An efficient phase-field method for turbulent multiphase flows

JOURNAL OF COMPUTATIONAL PHYSICS

卷:446

Article

Liu, Hao-Ran^1,2,3  Ng, Chong Shen^1,2,3  Chong, Kai Leong^1,2,3  Lohse, Detlef^1,2,3,4  Verzicco, Roberto^1,2,3,5,6 

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

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

[3] Univ Twente, JM Burgers Ctr Fluid Dynam, POB 217, NL-7500 AE Enschede, Netherlands

[4] Max Planck Inst Dynam & Self Org, Fassberg 17, D-37077 Gottingen, Germany

[5] Univ Roma Tor Vergata, Dipartimento Ingn Ind, Via Politecn 1, I-00133 Rome, Italy

[6] Gran Sasso Sci Inst, Viale F Crispi 7, I-67100 Laquila, Italy

关键词: Turbulence;    Multiphase flow;    Phase-field method;    Biharmonic term;    High performance computation;   

DOI  :  10.1016/j.jcp.2021.110659

来源: Elsevier

【 摘 要 】

With the aim of efficiently simulating three-dimensional multiphase turbulent flows with a phase-field method, we propose a new discretization scheme for the biharmonic term (the 4th-order derivative term) of the Cahn-Hilliard equation. This novel scheme can significantly reduce the computational cost while retaining the same accuracy as the original procedure. Our phase-field method is built on top of a direct numerical simulation solver, named AFiD (www.afid.eu) and open-sourced by our research group. It relies on a pencil distributed parallel strategy and a FFT-based Poisson solver. To deal with large density ratios between the two phases, a pressure split method [1] has been applied to the Poisson solver. To further reduce computational costs, we implement a multiple-resolution algorithm which decouples the discretizations for the Navier-Stokes equations and the scalar equation: while a stretched wall-resolving grid is used for the Navier-Stokes equations, for the Cahn-Hilliard equation we use a fine uniform mesh. The present method shows excellent computational performance for large-scale computation: on meshes up to 8 billion nodes and 3072 CPU cores, a multiphase flow needs only slightly less than 1.5 times the CPU time of the single-phase flow solver on the same grid. The present method is validated by comparing the results to previous studies for the cases of drop deformation in shear flow, including the convergence test with mesh refinement, and breakup of a rising buoyant bubble with density ratio up to 1000. Finally, we simulate the breakup of a big drop and the coalescence of O (10(3)) drops in turbulent Rayleigh-Benard convection at a Rayleigh number of 10(8), observing good agreement with theoretical results. (C) 2021 The Author(s). Published by Elsevier Inc.

【 授权许可】

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