<p>Most simple urban canopy models have focused on the vertical wind profile through obstacles at a constant horizontal drag force and local shear stresses. However, decrease in wind velocity along stream-wise direction because of the mutual sheltering effect of the obstacles has not been appropriately addressed. In the simple urban canopy model originally developed by Cionco and modified by Sabatino, 10%–25% over- and underestimation of wind speed was observed at the ground level in the Stream-wise direction. Furthermore, the effects of the wind incident direction and passage angle on flow losses were not considered in previous models. In this paper, the Sabatino model is further modified for analyzing pedestrian-level wind flow through urban canopies and passages. In the modified model, flow losses in the stream-wise direction because of the mutual sheltering effects and various urban canopy parameters were accounted for by multiplying the horizontal drag factor, a factor based on the hybrid multiple linear regression analysis of the experimental data. In addition, flow losses owing to the stream-wise distance through the urban canopy, wind incident angle, and passage angle were considered. The results were compared with wind tunnel experiment results of a regular array of cross-shaped elements. All residuals were within ± 0.2. Moreover, the correlation among wind incident angle, passage angle, and wind flow through the passages is discussed in detail.</p>

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Pedestrian level wind flow analysis: a mathematical and statistical-oriented approach

  • M. Zahid Iqbal Qureshi,
  • Abdul Waheed Badar

摘要

Most simple urban canopy models have focused on the vertical wind profile through obstacles at a constant horizontal drag force and local shear stresses. However, decrease in wind velocity along stream-wise direction because of the mutual sheltering effect of the obstacles has not been appropriately addressed. In the simple urban canopy model originally developed by Cionco and modified by Sabatino, 10%–25% over- and underestimation of wind speed was observed at the ground level in the Stream-wise direction. Furthermore, the effects of the wind incident direction and passage angle on flow losses were not considered in previous models. In this paper, the Sabatino model is further modified for analyzing pedestrian-level wind flow through urban canopies and passages. In the modified model, flow losses in the stream-wise direction because of the mutual sheltering effects and various urban canopy parameters were accounted for by multiplying the horizontal drag factor, a factor based on the hybrid multiple linear regression analysis of the experimental data. In addition, flow losses owing to the stream-wise distance through the urban canopy, wind incident angle, and passage angle were considered. The results were compared with wind tunnel experiment results of a regular array of cross-shaped elements. All residuals were within ± 0.2. Moreover, the correlation among wind incident angle, passage angle, and wind flow through the passages is discussed in detail.