风沙流中颗粒剪应力分析

Analysis of Particle Shear Stress in Windblown Sand Movement

分析了两种颗粒剪应力的定义,一种来自于颗粒黏性阻力,一种来自于颗粒相雷诺应力。通过建立三维风沙流离散颗粒模型,计算分析了这两种颗粒剪应力的差别。结果表明,除了近地面附近,这两种颗粒剪应力基本相等。而在近地面附近,来自于颗粒相雷诺应力的颗粒剪应力小于来自于颗粒黏性阻力的颗粒剪应力,这种差别的主要原因是由于在近地表而附近,颗粒碰撞会产生附加碰撞剪应力。

Two kinds of particle shear stress are analyzed, one is from drag force, the other is from dispersed phase Reynolds stress. The three-dimensional discrete particle model is developed for windblown sand movement to reveal the difference between the two kinds of particle shear stress. The results show that except the region near the sand bed surface, the two kinds of particle shear stress are almost same. While near the sand bed surface, the particle shear stress from dispersed phase Reynolds stress is less than that from drag force. The main reason is that near the sand bed surface, the additional collision shear stress will be produced due to particle collisions.