Experimental Study of Passive Jet Flow Control of Chamfered Square Cylinder

Abstract

This study conducted wind tunnel tests to verify a passive jet flow control method for suppressing the aerodynamic force on a chamfered square cylinder at a moderate Reynolds number, focusing on the influence of the opening parameters and the spanwise spacing ratio of hollow pipes on the jet flow control effect. The pressure coefficient distribution on the surface of the cylinder and the overall aerodynamic coefficient were considered in order to systematically analyze the influence of opening shape, opening number, opening height, pipe height, and pipe radial thickness, and to determine the optimal combination of opening parameters. Subsequently, we analyzed the influence of the spanwise spacing ratio on passive jet flow control. Furthermore, the optimal arrangement of the hollow pipe was derived by comparing the aerodynamic coefficients of uncontrolled and controlled cylinders. The results revealed that the passive jet hollow pipe significantly reduces the root mean-square value of the pressure coefficient and the fluctuation of the lift coefficient. Moreover, the platform area of the mean pressure coefficient at the leeward side of the cylinder increases and the mean drag coefficient decreases. The spectrum analysis results showed that the passive jet flow control pipe alters the frequency and intensity of vortex shedding in the wake region. All results indicated that the aerodynamic forces and wakes of a chamfered square cylinder are effectively controlled through jet flow control with perforated hollow pipes.