论文标题
使用有限元法在粘性流中的刚体运动
Rigid body motion in viscous flows using the Finite Element Method
论文作者
论文摘要
提出了用于使用FEM在粘性流体流中移动的刚体数值模拟的新模型。这种方法最有趣的特征之一是解决刚体的运动所需的小规模努力,与纯流体求解器相当。该模型基于扩展刚体内部的流体速度并以惩罚项来求解流动方程,以实现固体内部的刚性运动。为了获得流体结构域中的速度场,使用分数步骤结合了分数线性动量的两步式泰勒 - 盖尔金(Taylor-Galerkin)的分数步骤,用于不可压缩粘性流的Navier-Stokes方程。一旦计算出流体结构域中的速度场,就可以通过平均固体上平均翻译和角速度来获得刚性运动的计算。处理流体固体相互作用时的主要挑战之一是界面的正确建模,将实体移动质量与粘性流体分开。在这项工作中,提出了用于跟踪流体 - 固定界面的水平设置技术和两步的泰勒 - 盖尔金算法的组合。两步的泰勒 - 加勒金表现出的良好特性,最大程度地减少振荡和数值扩散,使该方法适合于准确地避免固体结构域避免在其边界处造成扭曲,从而保留了刚体的初始尺寸和形状。提出的模型已针对文献中发现的经验解决方案,实验数据和数值模拟进行了验证。在所有测试的情况下,数值结果已证明是准确的,证明了所提出的模型是对流体 - 固定相互作用的数值分析的有价值工具。
A new model for the numerical simulation of a rigid body moving in a viscous fluid flow using FEM is presented. One of the most interesting features of this approach is the small computational effort required to solve the motion of the rigid body, comparable to a pure fluid solver. The model is based on the idea of extending the fluid velocity inside the rigid body and solving the flow equations with a penalization term to enforce rigid motion inside the solid. In order to get the velocity field in the fluid domain the Navier-Stokes equations for an incompressible viscous flow are solved using a fractional-step procedure combined with the two-step Taylor-Galerkin for the fractional linear momentum. Once the velocity field in the fluid domain is computed, calculation of the rigid motion is obtained by averaging translation and angular velocities over the solid. One of the main challenges when dealing with the fluid-solid interaction is the proper modelling of the interface which separates the solid moving mass from the viscous fluid. In this work the combination of the level set technique and the two-step Taylor-Galerkin algorithm for tracking the fluid-solid interface is proposed. The good properties exhibited by the two-step Taylor-Galerkin, minimizing oscillations and numerical diffusion, make this method suitable to accurately advect the solid domain avoiding distortions at its boundaries, and thus preserving the initial size and shape of the rigid body. The proposed model has been validated against empirical solutions, experimental data and numerical simulations found in the literature. In all tested cases, the numerical results have shown to be accurate, proving the potential of the proposed model as a valuable tool for the numerical analysis of the fluid-solid interaction.