Reynolds Number Effects on Aerodynamic Force Coefficients of 2D Rectangular Prisms

Abstract:

Experiments on 2D rectangular prisms with side ratios of 2.0, 2.5, 3.0, 3.5 and 4.0 are reported in this study. The tests were conducted in TJ 2 wind tunnel to measure the wind pressures on the surfaces of 5 models for the testing Reynolds numbers ranging from 1.1×105 to 6.8×105. Aerodynamic forces were obtained by integrating the wind pressures around the model surface. The Reynolds number effects on the aerodynamic force coefficients and the power spectrums of aerodynamic force coefficients are presented, and the influence of side ratio on the drag force coefficients is analyzed. The results show that the aerodynamic characteristics of rectangular prisms with side ratio between 2 and 4 are Reynolds number dependent, and the rectangular prisms appear to be more sensitive to the Reynolds number with increasing side ratio. The along fluctuating wind force is produced mostly by the along fluctuating wind speed, and the vortex shedding plays a second role, whereas the crosswind lift force is mainly from the vortex shedding.