AN EXPERIMENTAL INVESTIGATION OF WIND LOAD ON TALL BUILDINGS WITH HEXAGONAL CROSS-SECTION

Abstract

An experimental investigation of surface static pressure distributions on hexagonal cylinder was conducted. The study was performed on both the single cylinder and the group consisting of two cylinders, one in the upstream and another in the downstream side. The test was conducted in an open circuit wind tunnel at a Reynolds number of 4.13 x 104 based on the face width of the cylinder across the flow direction in a uniform flow of velocity 13.2 m/s. The study was done on the single cylinder at various angles of attack from 00 to 500 at a step of 100. The surface pressure distributions were measured with the help of an inclined manometer. Then the group of two cylinders was taken into consideration for the study and the surface static pressures were measured for various inter-spacing of 1D, 2D, 3D, 4D, 6D and 8 D, D being the width of the cylinder across the flow direction. In each case the wind velocity was kept constant at 13.2 m/s. The pressure coefficients were calculated from the measured values of the surface static pressure distributions on the cylinder. Then the drag and lift coefficients were obtained from the pressure coefficients by the numerical integration method. It was observed that the drag coefficients become remarkably smaller compared to those for a sharp-edged square cylinder. It was also observed that at various angles of attack, the values of the lift coefficients were insignificant compared to those for a sharp-edged square cylinder. It can be further concluded that the hexagonal cylinder produces significantly low values of drag and lift forces and they approach to those of the cylinder with circular cross-section.