Urban wind flows: wind tunnel and numerical simulations—a preliminary comparison

Previous studies have indicated that wind flow models based on the k− formulation are able to simulate the broad features of flows as observed in field programs and wind tunnel studies. k− models are increasingly being used to investigate the dispersion of pollutants and the transfer of heat within and out of urban canyons. In these situations realistic modelling requires greater fidelity on the part of the wind flow specification in that some confidence needs to be placed on the actual magnitude of the wind speeds and turbulent viscosities used in the dispersive components of the models. To this end a preliminary comparison of wind tunnel and numerical modelling was undertaken. It has demonstrated general agreement between the two types of modelling but has also indicated some differences. These are in the variation of concentration with height at the windward wall and in the concentration gradients away from the canyon boundaries.