Recent Additions in the Modeling Capabilities of an Open-Source Wave Energy Converter Design Tool

WEC-Sim is a midfidelity numerical tool for modeling wave energy conversion devices. The tool's code employs the MATLAB SimMechanics package to solve multibody dynamics and model wave interactions using hydrodynamic coefficients derived from frequency-domain boundary-element methods. This paper presents the new modeling features introduced in the latest release of WEC-Sim. The first feature is conversion of the fluid memory kernel to a state-space form. This enhancement offers a substantial computational benefit after the hydrodynamic body-to-body coefficients are introduced and the number of interactions increases exponentially with each additional body. Additional features include the ability to calculate the wave-excitation forces based on the instantaneous incident wave angle, allowing the device to weathervane, as well as import a user-defined wave elevation time series. A review of the hydrodynamic theory for each feature is provided and the successful implementation is verified using test cases.