A numerical approach for simulating fluid structure interaction of flexible thin shells undergoing arbitrarily large deformations in complex domains
A numerical approach for simulating fluid structure interaction of flexible thin shells undergoing arbitrarily large deformations in complex domains
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DOI：
10.1016/j.jcp.2015.08.008
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发表时间：
2015-11-01
影响因子：
4.1
通讯作者：
Sotiropoulos, Fotis
中科院分区：
文献类型：
--
作者：
Gilmanov, Anvar;Le, Trung Bao;Sotiropoulos, Fotis
本文提出了一种新的数值方法来模拟不可压缩流体中薄柔性体的流固耦合问题。FSI算法使用Dirichlet-Neumann分割技术。将曲线浸入边界法（CURVIB）与薄壳的无旋转有限元（FE）模型相结合，可以有效地模拟具有任意大变形的流固耦合问题。湍流问题的处理使用大涡模拟与动态Smagorinsky模型结合壁模型重建浸没边界附近的边界条件。CURVIB和FE求解器在柔性固-流界面上耦合在一起，其中计算结构节点位置、位移、速度和载荷并在两个求解器之间交换。采用松耦合和强耦合的FSI格式，通过Aitken加速技术增强，以确保鲁棒耦合和快速收敛，特别是对于低质量比问题。耦合CURVIB-FE-FSI方法通过应用它来模拟两个涉及薄柔性结构的FSI问题进行验证：1）在不同质量比和低雷诺数下安装在方柱尾流中的悬臂的涡致振动; 2）更具有挑战性的高雷诺数问题，涉及倒置弹性旗的振动。对于这两种情况下的计算结果是在良好的协议与以前的数值模拟和/或经验测量。对悬臂梁和倒旗问题进行了网格收敛性试验/研究，结果表明CURVIB-FE-FSI方法具有收敛性。最后，新的方法在模拟复杂的心血管流动的能力证明，通过应用它来模拟FSI的三叶，人工心脏瓣膜在解剖主动脉和生理脉动条件下。(C)2015 Elsevier Inc. All rights reserved.
We present a new numerical methodology for simulating fluid-structure interaction (FSI) problems involving thin flexible bodies in an incompressible fluid. The FSI algorithm uses the Dirichlet-Neumann partitioning technique. The curvilinear immersed boundary method (CURVIB) is coupled with a rotation-free finite element (FE) model for thin shells enabling the efficient simulation of FSI problems with arbitrarily large deformation. Turbulent flow problems are handled using large-eddy simulation with the dynamic Smagorinsky model in conjunction with a wall model to reconstruct boundary conditions near immersed boundaries. The CURVIB and FE solvers are coupled together on the flexible solid-fluid interfaces where the structural nodal positions, displacements, velocities and loads are calculated and exchanged between the two solvers. Loose and strong coupling FSI schemes are employed enhanced by the Aitken acceleration technique to ensure robust coupling and fast convergence especially for low mass ratio problems. The coupled CURVIB-FE-FSI method is validated by applying it to simulate two FSI problems involving thin flexible structures: 1) vortex-induced vibrations of a cantilever mounted in the wake of a square cylinder at different mass ratios and at low Reynolds number; and 2) the more challenging high Reynolds number problem involving the oscillation of an inverted elastic flag. For both cases the computed results are in excellent agreement with previous numerical simulations and/or experiential measurements. Grid convergence tests/studies are carried out for both the cantilever and inverted flag problems, which show that the CURVIB-FE-FSI method provides their convergence. Finally, the capability of the new methodology in simulations of complex cardiovascular flows is demonstrated by applying it to simulate the FSI of a tri-leaflet, prosthetic heart valve in an anatomic aorta and under physiologic pulsatile conditions. (C) 2015 Elsevier Inc. All rights reserved.