Progress on simulating nonlinear free-surface flows with Lattice Boltzmann method

Free-surface flow is one of the classical topics in ship hydrodynamics research field. Strongly nonlinear phenomena could be found in many free-surface flows such as slamming, water-entry, deck wetness and so on. Such flows include both macroscopic character changes such as ship motion and microscopic character variation such as splashing. In order to simulate those nonlinear free-surface flows, the numerical method chosen should not only have the capability to simulate the free-surface but also to handle the large-scale-computation. Lattice Boltzmann Method was chosen in this paper to simulate those free-surface flows. Single-phase free-surface model developed by Thtiery was chosen to simulate the free-surface. Large eddy simulation was used to handle high Reynolds number situation. The code was developed with MPI and Cuda to adapt to HPC and GPU calculating acceleration. Some typical nonlinear free-surface flows were simulated. Such as wedge slamming, Oblique water entry of cylinder, half immersed propeller running, vehicle running on free-surface. It was found that LBM was well performed in parallel computing. It just took few days to finish one simulation case with billion Lattices in hundreds threads parallel computing. High fineness characteristics of free-surface evolution could be obtained during simulation. The results show that LBM has great potential for solving nonlinear free surface flows issues.