Effects of corner chamfers on the extreme pressures on a square cylinder at incidence to a uniform flow

Abstract

Wind-induced damages to cladding, glass curtain walls, and windows on surfaces of buildings demand further investigation of extreme pressures on a square prism. The flow physics of extreme wind pressures on a square cylinder has not yet been clarified, especially as they relate to corner modifications and flow incidence. Large-eddy simulation is utilized to investigate uniform flow past a standard square cylinder and a chamfered cylinder with a chamfer ratio of 1/7. The Reynolds number is fixed at 22,000, and the incidence angle ranges from 0° to 45°. The flow mechanism of extreme pressures is studied through analyses of instantaneous flow structures. The influences of corner modifications on extreme pressures are further investigated. The results show that extreme negative pressures are strong in the non-Gaussian regions, which are observed at the rear corners and sides of the two cylinders and change dramatically as the incidence changes. Two types of flow structures are responsible for the extreme pressures, namely, the intermittent rear-corner vortices caused by reverse-flow separation and the Karman vortices near the rear side. The distribution of extreme pressures is highly three-dimensional, owing to 3D vortex structures at a high Reynolds number. By introducing chamfers, the strength and spanwise variations in the corner vortex are reduced, and extreme pressures are weakened.