Numerical and Experimental Study of a Spherical Projectile Water Entry Problem and Investigation of Mass and Impact Velocity Effect on Pinch-off Time and Depth

• Main Authors: Mohammad Hossein Taghizadeh Valdi, Mohammad Reza Atrechian, Ata Jafary Shalkoohy, Elham Chavoshi
• Format: Article
• Language: fas
• Published: Iranian Association of Naval Architecture and Marine Engineering 2018-07-01
• Series: نشریه مهندسی دریا
• Subjects: coupled eulerian-lagrangian; spherical projectile; water entry; pinch-off time and depth; viscous energy
• Online Access: http://marine-eng.ir/article-1-662-en.html

The water entry problem of spherical projectile is simulated numerically and experimentally in this study. An explicit dynamic analysis method is employed to model the fluid-structure interaction using a Coupled Eulerian-Lagrangian (CEL) formulation that is available in finite element code Abaqus. The comparison of the numerical simulation results including displacement and velocity variations of spherical projectile in water depth as a function of time, with the theoretical results, indicates a good match between these results and the precision and applicability of the numerical algorithm used. The results reveal that pinch-off time is a very weak function of projectile mass and impact velocity on free water surface; while the pinch-off depth significantly increases along with increased this parameters. Additionally, the projectile mass has a subtle effect on viscous dissipation energy, while increasing the impact velocity on free water surface leads to decrese in dissipation energy.