Simulations of Three-dimensional Cavity Flows with Multi Relaxation Time Lattice Boltzmann Method and Graphic Processing Units

2013 ◽  
Vol 61 ◽  
pp. 94-99 ◽  
Author(s):  
Hung-Wen Chang ◽  
Pei-Yao Hong ◽  
Li-Song Lin ◽  
Chao-An Lin
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Cavity Flows ◽  
Graphic Processing Units ◽  
Boltzmann Method ◽  
Graphic Processing

Three-Dimensional Weighted Multiple-Relaxation-Time Pseudopotential Lattice Boltzmann Method for Multiphase Flow

2021 ◽  
Author(s):  
Jun Tang ◽  
Shengyuan Zhang ◽  
Huiying Wu
Keyword(s):  
Relaxation Time ◽  
Multiphase Flow ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Present Model ◽  
Orthogonal Transformation ◽  
Three Dimensional ◽  
Proposed Model ◽  
Multiple Relaxation Time ◽  
Boltzmann Method

Abstract The pseudopotential lattice Boltzmann (LB) method has been widely used for simulating multiphase flow due to its concise concept and computational simplicity. In this paper, based on the weighted orthogonal transformation matrix, a three-dimensional (3D) weighted multiple-relaxation-time pseudopotential lattice Boltzmann method (WRMT-LBM) is developed, in which the standard lattice stencil D3Q19 is adopted. Compared with the classical multiple-relaxation-time pseudopotential lattice Boltzmann method (CMRT-LBM) based on the orthogonal transformation matrix, the expressions of the equilibrium density distribution function and discrete force term in moment space are simplified in the present model, which contributes to simplifying the program implementation and improving the computational efficiency. Moreover, an additional discrete source term in moment space compatible with the proposed model is introduced to achieve tunable surface tension. A series of numerical tests are then implemented to investigate the performance of the proposed model. Compared with the CMRT-LBM, the results of the present model can achieve lower spurious velocity and higher computational efficiency while keeping comparable accuracy. Furthermore, using the present model, three benchmark cases, including droplet oscillation, droplet impacting on wall and droplet impact on thin film, are performed to investigate the performance of this model. The numerical results are in good agreement with the analytical solutions or the empirical correlations in the literature, which demonstrates that the present model can simulate the multiphase flow with large density ratio.

Three-Dimensional Simulation of Balloon Dynamics by the Immersed Boundary Method Coupled to the Multiple-Relaxation-Time Lattice Boltzmann Method

2015 ◽  
Vol 17 (5) ◽  
pp. 1271-1300 ◽  
Author(s):  
Jiayang Wu ◽  
Yongguang Cheng ◽  
Chunze Zhang ◽  
Wei Diao
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Immersed Boundary Method ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Coupling Scheme ◽  
Boundary Method ◽  
Multiple Relaxation Time ◽  
Boltzmann Method

AbstractThe immersed boundary method (IBM) has been popular in simulating fluid structure interaction (FSI) problems involving flexible structures, and the recent introduction of the lattice Boltzmann method (LBM) into the IBM makes the method more versatile. In order to test the coupling characteristics of the IBM with the multiple-relaxation-time LBM (MRT-LBM), the three-dimensional (3D) balloon dynamics, including inflation, release and breach processes, are simulated. In this paper, some key issues in the coupling scheme, including the discretization of 3D boundary surfaces, the calculation of boundary force density, and the introduction of external force into the LBM, are described. The good volume conservation and pressure retention properties are verified by two 3D cases. Finally, the three FSI processes of a 3D balloon dynamics are simulated. The large boundary deformation and oscillation, obvious elastic wave propagation, sudden stress release at free edge, and recoil phenomena are all observed. It is evident that the coupling scheme of the IBM and MRT-LBM can handle complicated 3D FSI problems involving large deformation and large pressure gradients with very good accuracy and stability.

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