The Enhancement of Aerodynamic Characteristics on Bluff Bodies near a Moving Ground

In this study, passive control methods for attaching horizontal and vertical fences on the lower surface of the cylinder near a moving ground were adopted to enhance the aerodynamic characteristics with the changes in gap height. The horizontal fences increase the domain where the lower separated shear layer is interfered by viscous effect on the ground. In a moving ground, this viscous effect is only slightly observed due to elimination of shear layer induced by relative ground motion. However, vertical fences diminish the momentum provision intended to roll up to wake region by blocking the gap flow, thereby suppressing the vortex shedding irrespective of ground conditions. Therefore, the horizontal fences in a moving ground have the advantage of reducing averaged lift and drag though cannot suppress the vortex-induced oscillation. Even though vertical fences have an advantage of suppressing vortex shedding past a cylinder, the existence of the vertical fences themselves causes the averaged drag to increase above the critical gap height due to the existence of vertical fences.