Numerical analysis of the impact of an inclined plate with water at high horizontal velocity

Abstract

High-speed planing craft, aircraft when ditching into the water, and ground vehicles entering water can experience violent interaction with the water surface that leads to structural failure. The largest loads typically occur over a very short time, but the magnitude of the pressure and force can be extreme and important for design considerations of safe vehicles. In this paper the water entry problem is studied numerically with one-way and two-way-coupled fluid–structure interaction algorithms. One-way simulations assume a rigid structure while solving for the fluid domain solution, whereas the two-way-coupled approach captures the added mass effects by accounting for the plate deformation in the fluid solution. The primary objectives of this study are to present and validate the numerical methodology, and provide insight into the fundamental physical processes that are important for three-dimensional high-speed aircraft ditching and marine-vessel slamming problems. The fluid solution is obtained using the finite-volume discretization of the incompressible Navier–Stokes equations and the volume-of-fluid method to capture the air–water interface. The structural response is obtained using a modal decomposition representation of the dynamic finite-element system. The fluid–structure-interaction framework is validated by comparison with previously published experimental measurements of an aluminum plate that enters the water with a large horizontal-to-vertical velocity ratio. Several test conditions are discussed that ensure that the numerical solver can capture highly localized pressure maxima, the hydrodynamic force, the behavior of the jet-root propagation, and hydroelastic coupling. Simulation results show the capability to accurately capture these complex phenomena which are important to modeling water-entry problems for the design and certification of air-, land-, and water-craft.