Benchmarking and evaluating the accuracy of a Lattice Boltzmann BGK scheme for multi-fluid flows

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

Lately, the Lattice Boltzmann Method (LBM), as a mesoscopic numerical approach, has received more attention in studying complex fluid flows and transport phenomena. Because of its distinctive advantages over conventional numerical methods, the LBM has achieved great success in a variety of fields since its emergence. The major advantages are referred to its intrinsic linear scalability in parallel computing, and its capability of easily handling complex geometry and boundary conditions. In this study our proposed LB-BGK model, for multi-fluid flows, has been first validated by 2 benchmark problems: 2D Poiseuille flow problem and liddriven cavity flow. Following these simulations, a discussion on the accuracy and the performance of the model is given. Good agreement is obtained with the analytical solution of Poiseuille flow problem, and with the available literature results for 2D lid-cavity. On the other hand, the accuracy of LBM is usually moderated by several factors; hence the effect of different factors is investigated. Among those, we studied the effect of boundary conditions, spatial resolution, Mach number, and that of the choice of relaxation factors. Consequently, LBM was found to be highly dependent on the physical problem, the numerical implementation, and the used models and correlations. In light of the obtained results, we can point out that the LBM may possess high potential in studying fluid flows with complex geometries.