Objective  This paper aims to study the application effects of heterogeneous supercomputing platforms based on domestic processors in the field of ship hydrodynamics.

  Methods  The direct numerical simulation of the flow around a 3D finite square cylinder with Re = 250 using the Sunway Taihu Light supercomputer is implemented, in which the maximum number of grids is 245.76 million ( t = 600 s, dt = 0.001), and the simulation results are analyzed and verified. The parallel programming method of MPI+Threads is used with a maximum parallel size of 133 120 cores.

  Results  According to the statistics, the calculation can be completed in a few days under the current parallel scale using 245.76 million grids. In addition, the simulation results show that the vortex shedding is synchronous in different cross-sections of a 3D finite square cylinder. When the characteristics of flow around the finite square cylinder with slenderness ratios of 2, 3 and 4 are compared, it is found that when the slenderness ratio is 2, the wake vortex structure of the wake is a long straight streamwise vortex secondary structure, or else it is an antisymmetric Karman vortex.

  Conclusion  These results indicate that multilevel parallel computing using the Sunway Taihu Light supercomputer can effectively reduce the time-consumption caused by grid scale increase in small-scale grids, which has broad application prospects in the field of ship hydrodynamics.