TEAMER: Numerical Modeling, Analysis, and Optimization of Oscillo-Drive Wave Energy Converter

A numerical modeling and optimization framework has been developed for the Oscillo-Drive Wave Energy Converter (WEC) being developed by Wave Water Works LLC, with technical assistance from Florida Atlantic University under the DOE TEAMER program. The primary objective was to establish a wave-to-wire modeling capability to investigate the influence of float geometry, submergence level, power take-off (PTO) characteristics, and sea-state conditions on device performance.

This was achieved by integrating Capytaine, BEMIO, WEC-Sim, MATLAB, and WECOPTtool into a unified workflow spanning hydrodynamic analysis (boundary-element generation of hydrodynamic coefficients), time-domain simulation, and system optimization under both regular and irregular wave conditions. Hydrodynamic coefficients (added mass, radiation damping, and RAO) were validated against Hulme's (1982) exact semi-analytic solution for a floating hemisphere, agreeing to within 0.5-1% across the tested frequency range, with independent mesh-convergence and self-consistency checks confirming numerical accuracy.

The study found that absorbed power is governed by the combined interaction of float diameter and arm length rather than either parameter alone, with the optimal geometry shifting with wave period (e.g., ~0.20 m diameter/0.60 m arm at a 3 s period vs. ~0.25 m/0.60 m at 7 s); that submergence ratio has only a secondary effect on best-achievable power, with values across h/d = 0.25-0.75 stayed within about 16% of one another once geometry was re-optimized for each case, despite strongly affecting resonance sharpness; that PTO damping must be impedance-matched to the hydrodynamic radiation damping, with both under- and over-damped conditions reducing output; and that realistic irregular sea states shift the optimal design relative to regular waves and reduce achievable power in longer-period, higher-energy conditions, reflecting a mismatch with the float-size range tested. Across all cases examined, the Oscillo-Drive arm's mechanical sweep-angle limit was the binding design constraint, relaxing it from 30 to 60 degrees roughly quadrupled deliverable power.

These results demonstrate that the workflow is a reliable and scalable approach for the analysis and optimization of small-scale wave energy converters.

This project is part of the TEAMER RFTS 13 (request for technical support) program.