Experimental Analysis and Reduced Order Modeling of Wedge Water Entry with Fluid-Structure Interactions

The problem of wedge water entry is wide-ranging, with applications that extend from understanding the impact on high-speed crafts at sea, to studying how birds dive into water, and even to examining the splashdown dynamics of spacecraft. This talk will systematically investigate the role of flexural rigidity on spray root and pressure wave propagation through a series of wedge water entry experiments and reduced-order model predictions. Measurements of hydrodynamic surface pressures along the wedge, spray root location, structural deflection, and rigid body kinematics will be presented for five flexural rigidity conditions. Experimental observations will be compared to predictions from a reduced-order fluid-structure model that couples a nonlinear hydrodynamic solver with an Euler-Bernoulli beam finite element solver. The talk will show self-similarity of the nondimensionalized spray root position over time, despite three orders of magnitude variation in the panel flexural rigidity. Additionally, the times of arrival of pressure waves at each sensor on the panel's bottom, normalized by the hydroelasticity factor, remain constant at each nondimensional location along the panel.