A fast moving least squares approximation with adaptive Lagrangian mesh refinement for large scale immersed boundary simulations

JOURNAL OF COMPUTATIONAL PHYSICS

卷:375

Article

Spandan, Vamsi^1,2  Lohse, Detlef^1,2,3  de Tullio, Marco D.⁴  Verzicco, Roberto^1,2,5 

[1] Univ Twente, Phys Fluids, POB 217, NL-7500 AE Enschede, Netherlands

[2] Univ Twente, Max Planck Univ Twente Ctr Complex Fluid Dynam, POB 217, NL-7500 AE Enschede, Netherlands

[3] Max Planck Inst Dynam & Self Org, D-37077 Gottingen, Germany

[4] Politecn Bari, Via Re David 200, I-70125 Bari, Italy

[5] Univ Roma Tor Vergata, Via Politecn, I-00133 Rome, Italy

关键词: Immersed boundary method;    Moving least squares;    Multiphase flows;   

DOI  :  10.1016/j.jcp.2018.08.040

来源: Elsevier

【 摘 要 】

In this paper we propose and test the validity of simple and easy-to-implement algorithms within the immersed boundary framework geared towards large scale simulations involving thousands of deformable bodies in highly turbulent flows. First, we introduce a fast moving least squares (fast-MLS) approximation technique with which we speed up the process of building transfer functions during the simulations which leads to considerable reductions in computational time. We compare the accuracy of the fast-MLS against the exact moving least squares (MLS) for the standard problem of uniform flow over a sphere. In order to overcome the restrictions set by the resolution coupling of the Lagrangian and Eulerian meshes in this particular immersed boundary method, we present an adaptive Lagrangian mesh refinement procedure that is capable of drastically reducing the number of required nodes of the basic Lagrangian mesh when the immersed boundaries can move and deform. Finally, a coarse-grained collision detection algorithm is presented which can detect collision events between several Lagrangian markers residing on separate complex geometries with minimal computational overhead. (C) 2018 Elsevier Inc. All rights reserved.

【 授权许可】

Free