Analysis of the Parametric Instability of the STC Combined Wind and Wave Energy Concept

Abstract

The purpose of this study is to numerically predict such unstable motions for regular and irregular wave conditions and to compare the results with the experimental observations. First, a literature study on Mathieu instability is carried out to understand the mechanism behind this phenomenon. Then the results of the STC concept from the experiments carried out by Dr. Ling Wan are investigated in order to study the developments of the Mathieu unstable pitch motions and the corresponding wave conditions in which they occur. Finally, a numerical model of Mathieu instability for analysis of the STC pitch motions is established to get insight into the phenomenon. The numerical model is compared with the experimental results of Dr. Ling Wan. A sensitivity study using the numerical model is then carried out to investigate the conditions where the Mathieu instability may occur.