Experimental reconstruction of three-dimensional hydrodynamic loading in water entry problems through particle image velocimetry

Abstract

Predicting the hydrodynamic loading during water impact is of fundamental importance for the design of offshore and aerospace structures. Here, we experimentally characterize the 3D hydrodynamic loading on a rigid wedge vertically impacting a quiescent water surface. Planar particle image velocimetry is used to measure the velocity field on several planes, along the width and the length of the impacting wedge. Such data are ultimately utilized to estimate the 3D velocity field in the whole fluid domain, where the pressure field is reconstructed from the solution of the incompressible Navier–Stokes equations. Experimental results confirm that the velocity field is nearly 2D at the mid-span of the wedge, while the axial velocity along the length of the wedge becomes significant in the proximity of the edges. The variation of the fluid flow along the length of the wedge regulates the hydrodynamic loading experienced during the impact. Specifically, the hydrodynamic loading is maximized at the mid-span of the wedge and considerably decreases toward the edges. The method proposed in this study can find application in several areas of experimental fluid mechanics, where the analysis of unsteady 3D fluid–structure interactions is of interest.