Dutt Meenakshi, Behringer R P
Department of Physics and Center of Nonlinear and Complex Systems, Duke University, Durham, North Carolina 27708-0305, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Dec;70(6 Pt 1):061304. doi: 10.1103/PhysRevE.70.061304. Epub 2004 Dec 13.
Experiments performed by Phys. Rev. E 62, 2380 (2000)] on two-particle collisions and dynamics emphasized the importance of the role played by substrate friction, in particular kinetic friction, on the particle dynamics after collisions on a substrate. We present a numerical model which accounts for collisional and surface frictional dissipation and their influence on particle dynamics for a quasi-two-dimensional cooling initially dilute granular material. This model makes the simplifying assumption that the collision dynamics is determined solely by the incoming velocity and angular velocities of the colliding particles. We apply this model to a numerical simulation of a monolayer of monodisperse particles moving on a substrate, enclosed between inelastic walls. We find that surface friction-in particular, kinetic friction-plays a dominant role in determining the dynamics of quasi-two-dimensional multiparticle systems where the particles are in continuous contact with a substrate. Results from simulations performed for different system sizes indicate that surface friction and the inelastic walls lead to clustering of the particles in and near the vicinity of the walls. We find that the rate of decrease of average total kinetic energy is the highest when the majority of the particles have just collided and are experiencing kinetic frictional forces and torques. We also find from our calculations that, on average, particle-wall collisions lead to more dissipation than particle-particle collisions for a single particle for fixed restitutional parameters.
《物理评论E》62, 2380 (2000)所做的关于两粒子碰撞和动力学的实验强调了基底摩擦,特别是动摩擦,对基底上碰撞后粒子动力学所起作用的重要性。我们提出了一个数值模型,该模型考虑了碰撞耗散和表面摩擦耗散及其对准二维冷却初始稀颗粒材料中粒子动力学的影响。该模型做了一个简化假设,即碰撞动力学仅由碰撞粒子的入射速度和角速度决定。我们将此模型应用于在基底上运动、被非弹性壁包围的单分散粒子单层的数值模拟。我们发现表面摩擦,特别是动摩擦,在确定粒子与基底持续接触的准二维多粒子系统的动力学中起主导作用。针对不同系统尺寸进行的模拟结果表明,表面摩擦和非弹性壁导致粒子在壁附近及壁内聚集。我们发现,当大多数粒子刚刚碰撞并受到动摩擦力和扭矩时,平均总动能的下降速率最高。我们从计算中还发现,对于固定的恢复参数,单个粒子与壁的碰撞平均比粒子间碰撞导致更多的耗散。