Numerical study of wind loads on buildings induced by downbursts: Fid-Bau Portal

Numerical study of wind loads on buildings induced by downbursts

Iida, Yumi / Uematsu, Yasushi

Abstract The wind characteristics of downbursts are quite different from those of turbulent boundary layers. Non-stationarity (e.g., a severe moving downdraft and a strong divergent outflow near the ground) causes severe damage to buildings and structures. In our previous study, the following features of non-stationarity were experimentally reproduced using a downburst simulator: wind speed increase that occurs when the wind hits the ground, wind speed increase resulting from the movement of a downdraft accompanied by that of parent clouds, and wind speed increase caused by a combination of these phenomena. In the experiments, the measurement area of the flow fields and the points of pressure measurements on a building model were so limited that detailed information on the flow and pressure fields could not be obtained. Therefore, in the present, we conduct a computational fluid dynamics (CFD) simulation of downbursts using a large eddy simulation to investigate the mechanism that causes strong winds. We focus on the effects of the aforementioned non-stationarity of downbursts on the wind loads on buildings. The CFD simulation successfully reproduces the experimental results and clarifies the features of downburst-induced wind loads.

Highlights • Effects of movement and impinging jet on the flow field of downburst is investigated. • Non-stationary flow fields of moving and pulsed jet are reproduced in the LES. • Downburst-induced pressure on a building is measured in the LES. • The influence of the static pressure in a downburst is analyzed. • Downburst-induced wind pressure coefficient distribution are different from those by turbulent boundary layers.