论文标题
直接模拟带有粒子间内聚会的空气动力学夹带
Direct simulation of aerodynamic entrainment with inter-particle cohesions
论文作者
论文摘要
空气动力学的夹带是盐酸运动的先驱，对于理解风险现象的发展至关重要。在这里，我们对使用离散元素方法在随机布置的沉积床上表面颗粒的空气动力学提升进行了直接的数值模拟，并提供了证据，证明颗粒不会垂直离开床，而速度等于达到一个晶粒直径所需的速度，因为人们广泛接受，但朝着床表面较小的角度和较大的Velocities。夹带速率不会与剪切速度表现出二次依赖性，而是几乎线性的，因为被夹带的粒子的速度随剪切速度线性增加。此外，颗粒间内聚力会显着增加流体夹带阈值，但对夹带率以及夹带颗粒的起飞速度和角度分布没有影响，因为夹带和床颗粒之间的碰撞破坏了粒子间键。给出了完全夹带的计划，该计划提供了一种可靠的方法来探索风险运输的发展和演变。
Aerodynamic entrainment acts as the pioneer of saltation movement and is critical for understanding the development of aeolian phenomena. Here we performed direct numerical simulations on the aerodynamic lifting of surface particles on a random arranged sediment bed using the discrete element method, and provided evidence that particles do not leave the bed vertically with speeds equal to that needed to reach a height of one grain diameter, as people widely accepted, but with much smaller angles toward the bed surface and much larger velocities. The entrainment rate does not exhibit a quadratic dependence with the shear velocity, but a nearly linear one, because the velocity of entrained particle increases linearly with shear velocity. Moreover, inter-particle cohesion increases the fluid entrainment threshold significantly, but has no effect on the entrainment rate, as well as the take-off velocity and angle distributions of entrained particles, because the collisions between entrained and bed particles destroy the inter-particle bonds. The completely entrainment scheme is given, which provides a credible approach to explore the development and evolution of aeolian transports.
