PREDICTING WAVE-INDUCED LOADS IN COMPLEX SEAWAYS ON SHALLOWLY SUBMERGED VESSELS

Abstract

This thesis analyzes the validity of using linear superposition to accurately predict the forces and moments on a shallowly submerged vessel in a complex seaway. Linear superposition implies that the forces and moments due to the complex seaway are simply the summation of the forces and moments of the single regular waves that combine to create the complex seaway. The forces and moments are measured on a UUV-shaped model in the tow tank with wave making capability at the Naval Postgraduate School with the aid of various data collection processes. First, the forces and moments due to single regular waves are studied. Single regular wave results are then combined to predict what complex waveform loads would be and the accuracy is assessed. The results show that linear superposition is a valid assumption over the wave heights and frequencies tested, especially for wavelengths greater than the length of the submerged body when the submerged depth is twice the diameter of the body.