Numerical simulation of water entry of an inclined cylinder

Abstract Water entry of cylindrical structures is a complex multiphase flow problem involving a three-phase medium interaction that occurs instantaneously. It is a nonlinear and unsteady process, which the physical understanding of mechanism in the aspect of evolution of cavity dynamics and multiphase flow field is yet to be fully understood. In the present work, a three-dimensional numerical model of six degrees of freedom (DOF) based on the shear stress transport (SST) k − ω eddy viscosity model was established to capture the complicated characteristics of the vertical water entry of an inclined cylinder at various entry velocities. A volume of fluid method for tracking air-water interface and a combined dynamic fluid body interaction and overlapping grid technology were used to simulate the complex motion. The numerical model with laminar and turbulent model was verified against the published experimental data of cavity evolution and motion characteristics. A parametric study was conducted to study the translational and rotational characteristics of the structure due to the effect of water entry velocity. The investigation revealed the secondary closure phenomenon during the water entry. The asymmetrical multiphase flow field showed that its dynamic characteristics change with space and time under the effect of cavity evolution.