Dynamics of the cavity evolution during vertical water entry of deformable spheres

Liu Yang; Yingjie Wei; Cong Wang; Weixue Xia; Jiachuan Li; Zilu Wang; Dehua Zhang

doi:10.1063/5.0051401

Experimental study on the influence of the angle of attack on cavity evolution and surface load in the water entry of a cylinder

Ocean Engineering ◽

10.1016/j.oceaneng.2020.108271 ◽

2021 ◽

Vol 219 ◽

pp. 108271

Author(s):

Tiezhi Sun ◽

Chongbin Shi ◽

Guiyong Zhang ◽

Zhi Zong ◽

Heng Wang

Keyword(s):

Experimental Study ◽

Angle Of Attack ◽

Water Entry ◽

Surface Load ◽

Cavity Evolution

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Experimental study on oblique water entry of projectiles

Modern Physics Letters B ◽

10.1142/s0217984916503486 ◽

2016 ◽

Vol 30 (28) ◽

pp. 1650348 ◽

Cited By ~ 8

Author(s):

Chenggong Zhao ◽

Cong Wang ◽

Yingjie Wei ◽

Xiaoshi Zhang ◽

Tiezhi Sun

Keyword(s):

Experimental Study ◽

Impact Velocity ◽

High Speed ◽

Transition Point ◽

Water Entry ◽

High Speed Photography ◽

Initial Water ◽

Before And After ◽

Velocity Attenuation ◽

Cavity Evolution

An experimental study of oblique water entry of projectiles with different noses has been conducted using high-speed photography technology. The images of the initial water entry impact, cavity evolution, and the closure and shedding of vortices of cavity are presented in the paper. The results reveal that for high-speed oblique water entry (the initial impact velocity [Formula: see text][Formula: see text]50 m/s), the cavity attached to the projectile is symmetrical and free from the influence of gravity. The shedding of the water–vapor–air mixture in the tail of the cavity produces vortices which disappear in the rear of the projectile trajectory. Particular attention is given to the velocity attenuation of the projectile after water entry. The results show that there is a transition point at the time corresponding to the surface seal of the cavity during the velocity attenuation after oblique water entry, and the rates of velocity attenuation are different before and after this transition point. Additionally, the chronophotography of the cavity evolution shows that the time when the surface seal of the cavity occurs decreases with the increase of the initial impact velocity of the projectile.

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Experimental study on water entry of cylindrical projectiles with different nose shapes

Modern Physics Letters B ◽

10.1142/s0217984919501070 ◽

2019 ◽

Vol 33 (09) ◽

pp. 1950107 ◽

Cited By ~ 2

Author(s):

Guo-Xin Yan ◽

Guang Pan ◽

Yao Shi ◽

Guan-Hua Wang

Keyword(s):

High Speed ◽

Flow Characteristics ◽

Cavity Flow ◽

Water Entry ◽

High Speed Photography ◽

Entry Angle ◽

Entry Velocity ◽

Nose Shape ◽

Cavity Evolution ◽

Trajectory Stability

Water entry experiments of projectiles with different nose shapes were performed under different entry angles and velocities using high-speed photography technology. The cavity flow characteristics of the near water surface, including splash jet, splash crown, surface seal of cavity, pull away, deep seal of cavity and cavity collapses, were systematically investigated using a high-speed camera. The emphasis of the study is paid on the effect of nose shape, water entry angle and velocity on the evolution of the air entraining cavity. The experimental results demonstrate that the nose shape of projectile has a significant influence on the jet flow, the cavity diameter and trajectory stability in the case of certain other conditions. On the other hand, the splash scale, cavity diameter increase gradually with the increasing of the water entry velocity, as well as the cavitation closed in advance. Furthermore, the water entry angle of the projectile plays an important role in the cavity evolution and the close type.

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