关键词: 舰艇, 水下爆炸, 六方程模型, 可压缩多相流, 黎曼求解器

Abstract: Studying underwater explosions near warships is crucial for hull structure design, explosion impact damage prediction, and personnel safety. To this end, an improved six-equation compressible multiphase flow model based on the diffuse interface method is proposed to resolve thermodynamic state prediction deviation under shock waves and support anti-shock mechanism research and numerical method optimization. The model is improved via a hybrid energy correction equation and a more accurate gas equation of state. A numerical algorithm on an unstructured grid system is constructed, adopting the second-order MUSCL-Hancock scheme (with least-squares reconstruction and Barth-Jespersen limiter) and two-phase HLLC Riemann solver to solve homogeneous hyperbolic equations, and Newton-Raphson iteration for instantaneous pressure relaxation equation. Results show that after total energy equation correction, the model’s simulation of shock wave velocity and interface is highly consistent with the Euler equation’s exact solution, resolving near-interface numerical oscillation. Compared with experimental data, the improved model has a 1.13% relative error and 0.33% higher accuracy; more accurate SG-EOS parameters are obtained by fitting the shock Hugoniot curve. It also clearly shows underwater explosion phenomena: shock wave propagation, bubble expansion-contraction, and bubble collapse water jet. However, it has deficiencies in bubble interface clarity and jet precision, mainly limited by numerical scheme dissipation under extreme gradients. In conclusion, the improved model effectively enhances the accuracy of simulating underwater explosions near naval vessels, supports in-depth warship anti-shock mechanism research, and lays a solid foundation for future numerical method optimization.

Key words: naval vessel, underwater explosions, six-equation model, compressible multiphase flow, Riemann solver