Fluid-structure interaction effects resulting from hull appendage coupling

Abstract

In previous work conducted in the modeling and simulation of ships subjected to underwater explosions, there has been some debate over the influence that hull appendages have upon the dynamic response of a multi-degree-of-freedom structural model surround by a fluid mesh. This thesis investigates the effects on the dynamic response of a structural model resulting from the inclusion of hull appendages such as rudders, shafts and keel boards. Moreover, it examines the differences resulting from these appendages having been modeled as coupled or uncoupled structures with respect to the surrounding fluid in the finite element analysis. In this case, a Meko-like box model, based on the actual dimensions of a typical Meko-class ship, was investigated using the underwater shock modeling and simulation methodology developed at the Naval Postgraduate School's Shock and Vibration Computational Laboratory. Presented herein is a detailed study on the validity of including hull appendages, the proposed coupling scheme for these appendages, and the resulting effects on the vertical and athwartship velocity response motions.