Session: 09-02-03: Wave Energy - Design and Performance Analysis 2

Paper Number: 101335

101335 - Fsi Simulations and Analyses of a Non-Resonant Buoyant Wave Energy Converter 

To a more considerable extent, the production and supply of electricity to society and industries will come from a combination of marine renewable energy sources, e.g., offshore wind, floating solar photovoltaic power plants, ocean currents, and tidal and wave energy. Wave energy is yet a renewable source of energy which has not been made commercial. Many concepts have been developed and tested on a laboratory scale, some large-scale prototypes have been built and tested, and some technologies will soon be ready for the commercial market of electricity production. The backbone in developing these technologies has been numerical models and simulations, which through numerical analyses, have supported the designers in understanding the technologies’ characteristics in the development stage. Fluid-structure-interaction (FSI) effects are not considered fully or accurately by all numerical tools. The shape and size of the buoy, the moorings, and the power-take-off system of many WECs require that FSI is considered for accurate predictions.

This study presents fully coupled hydrodynamic-structure response simulations and analyses of a novel heave-point absorber WEC developed by NovigeAB. The simulations have been carried out in the DNV software package SESAM. The WEC concept is a non-resonant buoyant wave energy converter that extracts energy from the vertical motion (heave) of the waves. The WEC has a rectangular buoy of pontoon shape with a curved profile on the side facing the oncoming waves. The buoy is moored to the seabed by four elastic polyester moorings through four submerged floaters. The simulation model, its motion characteristics, and mooring forces of one buoy are established as a reference model for time-domain simulations of several sea states. A two-buoy simulation model is thereafter presented. Interaction effects between the two buoys are investigated in a parametric study by varying the sea state conditions and the distances between the buoys sideways and downstream to the wave encounter direction. The buoys’ motions and the mooring forces are compared with the reference single buoy model. A discussion regarding accuracy in simulation methods is presented, using the single WEC model, by comparing the simplified FSI coupling in the SESAM software with results from a high-fidelity simulation model using a CFD code.

Presenting Author: Jonas W Ringsberg Chalmers University of Technology

Presenting Author Biography: Professor of Marine Structures

Authors:

Xinyuan Shao Chalmers University of Technology
Hua-Dong Yao Chalmers University of Technology
Jonas W Ringsberg Chalmers University of Technology
Jan Skjöldhammer Novige AB
Jianfeng Lin Chalmers University of Technology