Unsteady aerodynamics of stationary elliptic cylinders in subcritical flow

Abstract

The aerodynamics of a set of two-dimensional elliptic cylinders with eccentricity of 0.8 and 0.6 is studied experimentally during the organized wake condition. The dynamic calibration of the transducer used for measurement of fluctuating pressures is described in detail. The data on Strouhal number, unsteady pressures and wake geometry are presented as a function of angle of attack during static condition of the models. The effect of Reynolds number on the fluctuating pressure is also examined. The results indicate dependence of the unsteady forces on Reynolds number at zero angle of attack. Basing the Strouhal number on projected width appears to reduce its dependence on the angle of attack of the models. The existence of a large phase angle between the fluctuating pressures is of interest. The wake geometry study indicates a gradual reduction in the ratio of the lateral to the longitudinal spacing with increase in angle of attack.