Hybrid MPI/OpenMP parallel implementation for simulating the water-exit and ice-breaking process of a ventilated underwater vehicle

Large-scale numerical simulation of the ice-breaking and water exit process of underwater vehicles requires substantial computational resources due to the strong coupling among multiphase flow, vehicle motion, and ice fracture. To improve computational efficiency, a hybrid MPI/OpenMP parallel strategy is implemented by combining two-dimensional domain decomposition with shared-memory multithreading. The parallel performance is evaluated over a wide range of process and thread configurations. The results show that pure MPI parallelization provides good scalability at low process counts in this study, whereas communication overhead limits performance at large scales. The hybrid MPI/OpenMP approach consistently achieves shorter wall-clock time by reducing inter-process communication and enhancing intra-node parallelism, despite a decrease in strong-scaling efficiency. The results obtained on the tested computing platform indicate that the proposed framework can efficiently perform large-scale ice-breaking water exit simulations.