Analysis of the influence of ice-hole constraint on the oblique water-entry characteristics of a high-speed cylinder

Abstract

It is crucial for the water-entry stability and safety of the polar ocean equipment to study the process of the cylinder entering the water and passing through ice holes. In this study, based on the volume of fluid model and Schnerr–Sauer cavitation model, the influences of the ice-hole constraint on the cavity evolution process, the flow field characteristics, and the motion characteristics of the oblique water-entry process of the cylinder under different ice-hole diameter conditions are investigated numerically. The numerical method is verified. Results show that the influence of the ice-hole constraint on cavity evolution is mainly reflected in three aspects: surface splash, cavity wall, and cavity surface closure time. The ice-hole constraint changes the flow range of the water near the free surface, affecting the direction and shape of the surface splashing. The ice-hole inhibits the cavity expansion near the free surface. Under the smaller ice-hole diameter condition, the left-sided cavity wall directly collides with the inner wall of the ice-hole, which causes the curvilinearity of the left wall of the cavity near the free surface. Simultaneously, under the ice-hole condition, the surface closure time of the cavity is altered, and the distribution of the air and vapor inside the cavity is changed. A larger shear deformation region appears near the free surface, and there are more large-scale vortices inside the cavity, which leads to the acceleration of the velocity of the fluid and the decrease in the pressure near the free surface. Moreover, the impact force is changed at the initial stage of the cylinder passing through the ice-hole. The ice-hole condition leads to a faster velocity attenuation and a greater deflection during the oblique water-entry process of the cylinder.