Numerical study of the sand movement around a cylindrical body standing onthe sand

The flow around a cylindrical body standing on the sand is computed numeric ally and the movement of the sand is investigated. The numerical method emp loyed in this study can be divided into three parts: (1) calculation of the flow around the pole using the marker and cell (MAC) method with a general ized coordinate system; (2) estimation of the sand transfer caused by the f low through friction; (3) determination of the shape of the ground. Since t he computational area changes at step (3), this procedure has to be repeate d at each time step. Results show that the-horseshoe vortex scoops out the ground in front of the pole. When the pole stands vertically on a flow, it generates a big horseshoe vortex to make the scouring force strong. On the other hand, when the pole has a cross section that is flatter along the flo w, such as a lens or ellipse, the scouring force becomes weaker. Furthermor e, it is found that the horseshoe vortex becomes smaller when the pole has a conical base.