Numerical Study of the Flow and the Sand Movement around a Circular Cylinder Standing on the Sand

The flow around a circular cylinder standing on the sand is computed numerically and the movement of the sand is investigated. The numerical method employed in this study can be divided into three parts : (1) calculation of the air flow around the cylinder using MAC method with a generalized coordinate system ; (2) estimation of the sand transfer caused by the flow through the friction ; (3) determination of the shape of the ground. Since the computational area changes at step (3), this procedure has to be repeated at each time step. Results show that the horseshoe vortex scoops out the ground in front of the cylinder and the wake makes the sand accumulate in the rear region. The dented region becomes deeper as the cylinder leans windward.