Tension of Catenary and Taut Mooring Lines on One-body and Two-body Point Absorber with Low Wave Condition

Abstract

Mooring lines systems for point absorber, wave energy converters (WECs) devices, must be engineered to withstand the cyclical loads and motions generated by the interaction of the wave load, as well as the WEC's motions in the random elevation of the sea surface. A simulation model was developed and validated concerning the simulated of point absorber motioned in a previous study; this study compares tension methodologies for point absorber with moorings lines using simulation approach. The purpose of this paper is to propose a mooring lines simulation approach that is suited for a one-body and two-body point absorber thorough examination of the heave motion response and, tension analysis of mooring lines coupled on the device and on seabed. The case study is a cylindrical, floating point absorber with one, two, three and four distributed mooring lines with catenary and taut configurations. The dynamics of the point absorber were simulated and analysed in the time domain using different configurations of mooring lines using Computational Fluid Dynamic (CFD) simulation approaches were compared. A thorough response analysis is undertaken using a Malaysia low wave condition in shallow water. The results were compared to the assessed for both one and two-body point absorber methods. The simulation process employing a two-body with four mooring lines recommended as the preferred method for capturing the interaction between the WEC system's components, which has been demonstrated to be critical for heaving response evaluation. The average maximum tension on four mooring lines with catenary configuration is preferred to have less tension with high heaving response of the device compared to others. The findings showed that a two-body point absorber with four catenary mooring lines average maximum tension of 700 N is more efficient at absorbing low wave heights than a single body.