Curtis Rusch Senior Research Engineer crusch@apl.washington.edu Phone 2066165412 
Videos
Using a Wave Energy Converter for UUV Recharge This project demonstrates the interface required to operate, dock, and wirelessly charge an uncrewed underwater vehicle with a wave energy converter. 
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11 Apr 2022


Uncrewed underwater vehicles (UUVs) predominantly use onboard batteries for energy, limiting mission duration based on the amount of stored energy that can be carried by the vehicle. Vehicle recharge requires recovery using costly, humansupported vessel operations. The ocean is full of untapped energy in the form of waves that, when converted to electrical energy by a wave energy converter (WEC), can be used locally to recharge UUVs without human intervention. In this project we designed and developed a coupled WECUUV system, with emphasis on the systems developed to interface the UUV to the WEC. 
Publications 
2000present and while at APLUW 
Effect of heave plate hydrodynamic force parameterization on a twobody wave energy converter Rusch, C.J., J. Joslin, B.D. Maurer, and B.L. Polagye, "Effect of heave plate hydrodynamic force parameterization on a twobody wave energy converter," J. Ocean Eng. Mar. Energy, 8, 355367, doi:10.1007/s4072202200236z, 2022. 
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12 Jun 2022 

Heave plates are one approach to generating the reaction force necessary to harvest energy from ocean waves. In a Morison equation description of the hydrodynamic force, the components of drag and added mass depend primarily on the heave plate oscillation. These terms may be parameterized in three ways: (1) as a single coefficient invariant across sea state, most accurate at the reference sea state, (2) coefficients dependent on the oscillation amplitude, but invariant in phase, that are most accurate for relatively small amplitude motions, and (3) coefficients dependent on both oscillation amplitude and phase, which are accurate for all oscillation amplitudes. We validate a MATLAB model for a twobody point absorber wave energy converter against field data and a dynamical model constructed in ProteusDS. We then use the MATLAB model to evaluate the effect of these parameterizations on estimates of heave plate motion, tension between the float and heave plate, and wave energy converter electrical power output. We find that power predictions using amplitudedependent coefficients differ by up to 30% from models using invariant coefficients for regular waves ranging in height from 0.5 to 1.9 m. Amplitude and phasedependent coefficients, however, yield less than a 5% change when compared with coefficients dependent on amplitude only. This suggests that amplitudedependent coefficients can be important for accurate wave energy converter modeling, but the added complexity of phasedependent coefficients yields little further benefit. We show similar, though less pronounced, trends in maximum tether tension, but note that heave plate motion has only a weak dependence on coefficient fidelity. Finally, we emphasize the importance of using experimentally derived added mass over that calculated from boundary element methods, which can lead to substantial underprediction of power output and peak tether tension. 
Influence of heave plate topology on reaction force Rusch, C.J., A.R. Hartman, B.D. Maurer, and B.L. Polagye, "Influence of heave plate topology on reaction force," Ocean Eng., 241, doi:10.1016/j.oceaneng.2021.110054, 2021. 
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1 Dec 2021 

Highlights 