Environmental Engineering Reference
In-Depth Information
−ξ
⎛
⎞
c
r
c
r
0
i
r
2
= (1 +
i
r
2
)
⎜
⎟
−1
(7)
⎝
⎠
where
i
r
0
and
c
r
0
are the plume centerline values and
0 <ξ<1
.
We use a skewed PDF obtained as the sum of two reflected Gaussians for
c
r
(Luhar et al., 2000):
⎛
⎞
(
)
2
(
)
2
−
z
−
z
m
+
2
nz
i
−
z
j
−
−
z
−
z
m
+
2
nz
i
−
z
j
2
∑
N
∑
a
j
2πσ
j
c
r
=
Q
U
⎜
⎜
⎜
⎟
⎟
⎟
2σ
2
2σ
2
e
+
e
(8)
j
=1
n
=−
N
⎝
⎠
where
a
j
,
σ
j
,
z
j
depend on the skewness of the vertical relative coordinate.
5. Results
by the fluctuating plume model compared with the measurements by Coppin et al.
(1986) in a simulated plant canopy.
0.023 m
0.167 m
0.696 m
0.0
0.5
1.0
0.0
0.1
0.2
0.3
0.00
0.02
0.04
0.06
0.08
0.10
0.12
σ
c
/
θ
Fig. 2.
Normalized concentration fluctuations. Black points, Coppin et al. (1986) data. Diamonds,
model results. The number at the top of each plot refers to the distance from the source
