Fully coupled analysis for wave induced responses of movable wave energy converter with link connection and oscillating water column

Abstract

A new movable wave energy converter of VLCO (Variable Liquid Column Oscillator) type was proposed by KEPRI (Korea Electric Power Research Institute). The VLCO system has two main units in which oscillating water column air chamber are installed and those two bodies are connected with linked PTO (Power Takeoff). This paper numerically investigates wave induced motions and loads of the VLCO system considering fully coupled behavior of floating body, link connection and internal chamber sloshing. Hydrodynamic coefficients and forces of governing equation are formulated using HOBEM (Higher Order Boundary Element Method) and modified equation of motion is derived using equivalent spring-damper model and ART (Anti-Rolling Tank) model to describe link connection and air chamber sloshing, respectively. Wave and sloshing induced motions of VLCO and resultant forces at PTO connection are calculated. The effect of PTO damping and air chamber size are also investigated. Copyright ？ 2011 by the International Society of Offshore and Polar Engineers (ISOPE).