Numerical investigation of wind-induced interference in a random urban array

Abstract

The presence of surrounding obstacles influences wind velocity and pressure distributions in a building cluster. Computational fluid dynamics (CFD) modelling approach namely Large Eddy Simulation (LES) was performed in simulating the wind flow in a random urban array comprised of vertically random building clusters. Wind pressure distribution was analysed using two parameters: (a) reference pressure coefficient (Cpref) based on the pressure difference between an arbitrary and free-stream points and (b) wind pressure coefficient ΔCp based on the pressure difference between windward and leeward building surfaces. The contour plots of Cpref surrounding the tallest building showed the wind-induced interference decreased with height for two wind directions tested (0° and 180°), indicated by the increasing Cpref values. The Cpref distribution along the horizontal sections of the same building also showed its values increased with height. Finally, the local interference effects were parameterized in each building cluster containing a target building for which the target ΔCp (henceforth ΔCptarget) and height (htarget) were determined. Current results showed that ΔCptarget / ΔCpave is almost linearly proportional with htarget/have. These findings can be used to assess the wind-induced interference effects on natural ventilation potential particularly in random arrays.