Along and across wind effects on irregular plan shaped tall building

Abstract

This paper presents detailed study of force and pressure coefficients of an unsymmetrical ’E’ plan shaped tall building under wind excitation. The building is unsymmetrical about both direction (along and across wind direction) in plan. Experimental and numerical study is carried out by wind tunnel test in boundary layer wind tunnel and Computational Fluid Dynamics (CFD) technique using ANSYS CFX software respectively to study the above model under wind excitation. Two different types of models were used for force and pressure measurements in wind tunnel. Rigid model was used at a model scale of 1:300 for both the cases. Force measurement model was tested under three different wind speeds of 6, 8, 10 m/s whether pressure measurement model was tested under wind speed of 10 m/s in wind tunnel. Wind flow pattern around the building model is studied by CFD technique for both wind flow direction which predicts about the nature of pressure distribution on different surfaces. Some dynamic nature of wind flow is observed at the rear side in case of across wind effects. Maximum positive force and pressure coefficients noticed in case of along wind effects as the surface area is maximum and maximum wind energy dissipates on frontal surface. Same mean pressure occurred on similar faces in case of along wind effects. Pressure contours are symmetrical about vertical axis on frontal faces for both directions of flow and pressure fluctuation noticed at the rear side face due to dynamic effects of flow pattern in case of across wind effect. A comparative study is carried out between experimental and numerical study and results found from these two methods have good agreement to each other.