An Experimental Study on Aerodynamic Drag of Rectangular Cylinders

Abstract

An experimental study is carried out on the aerodynamic drag of rectangular cylinders, where the REYNOLDS number ranges up to 6×10⁴. It is revealed that the drag coefficient, CD, varies con-siderably with the d/h ratio of rectangles, and that the maximum value of CD is as high as 2.6 for d/h of 2/3 compared with CD of about 2.0 for the cases of flat plate and square cylinder (Fig.1). The STROUHAL number of the shedding vortices, on the contrary, remains approximately constant for d/h up to 1.0, decreases slowly for larger values of d/h, and then increases abruptly at d/h ratio of about 2.8 (Fig.2), where the flow reattaches on the lateral surfaces of the cylinder.