沙粒跃移云及Magnus力对床面有效粗糙度的影响

建立了考虑Magnus效应的、吹过平坦沙面的稳定风场中风与跃移沙粒相互耦合的风沙跃移云模型,并通过数值模拟研究了风沙跃移运动对床面粗糙度的影响。结果表明,跃移沙粒对风速的影响类似于床面粗糙度的影响,有效粗糙度随摩阻速度的变化关系可用二次函数表征;Magnus力对有效粗糙度有明显的影响,但这种影响并不改变有效粗糙度与摩阻风速之间的二次函数关系。

Effects of Wind-blown Sand Movement and Magnus Force on Effective Roughness

In this paper, coupled equations between wind and saltating particles are presented for a stable wind blowing over an infinite plane bed and the equations are solved for examining the effects of moving sand and Magnus force on the effective roughness. The calculated results show that the effect of the moving sand in the fluid outside the region to which saltation is confined, is similar to that of solid roughness, and the effective roughness can be depicted as the quadratic function of the friction velocity of the wind. Magnus force has notable effects on the effective roughness, but it does not change the quadratic function relation between the effective roughness and the friction velocity of the wind.