In this paper we describe the fully nonlinear free-surface deformations of initially calm water caused by the water entry and water exit of a horizontal circular cylinder with both forced and free vertical motions. Two-dimensional flow conditions are assumed in the study. This has relevance for marine operations as well as for the ability to predict large amplitude motions of floating sea structures. A new numerical method called the CIP (Constrained Interpolation Profile) method is used to solve the problem. In this paper, the circular cylinder and free surface interaction is treated as a multiphase problem, which has liquid (water), gas (air), and solid (circular cylinder) phases. The flow is represented by one set of governing equations, which are solved numerically on a nonuniform, staggered Cartesian grid by a finite difference method. The free surface as well as the body boundary is immersed in the computational domain. The numerical results of the water entry and exit force, the free surface deformation and the vertical motion of the cylinder are compared with experimental results, and favorable agreement is obtained.

Bubble collapse is one of the leading causes for the cavitation erosion of submerged structures. For better understanding of the destructive mechanism of cavitation, high-fidelity simulation is performed to simulate the complete process of single bubble collapse near a planar solid wall. The wave propagation method with the approximate Riemann solver Harten Lax and van Leer Contact is adopted to solve the compressible two-phase five-equation model. We implement fifth-order weighted essentially non-oscillatory scheme with the block-structured adaptive mesh method to resolve shock waves and moving interface with high-resolution. We simulate single bubble collapsing in free-field to validate the present numerical methods and solver. Our results (e.g., averaged bubble-interior pressure and the radius variation) are found in excellent agreement with the theoretical Keller–Miksis solutions. In this study, the shock wave transmitted inside the bubble and the water-hammer shock formed in the liquid are under quantitative investigation. Numerical results reveal that the interactions between the shock wave and bubble interface give rise to peak pressures of liquid phase, and the initial stand-off distances have important influence on shock wave pattern, wall peak pressure, and bubble dynamics.