Wake and Drag Reduction of Bluff Bodies

Abstract

This paper describes an experimental study on the near wake behind bluff body in relation to the base drag reduction. The experiments were carried out using the models with two-dimensional blunt trailing edge and with periodically three-dimensional one. REYNOLDS number based on uniform velocity and base thickness is lessthan 8×10₃.
Behind the two-dimensional bluff body, the periodic vortex shedding occurs and the static pressure reduces in the vortex formation region. In the case of the three-dimensional model, it is observed as a general tendency that the static pressure reduction and the concentration of periodic vortices are not notable. This seems to be the essential feature associated with the drag reduction of three-dimensional bluff body.