Wind Energy

x1/B
0.3 0.5 0.8 1.0
9 Pollutant Dispersion in Flow Around Bluff-Bodies Arrangement 51
a
0.5 1.5 2.5 3.0
−1.5 −1.0 −0.5 0.0 0.5 1.0 1.5 −1.5 −1.0 −0.5 0.0 0.5 1.0 1.5 −1.5 −1.0 −0.5 0.0 0.5 1.0 1.5
x2/B x2 /B
x2/B
Fig. 9.2. Isolines of mean concentration in the inter-obstacle gap a) S/B = 2,
b) S/B =4,c)S/B =6
C k[%]
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
−2 −1
0
x 2/B
b
1.0 2.0 3.0 4.0 5.0
1
s/B = 6
s/B = 4
s/B = 2
x1/B = 1
Fig. 9.3. Mean concentration profiles for various inter-obstacle gap width
case concentration peaks are distinctly moving towards the flow axis and for
the distances x1/B > 0.75 maximum values of mean concentration are in the
centreline of the wake. The region of higher CO2 concentration is noticeable
in the whole inter-obstacle gap.
Mean concentration profiles for various inter-obstacle gaps and for the
same position of x1/B = 1 behind the upstream cylinder are presented in the
Fig. 9.3. As one can notice, in the case of S/B =2andS/B = 6 maximum
values of mean concentration are outside of the gap region, while for the gap
width S/B = 4 maximum value of mean concentration is in the centreline
of the wake. Computational profiles of the mean velocity components and
numerical distribution of turbulence energy for the same cross section (x1/B =
1) were used to find explanation. It was revealed that velocity distributions
are similar so the question arises why the concentration profiles are different.
To find an explanation the results of computational modelling of velocity
field performed by Gnatowska & Jar˙za [1] have been used. The numerical
2
c
2.60
2.49
2.38
2.27
2.16
2.05
1.94
1.83
1.72
1.61
1.50