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Brian Polagye

Adjunct Investigator

Assistant Professor, Mechanical Engineering





Research Interests

Tidal Energy Site and Device Characterization


Brian Polagye specializes in the characterization of tidal energy sites and devices through his work with the Northwest National Marine Renewable Energy Center. He works closely with Dr. Jim Thomson to develop instrumentation and methodologies to characterize the physical and biological environments at tidal energy sites. A combination of shipboard and stand-alone surveys monitor current velocity, turbulence, water quality, underwater noise, and marine mammal behavior. These activities are essential to the effective siting of tidal energy devices.


Connecting to the Ocean's Power: Marine Energy Research at APL-UW

The U.S. Navy's support of the University of Washington, one of the nation's preeminent research universities, leverages APL-UW capabilities with university academic expertise to address a wide range of topics in marine energy through experimentation and evaluation in laboratory settings and field deployments of prototype systems.
Companion to the technical report, APL-UW TR 2301.

5 Jul 2023

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, human-supported 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 WEC-UUV system, with emphasis on the systems developed to interface the UUV to the WEC.

Adaptable Monitoring Package — AMP

The AMP shines new light on a complex challenge: monitoring the environment around marine energy conversion sites. AMP is an adaptable sensor package that can withstand the strong currents and waves typical of such environments. Its low-cost ROV deployment system, subsea docking station, and a wet-mate connection for power and data transfer make it a flexible solution for monitoring studies.

4 Feb 2015

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2000-present and while at APL-UW

Connecting to the Ocean's Power: Marine Energy Research at APL-UW.

Bassett, C., and B. Polagye, Editors. "Connecting to the Ocean's Power: Marine Energy Research at APL-UW." Technical Report, APL-UW TR 2301. Applied Physics Laboratory, University of Washington, Seattle. April 2023, 35 pp.

5 Jul 2023

Experimental validation of float array tidal current measurements in Agate Pass, WA

Harrison, T.W., N. Clemett, B. Polagye, and J. Thomson, "Experimental validation of float array tidal current measurements in Agate Pass, WA," J. Atmos. Ocean. Technol., EOR, doi:10.1175/JTECH-D-22-0034.1, 2023.

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12 Jan 2023

Tidal currents, particularly in narrow channels, can be challenging to characterize due to high current speeds (> 1 m s-1), strong spatial gradients, and relatively short synoptic windows. To assess tidal currents in Agate Pass, WA, we cross-evaluated data products from an array of acoustically-tracked underwater floats and from acoustic Doppler current profilers (ADCPs) in both station-keeping and drifting modes. While increasingly used in basin-scale science, underwater floats have seen limited use in coastal environments. This study presents the first application of a float array towards small-scale (< 1 km), high resolution (< 5 m) measurements of mean currents in energetic tidal channel and utilizes a new prototype float, the μFloat, designed specifically for sampling in dynamic coastal waters. We show that a float array (20 floats) can provide data with similar quality to ADCPs, with measurements of horizontal velocity differing by less than 10% of nominal velocity, except during periods of low flow (0.1 m s-1). Additionally, floats provided measurements of the three dimensional temperature field, demonstrating their unique ability to simultaneously resolve in situ properties that cannot be remotely observed.

Effect of heave plate hydrodynamic force parameterization on a two-body wave energy converter

Rusch, C.J., J. Joslin, B.D. Maurer, and B.L. Polagye, "Effect of heave plate hydrodynamic force parameterization on a two-body wave energy converter," J. Ocean Eng. Mar. Energy, 8, 355-367, doi:10.1007/s40722-022-00236-z, 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 two-body 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 amplitude-dependent 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 phase-dependent coefficients, however, yield less than a 5% change when compared with coefficients dependent on amplitude only. This suggests that amplitude-dependent coefficients can be important for accurate wave energy converter modeling, but the added complexity of phase-dependent 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 under-prediction of power output and peak tether tension.

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In The News

Oscilla Power, Univ. of Wash. and others share $25M federal grant to spur wave energy efforts

GeekWire, Lisa Stiffler

The UW, in partnership with Integral Consulting, will study the underwater noise being created by wave energy converters that are being tested at the PacWave South facility on the Oregon Coast. The information will be helpful to wave energy entrepreneurs and regulating agencies working to make sure the devices don’t harm marine life.

27 Jan 2022

UW engineers test tidal energy turbines on Lake Washington

KING5 News, Laura Fattaruso

A team of engineers are testing turbines in Lake Washington that are designed to turn tides into usable energy.

17 Aug 2019

Eyes Underwater Watching Aquatic Wildlife

Environmental Monitor, Karla Lant

Recent work from researchers at the University of Washington offers a promising new way to harvest energy from waves at sea and use that energy to power an Adaptable Monitoring Package.

9 Jul 2019

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Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center