Numerical Study of the Effect of Flow Fields on the Shape of Sand Dune

概要

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Three-dimensional flow above the sand dunes have been studied numerically by using Large-Eddy Simulation (LES) method. In the flow direction and span direction cyclic boundary conditions are imposed for velocity and pressure. The movement of the sand which is known as the two kinds of the elemental types of desert have been investigated. The numerical method employed in this study can be divided into three parts: (i) calculation of the air flow above the sand dunes using standard MAC method with a generalized coordinate system; (ii) estimation of the sand transfer caused by the flow through the friction; (iii) determination of the shape of the ground. Since the computational area has been changed due to step (iii), steps (i)-(iii) are repeated until prescribed times. One kind of the simulated dunes, which is formed by unidirectional wind, develops wings from the each end of them, connects with each other and becomes essentially parallel straight ridges which is known as transverse dune. The other one, which is formed by two directional winds, extends at the converging direction which is known as linear dunes.
日本学術会議「機械工学委員会・土木工学・建築学委員会合同IUTAM分科会」の論文