Thermal-hydrodynamic coupling and cavity dynamics of high-speed projectiles traversing a submerged ice hole

Abstract

Reliable deployment of underwater sensing systems in ice-covered polar seas requires a comprehensive understanding of projectile penetration through pre-drilled ice openings under low-temperature conditions. A thermodynamic cavitation framework is extended to account for temperature-dependent phase-change effects during high-speed water entry, and its capability in describing cryogenic cavitation is assessed against benchmark experimental measurements. The extended framework is subsequently applied to investigate high-velocity water entry in polar environments, with particular emphasis on the coupling between thermodynamic cavitation, cavity evolution, and temperature-dependent fluid properties. The water-entry behavior of a projectile passing through a submerged ice hole is further examined, and the influences of environmental temperature and Froude number on cavity evolution, flow-field development, and projectile dynamics under ice-hole confinement are analyzed. The results show that cryogenic conditions modify cavity development through coupled changes in liquid thermophysical properties and vapor generation. Reduced ambient temperature promotes earlier cavity collapse events, including near-surface sealing and downstream pinch-off. Under ice-hole confinement, surface closure is relatively insensitive to temperature, whereas deep pinch-off occurs earlier at lower temperatures. As the Froude number increases, the constraining effect of the ice hole on cavity size weakens, while the influence of temperature on cavity evolution during deep pinch-off becomes more pronounced. In addition, the present model predicts an increase in projectile resistance during penetration through the ice hole as temperature decreases. These results provide new physical insight into the coupled effects of low-temperature thermodynamic cavitation and geometric ice-hole confinement on high-speed water entry and offer guidance for underwater detector deployment in polar environments.