A-6. Case No. 3 concentration measurements.
55
-------
Figure A-7. Case No. 4 smoke visualization (1.2, 0.052, 1.5, 1.0, °°),
56
-------
3.5 —
'"I I I I I I I I I I I I I I I I T"H"TTTT"HrTT~r'
(a) Vertical profiles
2.5 -
0 _ I I I I I T 1 I I I I I I I | I I I 1 I I I I I I I I I I I I I I I
C .25 .5 .75 1 1.25 1.5 1.75 £ £.25 £.5 2.75
1.5 —
l_L_L._LL_L_L_i. t. ,1, ',,[ LL1.J. I j * ' j { ' I -I.--.I---I--J- !"
8 1.5 3 4.5 b 7.5 9 10.5 IZ 13.5 15
x/Hk
Figure A-8. Case No. 4 concentration measurements.
57
-------
Figure A-9. Case No. 5 smoke visualization (1.2, 0.052, 1.5, 0.5, 13.0)
58
-------
3.5 --
(a) Vertical profiles
.5 .75 1 1.25 1.5 1.75 2 2.25 £.5 8.75 3
D D
. € -'_) i i i i I i i i i i I 'i i m-hrr i i i I i i i ! H i n i i I i r i i i I M i i i I i i i
(b) Longitudinal profiles
=~3-
.U-J-l-l I...J.I ' I ..[. I I-I -U| I I I I I I I I I I I I I I I I I I I I I I I I p_|_l_L
3 4.5 € r.5 9 10.5 12 13.5 15
Figure A-10. Case No. 5 concentration measurements.
59
-------
Figure A-ll. Case No. 6 smoke visualization (1.2, 0.052, 2.2, 1.0, «)
60
-------
Figure A-12. Case No. 7 smoke visualization (1.2, 0.052, 4.0, 1.0, »)
62
-------
r~\~v~rT~!~\ i i i i I—r~r~rr~
"i"~l~
(a) Vertical profiles
i
*J . J
3 -
i: . 5 -
a
.!_
N
1.5 -
1 -
5 _
.1 _
_ a ~*"«^^
- >. ^^*_^
- o. ^^* -t-
- ^x^ ^^"^
- ^^* a "l"">x.
a •+
a^\ •+ ]
: /?I^^
4- --"a
-4- ^^ — ' a
- -»- a
"" j-*^^'*~ n '
: ^ /
- / *
-+- - O
- /°
"*i i i i 1 i iH i 1 i i i i | i i i i 1 i i i i 1 i i i i I i i i i i i
H
-i
^
!
—
~
":
"
—
—
—
-
"
—
"-
II 1 1 1 1 1 1 1 1 1
0 .135 .1 .15 .8 .25 .3 .35 .4 .45 .5
. 125 --
CD-
.075--
i.
Z3
X
.05 --
.025 —
I i I r i I i i i Til M i r~r~h rr-rH~ rr~r T~I I i M i i I i i i i i H i i i i I T
(b) Longitudinal profiles -
a
1. I I L_L_[_I I I I I I I I .L_l_l_|_Ll. Ul-|.J_l LJL1_|_I_L .III
1.5 3 4.5 ti 7.5 3
i i i i I i i
x/H.
3 10.5 12 13.5 15
Figure A-13. Case No. 7 concentration measurements.
63
-------
Figure A-14. Case No. 8 smoke visualization (1.2, 0.052, 4.0, 0.5, 33.4)
64
-------
3.5 --
3 -
£.5 --
-Q
N
, S ~~
i i i i i i i
"t~r~TT~r~l i i ri l~r r~rTh n"T"r~t~rr r'r4~r r"r~r
(a) Vertical profiles
D
d
a
i i 'i " i i i | i i i i [ i i i i [ i i i i | i i i i | i i i i | i i i i
.05 .1 .15 .2 .25 .3 .'35 .4 .45
i i i i i i i I i
a
• I J
; 125-
. 1 -
cx
— a v» a
jr a -
o
/ (b) Longitudinal profiles
D
/° :
a
~
'j
1 1 I 1 1 1 1 1 1 1 1 1 1 ! 1 1 1 1 1 I 1 1 1 1 I 1 1 I 1 1 1 1 1 1 1 1 1 1 II j | 1 1 1 1 1 1 1 1 , 1
ll5 3 4'. 5 t! "',S 9 10.5 13 13.5 1
x/H,
Figure A-15. Case No. 8 concentration measurements.
65
-------
Figure A-16. Case No. 9 smoke visualization (1.2, 0.021, 1.5, 1.0, °°)
66
-------
Figure A-17. Case No. 10 smoke visualization (1.2, 0.021, 8.4, 1.0, °°),
68
-------
3.5
£.5 --
N
I i i'i T~H"T~i~i~i~T t-rT J(--r-r-1 r 1 TTTT t
(a) Vertical profiles
1.5
0 I I I 'I I I I I I I I I I I I 1° I
0 .05 .1 .15
I I | I I I U| I -I I I | I I I I | I
.25 .3 .35 .4 .45
H
—I
.1
15
i i •: i I i r i i i I i M i i +TT~' ~H~rrrT~rh~i~rr~i I i i i M I i i i ' i I i i i~n+
ex
CM
ja.075--
. 05 - -
.025--
L -
0
(b) Longitudinal profiles
.-L-| I I I I I | I I I I I | M I I I | I 1, 1 I I | I I I I I [ I i i4i i | i i i i i | L i
1.5 3 4.5 t £Q5+- 9 10.5 IE
x/Hb
13.5
Figure A-18. Case No. 10 concentration measurements.
69
-------
Figure A-19. Case No. 11 smoke visualization (1.5, 0.017, 0.4, 1.0, ~)
70
-------
rrH~rr i i 1 i i i i+T-rrrtTT-rT+-nrnHTT~n-t-r r iT™f"rrTT-h-rrr +rrr'
3.5
(a) Vertical profiles
2.5 --
N
1.5 --
i ) -T~rr-t
(b) Longitudinal profiles =
—i
—i
Figure A-20. Case No. 11 concentration measurements.
71
-------
Figure A-21. Case No. 12 smoke visualization (1.5, 0.017, 0.4, 0.5, 11.0)
72
-------
3.5--
3 --
2.5 --
:N
2 --
N
1.5 --
0 -
-rt~rrT"H ill r'l'n i i I i rrr+n TTT I i i~i~H rr~rT+ rrr
ITT4 rrrr
(a) Vertical profiles
0+.
n
D .
E^
I I I | IT I I | I I I I |
0 .25 .5 .75 .1 1.25 1.5 1.75 2
i i i i i i i i i i i i i i i i
2.25 2.5 2.75 3
.45 - =
.4 -r
°; .35
CM
n
.3
.
~cf
S-
^ .25 -E
,2
. 15 -t
. 1
.05 -E
8
0
I I I I I I I I I I T I I I I I I I I I I I [ I I I I I I I I I I I I I I I I I I I I I I I I ! I I I I LJ
a
(b) Longitudinal profiles
'1 .
[ i I i i i i i I i i i i i i i i i i I i • rh i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i
1.5 3 4.S t. 7.5 9 10.5 12 13.5 15
x/Hk
Figure A-22. Case No. 12 concentration measurements.
73
-------
Figure A-23. Case No. 13 smoke visualization (1.5, 0.042, 0.4, 1.0, «,)
74
-------
3.5 --
(a) Vertical profiles
J
0 .£5 .5 .75 1
i i i i I i i i i i i i i i i j i i i | i i i i i i i i i i i i i
1.25 1.5 1.75 £ £.£5 c.5 £.75 3
.
-------
Figure A-25. Case No. 14 smoke visualization (1.5, 0.042, 0.4, 0.5, 5.8)
76
-------
3.5 --
-h~TT~r I n i i I M i i hrr~r r-Hrn T+TTTT-h m-fi r rH'T
(a) Vertical profiles
1 .5 - -
•I
.5 -4- s
Fx °
t4" n ~i
g |~i "f i i [ i I PI |. i i i i j i i i i j i i i i [ i i i i | i i i i | i i i i i i i i i | i i i i | i i ! i [ i i i r~|
0 .25 .5 .75 1 1.25 1.5 1.75 2 £.25 2.5 2.75 3
.6
.55
.5
.45
.4
O .35
OJ
•nf* '3
X .25
.2
. 15
. 1
.65
0
| | | | | I I I I I I I I I I I' I I I I I I I I I I I I I I I I MT1 I I I M I I I I I I I I I I I I C
(b) Longitudinal profiles
/
D -" a — . n
~ a
za
4.5
1.1 \ 1,-J li 1 i is J LI I LI LI I 111 ...Li. J.. J 1 J m t I. t I..!. 1,1 C* _
€ 7,5 9 10,5 12 13.5 15
Figure A-26. Case No. 14 concentration measurements.
77
-------
Figure A-27. Case No. 15 smoke visualization (1.5, 0.042, 0.7, 1.0, »)
78
-------
T-r+r-rrr-f T"rT-ri~rTTT-hrrrrl-T-i rr h"rrr
(a) Vertical profiles •
0 .25 .5 ."5
J-l I I |-- -L.L-L-[ I I I I | I I I I | I I I I | I I I I | I I I I | I I I I |
l.£5 l.5 1.75
2.25 2.5
. 3
.275
.25
.225 -F
.2 -E
^ •1^5 -E
N r
n:3 . 15 -t
^ .125
. 1
.075-t
.05
. 025 -
-i i i i I i i i M I rr i i i I i i i i i+Ti-rT~H""-TTTT I M i i i l'i i i i i I i i i r
= ,
i/
a
(b) Longitudinal profiles E
i < i i i r i i '. ; ; i i i i i i i i i i i i i i i i i i i i i t r
0 1.5 3 4.
€ 7.5 9
x/Hu
10.5 12 13.5 15
Figure A-28. Case No. 15 concentration measurements.
79
-------
Figure A-29. Case No. 16 smoke visualization (1.5, 0.042, 0.7, 0.5, 5.8)
80
-------
~rt TT"r~H~T Mill ~'~rr~+ T-I i i+nT7"!"
(a) Vertical profiles
3.5 --
2.5
1.5 --
0 _ 1 I I I I iT I I I I I I I I I
PTT I i i M idi i i i ii h i M i I i M i i I i i rrT"! n i~rH-TT-rr-rt-T-rTi-i |-
(b) Longitudinal profiles
4 _U_ '. J_'_|_l_L I I 1 4-L-L- L_! ±4 I I I I I I I I I I I I I I I I . .L L|_1_1_L T
=
l.'J 3 4.5 e 7.5 9 18.5 13 1 ^s
Figure A-30. Case No. 16 concentration measurements.
81
-------
Figure A-31. Case No. 17 smoke visualization (1.5, 0.042, 1.5, 1.0, »)
82
-------
4 -j
rv ~i n r+-rn-r-f- m'H VT r~ri~r r"r-rt~"rT T~T_J-
(a) Vertical profiles i".
3.5
g i i i i | i i i71 i i i i i [. i . L_l_j__l_ _l.j__|__
C .1 .Z .3 .4 .5
} r b
I I I I I I i I I I I I I I I I I i I I I i h~ r
(b) Longitudinal profiles =
0 nfll i |i i
P 1.5
-Lp-J-LI I | I I I I I | I i I I : | I i i i i | i i i L_l~._
r,5 3 10.5 12 13.5 15
Figure A-32. Cese No. 17 concentration measurements.
f-3
-------
Figure A-33. Case No. 18 smoke visualization (1.5, 0.042, 1,5, 0.5, 13.0)
84
-------
4 -
H TT-r I r r r i t i~rrr hr n i H'Tr r~(-fr-r -H-r rrrl r i
3.5
(a) Vertical profiles
:!
.1 II !— L._l
.3 - j M i i I IT~I i i I i i i i i I 'i i i i i ' i i i i i I rrr r-rh"rT-r-H-rrn-rl i i r~rH~rrr~rrr
.£75 -~-
•PC
,co
(b) Longitudinal profiles
•2 -t
X
• i -E
.07'J
c n
E/ r
0 1.5
0_L )_L=t-
4.;
1-ftTTE-i.
7.5
x/Hk
i i. Lj.i i 11 i 11
10.5 12
13.5 15
Figure A-34. Case No. 18 concentration measurements.
85
-------
Figure A-34. Case No. 19 smoke visualization (1.5, 0042, 2.2, 1.0, »).
86
-------
Figure A-36. Case No. 20 smoke visualization (1.8, 0.035, 0.7, 1.0, ~)
88
-------
-r-r-rr-|-TT , r-|— rr-\~r +-r-t-r ~rt T i-
(a) Vertical profiles
.£5 .3 .35 .4
45 ,5
. IE
tc5 —
. 1
(•>
-Q075-J-
.05 -
.085 -
rf i i i i i I i i~T~T~r'f'TT~f~i~r~h'rTi~T"r"'r~rr'rTT"fT~r~
—H-r-m-H-T-r-rT-ri-
/
(b) Longitudinal profiles
Q _.U_l_l_ I I I I L. I I I ,..L_I I I I | I i I | I I I
0 1.5 3 4.5 b
.(_J_-i_' i i | i i i i L| i i i i .t | i i i i i
7..S S> 18.5 12 13.5 15
Figure A-37. fase No. 20 concentration measurements.
89
-------
Figure A-38. Case No. 21 smoke visualization (1.8, 0.059, 0.7, 1.0, «),
90
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I t i
(a) Vertical profiles
I I I I I I I I IT1 I i I I I I I I I I I I I I I I I I I
0 .05 .1 .15
.] L_1_J_J__| 1 L
—>-
.£5 .3 .35 .4 .45
. 15
125--
Cf
X
.05 —
i i I i i-! TT+TTTT-H-T T TTTf--rTT~,-r|—m--rj-
(b) Longitudinal profiles li
13.5 ] 5
Figure A-39. Case No 21 oncentt'ation measurements.
-------
Figure A-40. Case No. 22 smoke visualization (1.8, 0.059, 0.7, 0.5, 4.5)
92
-------
3.5 -F
(a) Vertical profiles
. 15
(b) Longitudinal profiles
-» i i i i I i i i i i I i i i i i [ i i 1. 1 ij i i i i i | i i i-rT
.5 9 10.5
0 "M.5 3 4.5
Figure A-41. Case No. 22 concentration measurements.
93
-------
Figure A-42. Case No. 23 smoke visualization (1.8, 0.091, 0.7, 1.0, »).
94
-------
i -i~n—m—h r~H~
(a) Vertical profiles
L. _1_l_4-J_l_L-L_)—l_L_L_l_.|_l_LJ-J .„} -1_L-LJ_J_I_ I i_l_|_J—LJ-.L- -
or
.05 --
.025
M i i ~r~rrrr
TTT rrrr rrr-H TTrr~ln TTI~T'("TT-I TT I rr i r'r'r
(b) Longitudinal profiles j
£ n 1 . 5U
i *"r*jij i
-UULL |_LJ_LL IJ I I I I i I
4.5 t ~ . 5
x/H,
10,5
l_l-4_L_LJ_LJ_)-
13.5 15
Figure A-43. Case No. 23 concentration measurements.
95
-------
Figure A-44. Case No. 24 smoke visualization (1.8, 0.091, 0.7, 0.5, 4.2),
96
-------
3.5 —
T-T i -rT-| --|-;~r-r-r
H-T
(a) Vertical Profile
xUrHb2/Q
-I ' L I J l.i l_| ! J..L J. I.
_ 4 _ .15 _ 'c;
i cr I . . . --t r-.
. 1 o H n FT i TT
. 125
rl TTTTT +~r -rgrr f- r -na~R~T~rT~r
(b) Longitudinal profiles ::
1Q.5 i£ 13.5 15
Figure A-45. Case N). 24 concentration measurements.
97
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Figure A-46. Case No. 25 smoke visualization (1.8, 0.091, 0.4, 1.0, =°)
98
-------
Figure A-47. Case No. 26 smoke visualization (1.8, 0.091, 0.4, 0.5, 4.2)
99
-------
Figure A-48. Case No. 27 smoke visualization (2.15, 0.076, 0.7, 1.0, »)
TOO
-------
Figure A-49. Case No. 28 smoke visualization (2.15, 0.076, 0.7, 0.5, 4.2)
1C2
-------
"I i"rrr + 'r-f-r-rt"r~i—f~t r
'
(a) Vertical profiles
)__L t_L 1_| .l..L_L I-^- I -I L L.j LI _L-L.J_1 JL i.J.|_l I !--!-)- '
.05
.045
.04
.035-^
.03
ri i 1 i •• i~T~H~rTf~r~H~n m"l-r-m-r
"T T Tf TT T" T T~\~m~l ~r\"
(b) Longitudinal profiles
Figure A-50. Case No. 28 concentration measurements.
103
-------
Figure A-51. Case No. 29 smoke visualization (2.5, 0.065, 0.7, 1.0, «)
104
-------
' I" i" i i r t f "• r~r t T~ r TT ~1™ T~I ~r r~l"T 7 i i
(a) Vertical profiles
3.5
2.5--
1.5 --
—!
T
yW/Q
.^ J I_!
.45
.05
.045 +
.84 -;
.035-;
.03 -t
CM
X .02--
.815-;
—TT+T i i i rh
(b) Longitudinal profiles i
LJJ—i.J_LJ-l_
:iru
_1_ULJ
C
I I .1 I f FLl I I |
x/Hb
Figure A-52. Case No. 29 concentration measurements.
105
-------
Figure A-53. Case No. 30 smoke visualization (2.5, 0.065, 0.7, 0.5, 4.2),
106
-------
\-\TI~T: l
r TT -\TI~T: ~n i i ~ri r~i T i r~r rr~r T
(a) Vertical profiles
' LI I | I I I I | L_L_l_L_|_l_L-L_L-).-Ll_i_J_(_L-L_L J _|._L_L_L. L (._ L_L_1. j _|._.L_1- L !.._
0 .85 .1 .15
.c'5 .3 .'55 ,4
cr
CM
.05
.045
.04
.635
.03
* .02--
.0:5
f OE-05--
e
i i I i i i"t~H i i i i i 1 i—rr~T~} i i i ' rl i i rT-~h i : i~i T"r~r~T-r-| -r-i—rr "~
(b) Longitudinal profiles
d
I I I I l I I I l I I I I I I
,D-
l i i l i i .
C
-!_J._1_
-J— L I J I | II I U.L||_LJ_1_L
10.5 12 13.5
15
Figure A-54. Case No. 30 concentration measurements.
107
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TECHNICAL REPORT DATA
(Please read Inunctions on the reverse before completing/
REPORT NO.
EPA-600/4-80-055
3. RECIPIENT'S ACCESSION NO.
4. TITLE ANDSUBTITLE
THE EFFECTS OF A SQUAT BUILDING ON SHORT STACK EFFLUENTS
A Wind Tunnel Study
5. REPORT DATE
December 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR'S)
Alan H. Huber, William H. Snyder
Roger S. Thompson, and Robert E. Lawson, Jr.
B. PERFORMING ORGANIZATION REPORT NO.
Fluid Modeling Report No. 8
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Sciences Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
1AA603
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Sciences Research Laboratory - RTP.NC
Office of Research and Development
U.S. Environmental Protection Agency
Research Trianale Park. NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
In-house
14. SPONSORING AGENCY CODE
EPA/600/09
15. SUPPLEMENTARY NOTES
16. ABSTRACT
In a wind tunnel study, the influence of the highly turbulent region found in the
lee of a model building upon plumes emitted from short stacks was examined through
smoke visualization and tracer gas concentration mappings. The study was conducted in
the Meteorological Wind Tunnel of the EPA Fluid Modeling Facility. A thick, simulated
atmospheric boundary layer was used to provide background dispersion. A rectangular
shaped building with its length equal to twice its height and width was oriented
perpendicular to the approaching wind. In all phases of this study each situation was
repeated with the building removed. This allowed for a simple demonstration of the
building wake effects. A simple mathematical model provided good estimates of concen-
trations in the building wake. The building Influence was found to be reduced with
increases in the effective source height. Application of the "2 1/2 times rule," that
is, an effective source height greater than 21/2 times the height of the building,
avoids significant influence by the building on the maximum ground-level concentration,
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Air pollution
* Wind tunnels
* Chimneys
* Height
* Downwash
* Atmospheric Diffusion
13B
14B
13M
20D
04A
DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
118
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
E»A Form 2220-1 (9-73)
108
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