根据流固耦合问题的普遍性,提出了基于浸入边界法的高解析度计算流体力学-离散元法(CFD-DEM)流固耦合方法.新方法采用基于欧拉框架的计算流体力学方法描述流体的运动,采用基于拉格朗日框架的离散元法描述固体的运动及碰撞,在离散单元的表面布置浸入边界点,解决固体运动过程中与流体间的移动且未知的边界问题.为验证方法的准确性,模拟了圆柱绕流涡激振动、方块驰振两个经典算例,计算结果与数值解吻合度高,说明新方法能够准确描述流固耦合作用.最终,将该方法应用于多块体沉降的模拟,结果表明新方法能够反映流场的复杂变化,有效处理包含大量任意形状离散块体碰撞的流固耦合问题.

Based on the immersed boundary method, a resolved CFD-DEM algorithm is proposed to tackle fluid-solid interaction problems which widely exist. In the proposed method, the fluid filed is described by the computational fluid dynamics in the Eulerian framework, while the movement and collision of the solids are simulated by the discrete element method in the Lagrangian framework. In order to deal with the moving interfaces between the fluid and the solids, several immersed boundary points are allocated on the boundaries of the solids. Two classic test cases are calculated to verify the accuracy of the proposed method, including the vortex-induced vibration of a cylinder and the rotational galloping of a rectangular rigid body. Good agreements are achieved between the current results and those in previous references and the reliability of the present method in modelling the fluid-solid interaction problems are proved. Finally, the sedimentation of multiple solids is simulated and the ability of the proposed CFD-DEM method in solving the complex fluid field and the collision among the solids with arbitrary shapes are verified.