Study of Vortex Shedding beneath a Free Surface

Abstract

The interaction of the viscous flows with the free surface waves may make the nonlinear fluid motion more complicated. In this paper the vortex shedding from an oscillatory circular cylinder vertically piercing a free surface is investigated by the numerical experiments. The three-dimensional finite volume method using the free surface fitted coordinate system is used for solving the incompressible viscous flow field with a free surface. The numerical results about the viscous flow field around an oscillatory circular cylinder piercing a free surface are shown the effect of the free surface waves on the vortex shedding from the cylinder. The vortex structure shedded from the cylinder is changed in the circular arc-shape in the vicinity of the free surface by the waves. The effect of the free surface waves is discussed by the comparison with the other numerical results about the viscous flow field around a circular cylinder in the oscillatory shear flow field.