Effectiveness of Corner Modification to Optimize Aerodynamic Responses of Square Cylinder

Abstract

This study investigates the effectiveness of a new technique to optimize aerodynamic responses of square cylinder by corner modification. The corner of the square cylinder was modified by introducing a small inclined opening which was measured in terms of corner point dislocation. Four specific opening widths (normalized with the depth of the cylinder) viz. 0.02, 0.08, 0.12 and 0.18 were considered. The normalized length of the inclined opening was 0.05 for all cases. The aerodynamic responses of these four modified square cylinders are compared with the unmodified square cylinder. Direct Numerical simulation was utilized to predict the aerodynamic responses and the flow filed. Second order accuracy was maintained both in space and time. The Reynolds number was kept constant at 100. The mean and RMS values of the force coefficients are calculated and compared. The flow filed is analyzed in terms of vorticity filed, mean flow streamlines and after-body wake characteristics. Due to corner modification, a drag reduction of approximately 5% is achieved for square cylinder with corner opening. Along with the separated flow, the corner opening affected the wake of the cylinder as well. Square cylinder with corner opening had different wake characteristics as compared to the unmodified cylinder.