论文标题
流体粒子的相互作用方案在浊流演变中从耦合的LES/DEM模型演变
Fluid-particle interaction regimes during the evolution of turbidity currents from a coupled LES/DEM model
论文作者
论文摘要
在本文中，使用结合LES和DEM的模型（大涡模拟和离散元素方法）研究了平床上锁定浊度电流（TC）中的流体粒子相互作用。通过将数值溶液与前位置的测量，流体速度曲线以及锁交换TC的颗粒浓度曲线进行比较，可以证明该模型的可靠性。获得以下身体理解。涡度场通过影响在颗粒上作用的流体提升力（即，在与流体粒子滑动速度正常的方向上，涡度场对当前进化起着重要作用。一开始，由于强质量涡度而引起的纵向正升力会促进纵向颗粒的转运。之后，纵向升力力降低并最终变为负，甚至超过了正纵向阻力的大小，因为越来越多的沉降颗粒会受到底部壁上底部摩擦引起的负涡度的影响。有趣的是，尽管流体粒子相互作用力的复杂行为及其在TC进化中的作用，但实际上只有很小的一部分初始粒子重力势能转化为TC动能（粒子和流体）。
In this paper, fluid-particle interactions in lock-exchange turbidity currents (TCs) over a flat bed are investigated using a model combining LES and DEM (Large-Eddy Simulation and Discrete Element Method). The reliability of this model is demonstrated via comparing the numerical solutions with measurements of the front positions, fluid velocity profile, and particle concentration profile of lock-exchange TCs. The following physical understandings are obtained. The vorticity field plays an important role for the current evolution by affecting the fluid lift force (i.e., in the direction normal to the fluid-particle slip velocity) acting on the particles. At the very beginning, a longitudinal positive lift force due to strong positive vorticity promotes longitudinal particle transport. Afterwards, the longitudinal lift force decreases and eventually becomes negative, with a magnitude that even exceeds that of the positive longitudinal drag force, because more and more of the settling particles are affected by the negative vorticity near the bottom wall caused by surface friction. Interestingly, in spite of the complex behavior of the fluid-particle interaction forces and their role in TC evolution, only a very small fraction of the initial particle gravitational potential energy is actually transformed into TC kinetic energy (both particle and fluid).
