The water entry is a classic fluid-structure interaction problem in ocean engineering. The prediction of impact loads on structure during the water entry is critical to some engineering applications. In this paper, a multiphase Riemann-SPH model is developed to investigate water entry problems. In this model, a special treatment, a cut-off value for the particle density, is arranged to avoid the occurrence of negative pressure. A remarkable advantage of the present multiphase SPH model is that the real speed of sound in air can be allowed when simulating water-air flows. In the present work, considering the air effect, several typical water entry problems are studied, and the evolution of multiphase interface, the motion characteristic of structure and complex fluid-structure interactions during the water entry are analyzed. Compared with the experimental data, the present multiphase SPH model can obtain satisfactory results, and it can be considered as a reliable tool in reproducing some fluid-structure interaction problems.

中文翻译：

---

使用多相 Riemann-SPH 模型对考虑空气效应的进水问题进行数值模拟

入水是海洋工程中经典的流固耦合问题。在进水过程中对结构的冲击载荷的预测对于某些工程应用至关重要。在本文中，开发了一个多相 Riemann-SPH 模型来研究进水问题。在该模型中，安排了特殊处理，即粒子密度的截止值，以避免出现负压。当前多相 SPH 模型的一个显着优点是在模拟水-空气流时可以允许空气中的真实声速。在目前的工作中，考虑空气效应，研究了几种典型的入水问题，分析了入水过程中多相界面的演化、结构的运动特征和复杂的流固耦合。