Numerical study of unsteady flows past a rotating wavy cylinder

In the present paper, three-dimensional unsteady flows past a rotating wavy cylinder have been studied through numerical simulations. The behavior of the lift forces acting on a rotating wavy cylinder and a rotating straight cylinder is compared, respectively. The results suggest that the rotation rate of the wavy cylinder has to be about two times that of a straight rotating cylinder in order to obtain the same value of the mean lift. The pressure distribution and the vortex structures in the wake of the rotating wavy cylinder at various rotation rates are also demonstrated and analyzed in this work. As rotation rate of the cylinder increases, the vortex formation length increases and the periodic shedding of the Karman vortex is suppressed. Three-dimensional vortex structures in the wavy cylinder wake are visualized at various rotation rates. Due to the surface rotation effect, a distinct difference exists in the vortex structures between a rotating wavy cylinder and a stationary wavy cylinder.