Assessment of Local Pressure Coefficient …
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and transverse vertical structures. This flow structure reveals the streams behind
the unconventional building physics, especially on the sides of the separation and
wake regions. The visualization of vortices indicates the intensity of the turbulence
downstream for the buildings. The upstream horseshoe (HS) vortex in windward face
of the rect building has been compared with the other two buildings. At the same time,
the trailing vortex structure in rect building has an un-symmetrical wake region which
shows the presence of a wake oscillation with lower frequency. This phenomenon
opposes the higher frequency vortex shedding with higher energy turbulence which
is shown in Fig. 4a. In taper building, the area of the wake region reduces along the
height (like a wake funnel as in Fig. 4b). The trailing wake regions in the setback
building differ from the other two buildings as the setbacks on building break the
vortices into small parts which eventually slows down the downstream driving parts.
Moreover, it reduces the vortex stretching downstream, see Fig. 4c. Simultaneously,
the permanently attached upstream edge vortices in windward face and roof of the
setbacks are relatively smaller compared to the rest of the buildings.
3.3 Comparison of Turbulence Intensity Around
the Buildings
Turbulence Intensity (TI) contour for three buildings is presented in Fig. 5. The
TI changes along with the height in the wake zone. In regard to the intensity of
the turbulence on rect building, the maximum intensity is located in the recirculation
region due to viscous shear separated from the leading edge. In taper, the roof leading
edge shear stress influences intensely in downstream wake zone (Fig. 5b), and the TI
core extended up to 5D. The presence of setbacks design on building breaks the core
intensity of the turbulence substantially and dissipates into small eddies downstream
(Fig. 5c).
Fig. 5 Turbulence intensity around buildings a Rectangle, b Taper and c Setback
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and transverse vertical structures. This flow structure reveals the streams behind
the unconventional building physics, especially on the sides of the separation and
wake regions. The visualization of vortices indicates the intensity of the turbulence
downstream for the buildings. The upstream horseshoe (HS) vortex in windward face
of the rect building has been compared with the other two buildings. At the same time,
the trailing vortex structure in rect building has an un-symmetrical wake region which
shows the presence of a wake oscillation with lower frequency. This phenomenon
opposes the higher frequency vortex shedding with higher energy turbulence which
is shown in Fig. 4a. In taper building, the area of the wake region reduces along the
height (like a wake funnel as in Fig. 4b). The trailing wake regions in the setback
building differ from the other two buildings as the setbacks on building break the
vortices into small parts which eventually slows down the downstream driving parts.
Moreover, it reduces the vortex stretching downstream, see Fig. 4c. Simultaneously,
the permanently attached upstream edge vortices in windward face and roof of the
setbacks are relatively smaller compared to the rest of the buildings.
3.3 Comparison of Turbulence Intensity Around
the Buildings
Turbulence Intensity (TI) contour for three buildings is presented in Fig. 5. The
TI changes along with the height in the wake zone. In regard to the intensity of
the turbulence on rect building, the maximum intensity is located in the recirculation
region due to viscous shear separated from the leading edge. In taper, the roof leading
edge shear stress influences intensely in downstream wake zone (Fig. 5b), and the TI
core extended up to 5D. The presence of setbacks design on building breaks the core
intensity of the turbulence substantially and dissipates into small eddies downstream
(Fig. 5c).
Fig. 5 Turbulence intensity around buildings a Rectangle, b Taper and c Setback