风沙流中沙粒拖曳力系数研究

A Study on the Drag Coefficient of Sand Particles in Wind Sand Flux

拖曳力系数是计算风沙流中沙粒受空气阻力的重要参数。考虑实际风沙流中沙粒浓度及沙粒形状,利用FLUENT软件首先计算了不同风速下距地表不同高度处两沙粒的拖曳力系数,给出了影响沙粒拖曳力系数的间距范围,然后计算了真实风沙流中不同高度沙粒拖曳力系数。结果表明,给定风速下拖曳力系数随距地面高度的增加先减小后增加,并将沙粒拖曳力系数拟合成距床面高度的函数,该函数与风速有关。

Drag coefficient is an important parameter for calculating the air resistance acting on sand parti- cles in the wind sand flux. In this paper, taking sand concentration and sand shape in the actual situation in- to account, the drag coefficients of two sand particles that are at different heights from the surface are calcu- lated using FLUENT software. Influence of wind velocity and interval between sand particles on the drag co- efficient is discussed. Then the drag coefficients at different heights have been calculated in actual wind sand flux. The result indicates that at a certain wind velocity, with the increase of height from the surface, the drag coefficient first decreases and then increases. Lastly, a formula of drag coefficient is fitted, which is a function of height and relates to wind velocity.