论文标题
重力沉降对小惯性颗粒与球体的碰撞的影响
Effect of gravitational settling on the collisions of small inertial particles with a sphere
论文作者
论文摘要
当形成者在重力的效果下也沉降时，发现小惯性颗粒与中等雷诺的球形体相撞的速率受到强烈影响。小颗粒的沉积确实改变了发生碰撞的临界数字。这是由由于小颗粒感知的有效速度场的停滞点的不稳定歧管引起的屏蔽效应所解释的。还发现存在一个次要的临界stokes数字，没有发生碰撞。这是由于大螺旋数颗粒颗粒更快地沉降的事实，这使得更大的人更难赶上它们。尽管如此，在这种状态下，流动干扰在收集器之后会产生复杂的粒子分布，有时允许背部碰撞。这可能会导致在弗鲁德数字的大值下，碰撞效率高于统一的碰撞效率。
The rate at which small inertial particles collide with a moderate-Reynolds-number spherical body is found to be strongly affected when the formers are also settling under the effect of gravity. The sedimentation of small particles indeed changes the critical Stokes number above which collisions occur. This is explained by the presence of a shielding effect caused by the unstable manifolds of a stagnation-saddle point of an effective velocity field perceived by the small particles. It is also found that there exists a secondary critical Stokes number above which no collisions occur. This is due to the fact that large-Stokes number particles settle faster, making it more difficult for the larger one to catch them up. Still, in this regime, the flow disturbances create a complicated particle distribution in the wake of the collector, sometimes allowing for collisions from the back. This can lead to collision efficiencies higher than unity at large values of the Froude number.
