Finite-element and smoothed particle hydrodynamics modeling of rigid-object water-entry impact dynamics and validation with experimental results

A numerical study on the dynamic response of a generic rigid water-landing object (WLO) during water impact is presented in this paper. The effect of this impact is often prominent in the design phase of the re-entry project, to determine the maximum force it is subjected to, for material strength determination to ensure structural and equipment integrity, human safety and comfort. The predictive capability of the explicit finite-element arbitrary Lagrangian-Eulerian (ALE) and smoothed particle hydrodynamics (SPH) methods of a state-of-the-art nonlinear dynamic finite-element 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 the 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 results show that the fully coupled FSI models can capture the water-impact response accurately for all range of drop tests considered and the impact accelerations are practically linearly with the increase in the height of the drop. The reliability of the maximum impact accelerations was calibrated with approximate classical von Karman and Wagner closed-form solutions. Copyright © 2010 by ASME.