In-Situ Blade Strain Measurements of a Crossflow Turbine Operating in a Tidal Flow

This data was collected between October 25 and December 12 of 2022 at the University of New Hampshire (UNH) and Atlantic Marine Energy Center (AMEC) turbine deployment platform (TDP). The priority of this measurement campaign was to collect blade strain data from a crossflow turbine operating in a tidal flow. Along with the submitted data is a table ('Deployment_schedule.PNG) that outlines the various dates when each instrument was operational. This data was analyzed and used to produce a manuscript submitted to Renewable Energy (Bichanich et al 2024).

All data contained in this submission is unfiltered/unprocessed data unless otherwise noted in the README file.

The TDP is a floating structure moored on the Portsmouth facing side of Memorial Bridge pier #2, which spans the Piscataqua River between Portsmouth, NH and Kittery, ME. The Piscataqua River connects the Great Bay Estuary to the Gulf of Maine and the river currents are dominated by tidal flow with water velocities exceeding 2.5 m/s during spring ebb tides at this site which were previously characterized by Chancey 2019.

The turbine under test was a modified New Energy Corporation (Calgary, CA) model EVG-025 4-blade H-Darrius type vertical axis cross flow turbine that rotates in the clockwise direction with a rotor diameter of 3.2m and blade length of 1.7m. The hydro-foil profile was a NACA 0021 with a 10 inch chord length and a blade preset pitch angle of +4deg with a positive angle corresponding with the toe in direction. The standard EVG-025 has a rotor diameter of 3.4m and its rated power output is 25kW at 3 m/s. The rotor diameter was reduced to accommodate the size of the existing TDP moon-pool. A single blade of this turbine was further modified to accommodate 8 full-bridge strain gauges (Bharath et al 2023, Bichanich et al 2024). For power performance and other relevant details on the turbine and its characteristics, see O'Byrne 2022.

Blade strain was measured using 8 foil-based strain gauges along the span of a single turbine blade. Water currents were measured using Acoustic Doppler Current Profilers (ADCP's) and Acoustic Doppler Velocimeters (ADV's) both upstream and downstream of the turbine for inflow, wake and turbulence measurements. Electrical power output was measured using the Voltsys rectifier. Shaft speed was calculated based on the Voltsys measurements of the permanent magnet three phase generator AC generation frequency, coupled directly to the cross flow turbine under test (i.e., no gear box). Platform motions were captured using a Yost IMU (inertial measurement unit). Turbine thrust loading was measured using a reaction arm about the turbine deployment platform spanning beam, where two bi-directional load cells were connected to the system via a pinned connection.

This submission includes zipped folders for each instrument containing data in .csv files for the relevant duration specific to each instrument, along with separate README file for each measurement. Some instrument files are quite large and can pose a challenge for a visual spreadsheet editor to open. A processing software like MATLAB or Python is recommended.

For more information on this measurement campaign, please see:

Bichanich et al. "In-Situ Blade Strain Measurements and Fatigue Analysis of a Crossflow Turbine Operating in a Tidal Flow," Renewable Energy. 2024.

Kaelin Chancey. "Assessment Of The Localized Flow And Tidal Energy Conversion System At An Estuarine Bridge," University of New Hampshire Master's Thesis 2019

Bharath et al. "OPEN WATER BLADE STRAIN MEASUREMENTS ON A VERTICAL-AXIS TIDAL TURBINE," Proceedings of the ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. June 11-16, 2023.

Patrick O'Byrne. "Concurrent Measurements of Inflow, Power Performance and Loads for a Grid-Synchronized Cross-Flow Turbine Operating in a Tidal Estuary", University of New Hampshire Master's Thesis. 2022.