Pedestrian-level wind conditions around buildings for wind comfort assessment

Abstract

The practice of investigating the pedestrian level wind environment, so called wind engineering, is now ubiquitous. Many city case studies exist in literature but few systematic studies of common urban architectural features exist. Among these common features is the simple channel which is common in large cities and has been well documented in literature as leading to significant wind speed increases. This study investigates the effects of adding a blockage at the channel inlet on observed velocities in the channel centerline on 1:100 scale with a view to applying the results to full scale. Time averaged velocity profiles were used to investigate the effect of blockage size and channel width on wind speed amplification. It was found that counter-intuitively, the size of the blockage at the inlet is not proportional to the size of the peak velocity reduction in the channel. The largest blockage created a minimum flow speed reduction (K = 0.98) for a channel width of 200mm. It was outperformed by the smallest blockage for a channel width of 300mm where a greater speed reduction was observed (K = 1.04). It was found that for buildings nearing the interaction flow regime the addition of a blockage has negligible effect on speed.