G0500704 The aerodynamic characteristics of square cylinder with the concave shape of two dimensional flow

Abstract

In recent years, there are many researches about aerodynamic characteristics on the various cross sectional shape of the bluff body. For example, the shapes of edges of square cylinder are splay, roundish and cutout edges. It is known that the drag force of these cylinders reduce compared with the normal square cylinder. The purpose of this research is to clarify the aerodynamic characteristics of the square cylinder with the concave shape. The drag is measured by using wind tunnel experiment. The concave shapes are made by acrylic plates which are affixed on the both sides of the square cylinder. The acrylic plate has 3mm thickness. The lengths of the concave are 3, 6, 9mm respectively. The concave is attached in the front or rear of the square cylinder. As a result, the drag coefficient decreases as the length of the concave increases. The drag reduction of the square cylinder with the front concave is lower than that with the rear concave. The square cylinder with the length of 9mm and the rear concave has the highest reduction rate of drag coefficient with 13.1%.