Preliminary investigation of the effects of a trapezoidal moonpool on the hydrodynamic performance of the Barge-Type FOWT substructures for potential OWC integration

Abstract

This paper aims to examine the effects of the geometry of the moonpool of a barge-type Floating Offshore Wind Turbine (FOWT) substructure on the operation of an Oscillating Water Column (OWC) wave energy capture system installed inside the moonpool. The analysis takes into consideration the piston-like water oscillation relative to the heave motion as the main criteria for evaluating the operation of the OWC system. To achieve this, a numerical model was developed in OpenFOAM to simulate a barge-type FOWT substructure, utilizing coupled overset-volume of fluid methods. The barge-type FOWT substructure with a trapezoidal moonpool featuring different sizes and inner-sidewall angles was modeled against waves with varying wave frequencies. Based on the obtained results, trapezoidal square moonpools with sidewall angles of 80 and 100° are identified as favorable options relative to those with vertical walls, enhancing the operation of the OWC system across different ranges of wave frequencies.