Experimental Study on the Cavity Evolution Characteristics of Projectile Obliquely Entering Water under Ice Hole Constraint Environment
The effect of ice hole constraint environment on the cavity evolution of projectile entering water is studied. A projectile oblique water entry experiment with different ice hole diameters is carried out based on high-speed camera technology. Through comparative analysis of the oblique water entry process of projectile under ice-free conditions and ice hole constraint,the cavity evolution of projectile entering water is divided into three stages:cavity expansion,cavity surface closure,and cavity deep closure,and the law of influence of ice hole constraint on the cavity evolution of projectile obliquely entering water is summarized. The results show that,in the stage of cavity expansion,the cavity expansion is constrained by the ice hole,and the left side of the cavity near the free liquid surface is curved. On the one hand,the liquid near the water entry point moves around and impacts the ice plate,which consumes part of the energy used for cavity expansion. On the other hand,the displaced liquid impacts the inner edge of ice hole to form a reflected flow,and the direction of the reflected flow is opposite to the direction of the cavity expansion,which further restricts the expansion of cavity. When the diameter of ice hole is small,the cavity wall has the folds on its right side due to the impact of reflected flow. With the increase in the ice hole diameter,the curvature of the left side profile of the cavity gradually weakens. In the closure stage of the cavity surface,the folded cavity wall collapses with local impact,and the reflected flow becomes thinner and weaker with the increase in the diameter of ice hole. In the deep closure stage of the cavity,the reflected flow impacts the cavity under the constraint of ice hole,which makes the pressure difference between the inside and outside of cavity larger and accelerates the deep closure of the cavity. When the diameter of ice hole is small,the local impact collapse is stronger,which is integrated with the tail shedding collapse. With the increase in the diameter of ice hole,the local impact collapse,closed jet and reflected flow are independent of each other,whics is gradually approach the ice-free condition.
projectileoblique water entrywater entry experimentice hole constraint environmentcavity evolution
万方数据
维普
