- 期刊
NUMERICAL INVESTIGATION OF THE EFFECT OF PROJECTILE MASS AND DROP HEIGHT FROM WATER SURFACE ON PINCH-OFF TIME AND DEPTH
摘要
In this study, the water entry problem of spherical projectile was numerically simulated by the commercial finite element code Abaqus, and the effect of increasing the projectile mass and drop height from free water surface on deepwater displacement, viscous dissipation energy as well as pinch-off time and depth was investigated. An explicit dynamic analysis method was employed to model fluid-structure interactions using a Coupled Eulerian-Lagrangian (CEL) formulation. Accuracy of the numerical methodology and employed algorithm was verified by comparing the numerical results with the available experimental observations including shape of the air cavity and pinch-off time and depth. The results reveal that increasing the spherical projectile mass and drop height from free water surface up to the critical height leads to a decrease in its submersion time from the moment of water surface impact, until it reaches the model bed and greater than the critical drop height has a reverse effect on projectile impact velocity. The pinch-off time is a very weak function of projectile mass and impact velocity on water surface, but the pinch-off depth significantly increases along with increased mass and impact velocity of projectile. Additionally, the projectile mass has a subtle effect on viscous dissipation energy, while increasing the drop height of the projectile above the free water surface leads to a significant decrease in viscous dissipation energy.