INVESTIGATION OF VORTEX SHEDDING FROM CYLINDERS IN SHEAR FLOW

This paper examines the effects the presence of an upstream shear profile has on vortex shedding from short cylinders (L/D equals 6) and relatively long cylinders (L/D equals 24). The investigation was carried out experimentally in a low speed wind tunnel. The steepness parameter of the shear beta was 0. 068 for the short cylinder and 0. 016 for the long cylinder. Measurements covered the mean velocity field, fluctuating velocity components and the fluctuating surface pressure. The results indicate that vortices are shed in cells along the span of the long cylinder in shear flow with the shedding frequency being constant in each cell but different for different cells, with the shedding strength attaining its peak near the ends of the cylinder. On the other hand, the presence of upstream shear tends to prevent any organized shedding from short cylinders.King Saud Universit