Optimizing Power Generation of a Bottom-Raised Oscillating Surge Wave Energy Converter Using a Theoretical Model: Preprint

Nhu Nguyen, Jacob Davis, Krish Thiagarajan, Nathan Tom, Cole Burge

Research output: Contribution to conferencePaper


Preliminary sizing of an oscillating surge wave energy converter (OSWEC) is an iterative process that relies on knowledge of the relevant hydrodynamic coefficients for a given geometry. Often, the complex definition of the device geometry requires coefficients to be obtained through experiments or numerical boundary element solvers such as WAMIT. These techniques demand significant user and computational effort, therefore inhibiting the fine scale parametrization of object dimensions. In this study, a theoretical model, originally presented in Michele et al. (2016), is developed and demonstrated to efficiently optimize the power production for an OSWEC device (subjected to certain environmental conditions) with variations in device widths, heights, and distances from the seabed. Assuming negligible device thickness, the OSWEC motions are modelled as a bottom-raised two-dimensional flap in regular waves using potential flow theory formulated in elliptical coordinates. The solutions to this diffraction-radiation problem are obtained using Mathieu functions with appropriate boundary conditions. The resulting potentials are then used to derive frequency-dependent expressions for the added mass and radiation damping coefficients, along with wave excitation magnitude in surge, pitch, and coupled surge-pitch motions. Good agreement in hydrodynamic coefficient curves is shown between the theoretical model and the numerical results obtained from the boundary element-based program WAMIT. The theoretical model is then employed to maximize the time-averaged output power while maintaining or reducing the hinge reaction force, with variations in device dimensions, wave frequency and amplitude.
Original languageAmerican English
Number of pages13
StatePublished - 2021
Event14th European Wave and Tidal Energy Conference - Plymouth, United Kingdom
Duration: 5 Sep 20219 Sep 2021


Conference14th European Wave and Tidal Energy Conference
CityPlymouth, United Kingdom

Bibliographical note

See NREL/CP-5700-81756 for paper as published in proceedings

NREL Publication Number

  • NREL/CP-5700-79929


  • ACE
  • added moment of inertia
  • hydrodynamic coefficients
  • power production
  • wave energy converter
  • wave excitation
  • wave radiation damping


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