风沙跃移中颗粒与多粒径床面碰撞的数值模拟

采用考虑颗粒碰撞的欧拉-拉格朗日数值模拟方法,对风沙跃移中颗粒冲击多粒径床面的碰撞过程进行了数值计算。在模型中,对气相采用欧拉方法建立控制方程,对离散颗粒采用拉格朗日方法模拟,颗粒间碰撞作用采用软球模型描述。计算结果表明该模型可以模拟风沙运动中颗粒冲击多粒径床面的动态运动过程。而且在多粒径非均匀床面上的颗粒起跳具有较大的随机性。这有助于进一步揭示风沙运动中颗粒碰撞起跳机理。

NUMERICAL SIMULATION OF PARTICLES IMPACTING MULTIPLE-GRAIN SIZE BED IN SALTATION

Numerical simulation of particles impacting multiple-grain size bed is performed with Eulerian-Lagrangian model. In the model, governing equations of gas are established with Eulerian approach, and particle phase is simulated by Lagrangian approach. The soft sphere model is used to describe inter-particle collisions. The results show that the model can really simulate the dynamic process of particle-bed interaction in saltation, the particle ejection velocity and angle are very stochastic on multiple-grain size bed. So the simulation is helpful to reveal the particle impact initiation mechanism in aeolian sand movement.