Abstract

We use numerical simulation to investigate the effect an intruder’s shape has on the drag and lift forces that it experiences while moving through a granular medium composed of polydisperse disks of mean diameter d. The intruder velocity, v, was varied from 0.1 $\sqrt{dg}$ to 20 $\sqrt{dg}.$ For frictionless particles ($\mu =0.0$), there is a gradual increase in drag force with increasing v, whereas, for frictional systems ($\mu =0.1,0.5$), a constant drag regime appears at low velocities. The drag force depends weakly on the object’s shape provided that its cross-section is constant. The drag force depends linearly on the immersion depth, while the lift force varies weakly with depth for certain shapes. The lift experienced by the object is a strong function of its shape at a given velocity. The shape has an effect on the distribution of contacts around the surface of the intruder, which may result in a strong lift for certain shapes. We also present and discuss the force profiles around the intruder surface.

摘要

我们使用数值模拟来研究入侵者的形状对其在穿过由平均直径为d的多分散盘组成的粒状介质时所经历的阻力和升力的影响。入侵者速度v从 0.1 变化$\sqrt{dG}$到 20$\sqrt{dG}.$对于无摩擦颗粒（$\mu =0.0$)，随着v的增加，阻力逐渐增加，而对于摩擦系统 ($\mu =0.1,0.5$)，在低速时出现恒定阻力状态。如果物体的横截面是恒定的，则阻力微弱地取决于物体的形状。阻力与浸入深度呈线性关系，而对于某些形状，升力随深度的变化很小。物体所经历的升力是其形状在给定速度下的强函数。形状对入侵者表面周围的接触分布有影响，这可能会导致某些形状的强烈升力。我们还介绍并讨论了入侵者表面周围的力分布。