Rigid Object Water Entry Impact Dynamics: Finite Element/Smoothed Particle Hydrodynamics Modeling and Experimental Validation

Abstract

A numerical study on the dynamic response of a generic rigid waterlanding object (WLO) during water impact is presented in this paper. The effect of this impact is often prominent in the design phase of the reentry project to determine the maximum force for material strength determination to ensure structural and equipment integrity, human safety and comfort. The predictive capability of the explicit finiteelement (FE) arbitrary LagrangianEulerian (ALE) and smoothed particle hydrodynamics (SPH) methods of a stateoftheart nonlinear dynamic finiteelement code for simulation of coupled dynamic fluid structure interaction (FSI) responses of the splashdown event of a WLO were evaluated. The numerical predictions are first validated with experimental data for maximum impact accelerations and then used to supplement experimental drop tests to establish trends over a wide range of conditions including variations in vertical velocity, entry angle, and object weight. The numerical results show that the fully coupled FSI models can capture the waterimpact response accurately for all range of drop tests considered, and the impact acceleration varies practically linearly with increase in drop height. In view of the good comparison between the experimental and numerical simulations, both models can readily be employed for parametric studies and for studying the prototype splashdown under more realistic field conditions in the oceans.