STUDY OF WIND FLOW PATTERN AROUND TALL BUILDINGS

Abstract

The high rise buildings are affected by wind load due to wind flow around them. Study of flow around long span suspension bridges, chimney, cooling towers, low and high rise buildings, is of great significance from the structural safety point of view. Prediction of flow characteristics using various turbulence models is very demanding issue. The Flow characteristics play a vital role for stable and safe designing of structures. Different cross sections are used to represent structures like buildings, bridges and other architectural features, so the study of wind flow pattern, induced vortex shedding and various wind load parameters around 2D rectangular cylinder with different aspect ratios(RB/H, is the ratio of breadth of the block to the height in streamwise and cross streamwise direction respectively) have been studied and presented in this paper. Different aspect ratios varying from I to .05 have been used at a fixed Reynolds number 21400(Re = p1J H , where Uis the Free It stream velocity and It is the dynamic viscosity of the fluid) based on free stream velocity and height of the cylinder across the free stream. Although the turbulence is certainly a 3 Dimensional phenomenon, but still an effort has been made to capture the effect of turbulent flow around rectangular bluff body on the time averaged flow quantities using two dimensional turbulence models with suitable assumptions. A comparative study of 2D unsteady RANS equation with standard k- E and RNG k- s turbulence models accompanying near wall treatment has been investigated for wall Y as guidance in selecting appropriate grid configuration using FLUENT 6.3, Results have been compared with the results by Xinhiang Tian et. al.(2012).