Numerical Investigation of Semi-submersible Floating Wind Turbine Combined with Flap-Type WECs

Abstract

Offshore renewable energy has great potential to meet the increasing energy demands. Ammon different energy source, the offshore wave and wind energy are considered the best possible option as renewable source. To increase renewable energy yield per unit square kilometre of ocean space, there is an increasing interest in investigating the technological and the economic feasibility of combining offshore wind turbines with wave energy converters. In the past two decades, combined concepts of utilizing different floating support platforms and wave energy converters have been studied. In the present study, the hydrodynamic coefficients and response amplitude operators (RAOs) of semi-submersible floater combined with flap-type wave energy converter is analysed. The semi-submersible floater with flap-type wave energy converter is a combined concept of wave and wind energy converters which consists of three elliptical cylinder flap-type wave energy converters (WECs) and a 5 MW floating wind turbine installed on semi-submersible platform. The hydrodynamic coefficients are calculated in frequency domain and the power take off (PTO) system is modelled as a linear damper and spring. A parametric study is made to compute hydrodynamic coefficients of flap and three column semi-submersible platform combined wave and wind energy system. Further, RAO analysis is performed for three column semi-submersible platform relative to combined wave and wind energy platform with incident wave heading angles.