In such methods, the grid is distributed to provide appropriatelocal resolution, but in order to avoid severe mesh distortion, grid regeneration is usually needed every few time steps. In contrast,the methods based on the nonbodyconformal Cartesian grid such as the immersed boundary method (IBM) and the lattice Boltzmann method (LBM) have increasingly received much attention in recent years as they are essentially simpler in handling the complex and moving geometries.