Chapter 4
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Table 4.1. Details of involved urban morphology parameters for CFD simulation cases. Case name
Street
H/W
Urban area
Frontal
Urban
Corner
Wind
area
layout
shape
direction
0°
canyon
plan
width,
density
density
W/B A1
0.15
30
0.76
3.40
In-line
A2
0.3
15
0.59
2.66
In-line
Sharp Sharp
In-line
Sharp
0°
In-line
Sharp
0°
In-line
Sharp
0°
In-line
Sharp
0°
In-line
Rounded
0°
In-line
Rounded
0°
In-line
Rounded
0°
In-line
Rounded
0°
In-line
Rounded
0° 0°
A3 A4 A5 A6 B1 B2 B3 B4 B5
0.45 0.75 1 2.25 0.15 0.3 0.45 0.75 1
10 6 4.5 2 30 15 10 6 4.5
0.48 0.33 0.25 0.09 0.76 0.59 0.48 0.33 0.25
2.14 1.47 1.13 0.43 3.40 2.66 2.14 1.47 1.13
0°
B6
2.25
2
0.09
0.43
In-line
Rounded
C1
0.5
9
0.4
2
Staggered
0°
C2
1
4.5
0.25
1.13
Staggered
Sharp Sharp
0°
0°
C3
0.5
9
0.4
2
Staggered
Rounded
C4
1
4.5
0.25
1.13
Staggered
Rounded
0°
D1
0.15
30
0.76
3.40
In-line
D2
0.3
15
0.59
2.66
In-line
Sharp Sharp
45° 45°
D3
0.45
10
0.48
2.14
In-line
Sharp
45°
In-line
Sharp
45°
In-line
Sharp
45°
In-line
Sharp
45°
In-line
Rounded
45°
In-line
Rounded
45°
In-line
Rounded
45°
In-line
Rounded
45°
In-line
Rounded
45°
In-line
Rounded
45°
D4 D5 D6 D7 D8 D9 D10 D11 D12
4.3.2
0.75 1 2.25 0.15 0.3 0.45 0.75 1 2.25
6 4.5 2 30 15 10 6 4.5 2
0.33 0.25 0.09 0.76 0.59 0.48 0.33 0.25 0.09
1.47 1.13 0.43 3.40 2.66 2.14 1.47 1.13 0.43
Computational domain and grid
The extent of the computational domain from the building array border to the top, lateral, inlet, and outlet boundaries of the computational domain covers 4H, 4H, 4H, and 15H, respectively, following the requirements of the CFD best-practice guidelines [86, 99]. The details of the high-resolution and high-quality computational mesh for Case A4 are depicted in Fig.4.6, with the magnification of grids near the roof and ground. The minimum cell volume in canyons is 5.5×10-3 m3 in the streamwise, lateral and vertical directions. The grid size is enlarged from the border of high-rise building arrays to the boundaries of the computational domain with an expansion ratio below 1.1. This study arranges the distances from the center points of near-wall cells to the building and ground surfaces below 0.3 m (i.e., the y+ values ranging from 30 and 500) to ensure effective implementation of the standard wall functions in CFD computations. The total
