Theoretical Formulation for Oblique Free Surface Impact Emanating from Fluid-Structure Interaction Simulations

Abstract

Slamming is a multiphysics phenomenon characterized by virtually instantaneous, highly concentrated impact pressure fields acting on the outer hull plating of high speed watercraft as they sail into head seas. These types of concentrated pressure impulses can substantially degrade the structural performance of planning hulls and lead to serious ship incidents; even leading to injury and death. The necessity to properly characterize the underlying hydrodynamic and hydroelastic behaviors in the context of slamming, which occur within a confined spatiotemporal window, presents a great challenge in experimental studies. Therefore, a computational approach is undertaken to examine the relation between complex fluid flows and nonlinear structural deformations, resulting from slamming impacts. To this end, a specialized engineering theory of slamming for engineering design is uncovered, and therefore slamming loads can be properly considered within the structural design of high speed watercraft. This dissertation presents computational and theoretical investigations in the context of oblique impact of a flexible plate on a quiescent free surface. The present research comprises three phases: software development, software verification and validation, and theory formulation. In order to properly capture the salient physics accompanying the slamming phenomenology, a high fidelity, implicit, partitioned fluid-structural interaction (FSI) computational solver is developed to carry out the computational experiments in this work. The FSI solver is rigorously verified and validated against numerical and experimental data -- to ensure the software is robust and accurate. The FSI solver is subsequently utilized to examine the interplay between the fluid flow evolutions and elastic plate deformations that occur during slamming. The observations gleaned from FSI simulations are capitalized on to inform a novel, but simple engineering theory describing flexible plates obliquely impacting the water free surface.