Effects of spanwise geometric disturbances on a bluff body wake

Abstract

Previous studies have shown that spanwise, geometric variations in the trailing edge of a base flow can give rise to significant base pressure reduction. In this study, wind tunnel experiments are conducted on a bluff model modified to include both straight-edged and wavy geometric disturbances, whilst essentially retaining the shape of the base. The results show that the base pressure recovery can be as high as 23% for a straight-edged disturbance and 27% for an in-pbase asymmetric disturbance. From a base drag reduction optimization objective, an in-phase wavy disturbance is found to perform better than a straight-edged profile. Finally, the observed base pressure recovery Is consistently accompanied by an attendant increase in the dominant shedding frequency.