Wind flow in an urban environment.

The wind environment at ground leven in built-up areas is influenced by the extremely complex interaction amongst incident wind, mean vertical velocity gradient, turbulence and the shapes, sizes and layouts of building. Random layout of buildings could generate zones of overspeed and vortices in the connecting passage way between buildings, terraces, opensided shelters, courtyards, which could potentially cause unpleasantness, hazard from resuspended particulates, and airborne rain penetration into the buildings. The paper presents the results of two case studies comprising field measurements made within the Kent Ridge Campus, National University of Singapore, using DANTEC 54N10 Multichannel Flow Analyser and Probes. Results are presented in terms of non-dimensional windspeed coefficients. It is concluded that there is significant increase in windspeed due to channel and venturi effects. This information provides useful guidelines for building plans and layouts to the architects and engineers.