Numerical Investigation of the Wind Action Over Lowrise Buildings Using Large Eddy Simulation and a Sinthesized Turbulence Generator

Abstract

A numerical model using Computational Wind Engineering (CWE) techniques is employed in this work to investigate the wind action over low-rise buildings. The increase observed in the global temperature of the earth during the last decades, which is mainly originated by climatic changes induced by the greenhouse effect, has lead to the development of cyclones and tornadoes over areas located in the southern region of Brazil. These climatic phenomena have produced important damages to low-rise buildings like houses, warehouses, silos and gymnasiums. In conjunction with experimental tests employing wind tunnels and recommendations proposed by the Brazilian standard (NBR-6123: Forças Devidas ao Vento em Edificações), numerical simulation has been considered lately as an important alternative to evaluate the wind action on buildings and to predict possible failures. A numerical model based on the Finite Element Method is adopted here to simulate the action of wind flows over low-rise civil structures, where the influence of turbulent fluctuations on the incident stream is also considered by using a numerical method to generate synthesized fluctuations over the inlet boundary conditions. Important information such as aerodynamic coefficients and flow fields around the buildings are obtained. Examples related to buildings usually subjected to structural damages during the incidence of strong winds are analyzed and results are compared with experimental predictions obtained from wind tunnel tests.