Numerical simulation of thunderstorm downbursts on various urban morphologies

Abstract

Urban structures are vulnerable to the various forces of nature and are regulated by stringent requirements to ensure their ability to withstand adverse weather conditions. One of the most severe weather conditions is the occurrence of thunderstorm downbursts, which are columns of cold air descending very rapidly from a thunderstorm. When the air hits the ground, it radiates outwards, creating strong outflowing winds that can reach high velocities and are potentially damaging to urban structures. This project investigates the drag forces of microburst-like winds on different configurations of building layouts in urban environments. It attempts to identify the factors that affect the resultant drag forces and seeks to provide ways to alleviate the problems caused by these high intensity winds. Two studies were carried out using numerical analysis to examine the effects of various parameters on the resultant drag forces. The first study looked at the frontal and plan area indices, whereas the second study delved into the side street geometry. Both studies were conducted on the OpenFOAM platform using the k-ω SST turbulence model.