A resolved CFD-DEM-IBM algorithm for water entry problems

A resolved CFD-DEM-IBM algorithm for water entry problems
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DOI：
10.1016/j.oceaneng.2021.110014
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发表时间：
2021-11
期刊：
Ocean Engineering
影响因子：
5
通讯作者：
Yingtang Di;Lanhao Zhao;M. Jia;Avital Eldad
Yingtang Di;Lanhao Zhao;M. Jia;Avital Eldad
中科院分区：
工程技术2区
文献类型：
--
作者：
Yingtang Di;Lanhao Zhao;M. Jia;Avital Eldad

文献摘要

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提出了一种求解CFD-DEM-IBM算法，对入水过程进行了详细的数值描述。离散在固定的笛卡尔网格上，采用Navier-Stokes方程描述复杂的流体行为。用离散单元法(DEM)模拟了固体的运动及其相互作用。采用浸没边界法(IBM)，通过一系列拉格朗日点跟踪剧烈运动的固体边界，并根据速度边界条件求出这些点上的流固相互作用力。用改进的守恒水平集方法捕捉自由面，该方法具有显著的精度和质量守恒性。采用多次迭代的分块格式实现紧耦合流固系统。在可以捕捉到流体相的详细分辨率的情况下，所提出的方法被完全解决，该方法允许以令人信服的精度模拟非均质场之间的相互作用。通过几个算例验证了该算法的可靠性，其结果与已建立的数据吻合较好。在验证后，将所提出的方法应用于模拟多个物体的入水，然后进行层状流体中的颗粒沉降，以显示CFD-DEM-IBM算法对更一般问题的通用性。
A resolved CFD-DEM-IBM algorithm is proposed for elaborate numerical description of water entry process. Discretized on fixed Cartesian grids, the Navier-Stokes equations are adopted to describe the complex fluid behaviors. The motion of solid bodies and their interactions are modeled by the discrete element method (DEM). The immersed boundary method (IBM) is applied to track solid boundaries undergoing drastic movement by a series of Lagrangian points, on which the fluid-solid interaction forces are derived according to velocity boundary conditions. The free surface is captured using the improved conservation level set method which exhibits remarkable accuracy and mass conservation property. The partitioned scheme where several iterations are required is employed to realize tightly coupled fluid-solid system. Shown to be fully resolved where detailed resolution of fluid phase could be captured, the proposed method allows interaction among heterogeneous fields to be modeled with convincing accuracy. Several cases are performed to demonstrate the reliability of the algorithm whose results are in good accordance with the established data. Once validated, the proposed approach is applied to mimic water entry of multiple bodies, and particles settling in stratified fluid is conducted afterwards to reveal the versatility of the CFD-DEM-IBM algorithm for more general problems.