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arXiv 1805.08643physics.comp-ph
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多相流三维非正交多重弛豫格子Boltzmann模型

Three-dimensional non-orthogonal multiple-relaxation-time lattice Boltzmann model for multiphase flows

Q. Li, D. H. Du, L. L. Fei, Kai H. Luo, Y. Yu

摘要:

在经典的多重弛豫时间(MRT)格子玻尔兹曼(LB)方法中,变换矩阵是通过构造一组正交基向量来形成的。在本文中,理论和数值研究进行调查的能力和效率的非正交MRT-LB模型模拟多相流。首先,提出了一种三维非正交MRT-LB。基于一组非正交基向量,设计了一种非正交MRT碰撞算子,与正交MRT碰撞算子相比,该碰撞算子的变换矩阵及其逆矩阵得到了极大的简化.进一步通过Chapman-Enskog分析,从理论上证明了三维非正交MRT-LB模型在低马赫数极限下能够正确地恢复Navier-Stokes水平的宏观方程。基于赝势多相LB方法,对非正交MRT-LB模型和常规正交MRT-LB模型进行了多相流数值模拟比较。数值结果表明,与通常的正交MRT-LB模型相比,非正交MRT-LB模型在保持数值精度的同时简化了实现。

英文摘要:

In the classical multiple-relaxation-time (MRT) lattice Boltzmann (LB) method, the transformation matrix is formed by constructing a set of orthogonal basis vectors. In this paper, a theoretical and numerical study is performed to investigate the capability and efficiency of a non-orthogonal MRT-LB model for simulating multiphase flows. First, a three-dimensional non-orthogonal MRT-LB is proposed. A non-orthogonal MRT collision operator is devised based on a set of non-orthogonal basis vectors, through which the transformation matrix and its inverse matrix are considerably simplified as compared with those of an orthogonal MRT collision operator. Furthermore, through the Chapman-Enskog analysis, it is theoretically demonstrated that the three-dimensional non-orthogonal MRT-LB model can correctly recover the macroscopic equations at the Navier-Stokes level in the low Mach number limit. Numerical comparisons between the non-orthogonal MRT-LB model and the usual orthogonal MRT-LB model are made by simulating multiphase flows on the basis of the pseudopotential multiphase LB approach. The numerical results show that, in comparison with the usual orthogonal MRT-LB model, the non-orthogonal MRT-LB model can retain the numerical accuracy while simplifying the implementation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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