(455b) A Lattice Boltzmann Method with Adaptive Mesh Refinement for Direct Simulation of Bubble Dynamics

The lattice Boltzmann method (LBM) for two-phase flow simulation is often hindered by insufficient resolution at the gas-liquid interface. As a result, the LBM simulation of bubbles is commonly limited to spherical or slightly deformed bubble shapes. In this study, the adaptive mesh refinement (AMR) method for the LBM is developed to overcome such a problem. The approach for this new method is based on the improved interaction potential model, which is able to maintain grid-independent fluid properties in the two fluid phases and at the interface. The LBM-AMR algorithm is described, especially concerning the LBM operation on a non-uniform mesh and the improved interaction potential model. Numerical simulations have been performed to validate the method in both single phase and multiphase flows. The 2D and 3D simulations of the buoyant rise of bubbles are conducted under various conditions. The agreement between the simulated bubble shape and velocity with experiments illustrates the capability of the LBM-AMR approach in predicting bubble dynamics even under the large bubble deformation conditions. Further, the LBM-AMR technique is capable of simulating a complex topology change of the interface. Integration of LBM with AMR can significantly improve the accuracy and reduce the computation cost. The method developed in this study may appreciably enhance the capability of LBM in the simulation of complex multiphase flows under realistic conditions.