Effect of suction control on the aerodynamic characteristics of an elliptical cylinder

Abstract

To investigate the effect of suction control on the aerodynamic characteristics of an elliptical cylinder immersed in uniform flow, wind tunnel tests of four elliptical cylinder models E1~E4 with different locations of suction holes were carried out under different suction flux coefficient CQ. The Re number based on the equivalent diameter of each model and the oncoming wind speed is about 6.90 ​× ​104. The results show that CQ, the radial angles of suction holes and the placement of main axis of the elliptical model are the main influence factors for the aerodynamic characteristics, which are mainly reflected in terms of the pressure coefficient distributions and aerodynamic force coefficients. There is a threshold value of CQ for the models under suction control, and a significant change of the aerodynamic characteristics occurs when CQ is within it, while the change turns to be unobvious with the further increase of CQ. And the threshold values of CQ are determined to be 0.01, 0.02 and 0.01 for the models E1, E2 and E4 respectively. Among the cases that the major axis of elliptical cylinder is parallel to the oncoming wind direction, the most effective aerodynamic control is acquired by the model E2 whose suction holes are arranged at the leeward side corresponding to the radial angles of 130° and 230°, and the maximum reduction of CD is about 83.7% at CQ ​= ​0.05 when compared to the case without suction control. The aerodynamic characteristics are also significantly improved by suction control for the case that the major axis of elliptical cylinder is perpendicular to the oncoming wind direction, and the maximum reductions of CD, CσD and CσL are about 62.2%, 75.1% and 87.4% respectively.