arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2003.12046math.NAcs.NA
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刚体流固耦合问题的锐界面拉格朗日-欧拉方法

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

Ebrahim M. Kolahdouz, Amneet P. S. Bhalla, Lawrence N. Scotten, Brent A. Craven, Boyce E. Griffith

摘要:

本文介绍了一种模拟刚体在粘性不可压缩流体中的流固耦合问题的锐界面方法。这种方法的能力证明了一系列的基准测试案例,以及大规模的生物医学FSI模型。本文中开发的数值方法,我们称之为浸没拉格朗日-欧拉方法,通过求解流体和固体子域的单独动量方程,集成了分区和浸没FSI制剂的各个方面,如在分区制剂中,同时还使用动态流体和结构区域的非一致离散化,如在浸没制剂中。一个狄利克雷-诺依曼耦合方案,其中的运动的浸没固体被驱动的流体牵引力沿流体-结构界面评估,和沿该界面的流体的运动被约束,以匹配固体速度,从而满足无滑移条件。为了发展一种实用的数值方法,我们采用了一种惩罚方法,近似地施加沿流体-结构界面的无滑移条件。我们的流体-结构相互作用方案依赖于离散几何形状的浸没界面方法,该方法能够准确确定复杂流体-结构界面的速度和应力。不像常用的分区FSI方法,这可能会遭受所谓的附加质量效应不稳定性,我们的方法保持稳定的测试用例,涉及非常小,几乎相等,相等,和大的固体-流体密度比,而不需要subiterations或复杂的处理的压力。生物医学FSI示范案例也包括在脉冲复制器的双叶机械心脏瓣膜的动力学,并在下腔静脉的患者平均解剖模型的血凝块的运输。

英文摘要:

This paper introduces a sharp interface method to simulate fluid-structure interaction (FSI) involving rigid bodies immersed in viscous incompressible fluids. The capabilities of this methodology are demonstrated for a range of benchmark test cases along with large-scale models of biomedical FSI. The numerical approach developed herein, which we refer to as an immersed Lagrangian-Eulerian method, integrates aspects of partitioned and immersed FSI formulations by solving separate momentum equations for the fluid and solid subdomains, as in a partitioned formulation, while also using non-conforming discretizations of the dynamic fluid and structure regions, as in an immersed formulation. A Dirichlet-Neumann coupling scheme is used, in which the motion of the immersed solid is driven by fluid traction forces evaluated along the fluid-structure interface, and the motion of the fluid along that interface is constrained to match the solid velocity and thereby satisfy the no-slip condition. To develop a practical numerical method, we adopt a penalty approach that approximately imposes the no-slip condition along the fluid-structure interface. Our fluid-structure interaction scheme relies on an immersed interface method for discrete geometries, which enables the accurate determination of both velocities and stresses along complex fluid-structure interfaces. Unlike commonly used partitioned FSI methods, which can suffer from so-called added mass effect instabilities, our methodology retains stability for test cases involving extremely small, nearly equal, equal, and large solid-fluid density ratios without requiring subiterations or complex handling of the pressure. Biomedical FSI demonstration cases are also presented including the dynamics of a bileaflet mechanical heart valve in a pulse duplicator, and transport of blood clots in a patient-averaged anatomical model of the inferior vena cava.

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