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arXiv 2204.12907math.NAcs.NAmath-phmath.MPphysics.flu-dyn
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一种用于柔性体流固耦合的锐界面拉格朗日-欧拉方法

A sharp interface Lagrangian-Eulerian method for flexible-body fluid-structure interaction

Ebrahim M. Kolahdouz, David R. Wells, Simone Rossi, Kenneth I. Aycock, Brent A. Craven, Boyce E. Griffith

AI总结:

本文提出一种用于柔性体流固耦合的锐界面浸入式拉格朗日-欧拉方法,结合IB方法灵活性与贴体方法精度,采用Dirichlet-Neumann耦合和惩罚法处理流固子问题,支持多速率时间步进,在基准测试和血栓捕获模拟中验证了其有效性。

摘要:

本文引入了一种锐界面方法,用于模拟涉及由一般非线性材料模型描述的柔性体以及大范围质量密度比的流固耦合问题。这种新的柔性体浸入式拉格朗日-欧拉(ILE)方法结合了浸入边界(IB)方法的几何和域求解灵活性,其精度可与锐利解析流场和应力直至流固界面的贴体方法相媲美。与许多IB方法不同,我们的ILE公式对流体和固体子区域使用不同的动量方程,并通过Dirichlet-Neumann耦合策略,通过简单的界面条件连接流体和固体子问题。我们使用涉及流固界面两种表示的惩罚方法。这两种表示通过施加运动学界面条件的近似拉格朗日乘子力连接。这种方法还允许使用多速率时间步进,使我们能够为流体和结构子问题采用不同的时间步长。我们的流体求解器依赖于用于离散表面的浸入界面方法,以沿复杂界面施加应力跳跃条件。体积结构网格的动力学是通过近不可压缩固体力学公式,使用标准有限元方法求解大变形非线性弹性来确定的。对于部分固体边界不接触不可压缩流体的情况,该公式也容易适应可压缩结构。我们与计算和实验基准进行了比较。我们还通过将其应用于模拟下腔静脉滤器中圆柱形血栓的传输和捕获,展示了该方法的能力。

英文摘要:

This paper introduces a sharp-interface approach to simulating fluid-structure interaction involving flexible bodies described by general nonlinear material models and across a broad range of mass density ratios. This new flexible-body immersed Lagrangian-Eulerian (ILE) approach incorporates the geometrical and domain solution flexibility of the immersed boundary (IB) method with an accuracy comparable to body-fitted approaches that sharply resolve flows and stresses up to the fluid-structure interface. Unlike many IB methods, our ILE formulation uses distinct momentum equations for the fluid and solid subregions with a Dirichlet-Neumann coupling strategy that connects fluid and solid subproblems through simple interface conditions. We use a penalty method involving two representations of the fluid-structure interface. These two representations are connected by approximate Lagrange multiplier forces that impose kinematic interface conditions. This approach also enables the use of multi-rate time stepping, which allows us to take different time step sizes for the fluid and structure subproblems. Our fluid solver relies on an immersed interface method for discrete surfaces to impose stress jump conditions along complex interfaces. The dynamics of the volumetric structural mesh are determined using a standard finite element approach to large-deformation nonlinear elasticity via a nearly incompressible solid mechanics formulation. This formulation also readily accommodates compressible structures for cases in which part of the solid boundary does not contact the incompressible fluid. Comparisons are made with computational and experimental benchmarks. We also demonstrate the capabilities of this methodology by applying it to model the transport and capture of a cylindrical blood clot in an inferior vena cava filter.

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