Experimental Determination of Energy Absorption Characteristics of a Cylindrical Wave Energy Converter in Linear and Nonlinear Waves

Abstract

Wave Energy Converters (WEC's) are devices that extract the energy stored in ocean waves and convert it into useful energy, like electricity. A cylindrical WEC was tested in both 1-degree-of-freedom (DOF) and 2 DOF configurations. The first set of experiments were performed with a 1 DOF system featuring mechanical springs which provided passive restoring forces. The second set of 1 DOF experiments and all of the preliminary 2 DOF trials were done with an actuated gantry. This gantry allowed for the control forces applied on the cylinder to be changed via software rather than by switching out mechanical hardware. During trials with wave amplitudes ranging from 0.75 inches to 1.5 inches and wave periods between 0.5 and 2.5 seconds, the hydrodynamic forces acting on the cylinder caused it to oscillate and absorb a fraction of the incident wave energy. The maximum energy available for extraction from the oscillator was 35 percent in the mechanical 1 DOF configuration, which occurred at the resonant wave period of 1.48 s and a wave amplitude of 0.75 in. Measurements of available energy for 1 DOF and 2 DOF tests with the gantry system are in the initial stages, as the presence of significant system frictional damping caused all experiments to have an overdamped response. However, the addition of a second degree of freedom caused an increase in available energy by a factor of around two (as compared to the 1 DOF gantry tests). Future work will consist of deducing an accurate model of gantry friction to allow the control system to properly account for it during experiments.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
May 16, 2026
Accession Number
AD1207044

Entities

People

  • Ryan M. Conway

Organizations

  • United States Naval Academy

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Boundary Layer
  • Buoyancy
  • Data Analysis
  • Fluid Flow
  • Fluid Mechanics
  • Froude Number
  • Laser Induced Fluorescence
  • Measurement
  • Mechanical Properties
  • Mechanics
  • Ocean Waves
  • Renewable Energy
  • Reynolds Number
  • Standing Waves
  • Three Dimensional
  • Two Dimensional
  • United States Naval Academy
  • Viscous Flow
  • Wave Power

Fields of Study

  • Physics