Dynamic characteristics of water entry under the effect of floating ice and an independent distance model of floating ice

An ice-constrained environment significantly affects the water entry of projectiles. In this paper, cavity evolution in the presence of floating ice is studied. The numerical method is validated by experiments. The effects of the layout of floating ice, Froude number (Fr), and distance between the floating ice and projectile (l_g) on water entry dynamics are investigated. The dynamic model of the water entry under the effect of floating ice is established. The independent distance equation of the floating ice at different Fr is obtained. The results show that the floating ice affects the cavity surface closure and the deep pinch-off. In the presence of unilateral floating ice, the height variation of the splash crown on both sides of the projectile is different, and the height of the splash crown is lower than that under the effect of bilateral floating ice. The impact force of the projectile entering the water is the largest with bilateral floating ice, which is 20% higher than that without floating ice. As Fr increases, the splash crown completely seals on the free surface and the surface closure occurs. With the change of Fr, there are transition regions in the position and time of the cavity pinch-off plots. The effect of the floating ice on the splash crown weakens as l_g increases, and the pressure on both sides of the projectile gradually reaches the pressure without floating ice. The fitted independent distance curve can predict the pressure on both sides of the projectile affected by the floating ice. This study provides a reference for the launch of projectiles and release of detectors in polar region with floating ices, and provides a new idea for water entry under environmental restrictions.