Wind tunnel measurements of the aerodynamic characteristics of a 3:2 rectangular cylinder including non-Gaussian and non-stationary features

Abstract

This paper presents a wind tunnel investigation of the aerodynamic characteristics (force and pressure coefficients) of a static 3:2 rectangular cylinder in smooth flow for angles of attack between −4° and 90° at various values of Reynolds number. In contrast to much of the existing literature, this study shows clear dependence of the mean drag coefficients on Reynolds number. In addition, the variation of aerodynamic parameters with angle of attack is fully mapped for a symmetric section revealing that the peak values of the mean values of drag, lift, moment and Strouhal number do not occur at the same critical angle of attack.The present study also presents the first map for identifying the locations of the reattachment and stagnation points as well as the zones of angle of attack where the flow is separated and attached on a face of the section. The phenomenon of switching flow is observed at the angle of attack 25°, leading to strong non-stationarity and non-Gaussian distributions of the aerodynamic forces and pressure. Another phenomenon, so-called unsteady low-frequency vortex shedding, is also observed at higher angles of attack. These phenomena need to be accounted for when estimating wind loading and aeroelastic instability for these sections.