DOI: 10.5061/dryad.d51c5b0dq
title: Data for: Lessons learned from the design and operation of a small-scale cross-flow tidal turbine

description: The Turbine Lander, a small-scale (1.19 m x 0.85 m) veritical-axis,
 cross-flow turbine was developed at the Applied Physics Laboratory at the
 University of Washington to generate modest amounts of power (e.g., 100 W
 average) from tidal currents. Following design and fabrication, the
 Turbine Lander was characterized in laboratory and controlled field
 testing before being deployed for 141 days in Sequim Bay, Washington.
 Cabled operations during the deployment enabled real-time data aquisition
 of variables related to system performance. In addition, environmental
 observations were sampled using an Adaptable Monitoring Package (Polagye
 at el., 2020).  "Lessons learned from the design and
 operation of a small-scale cross-flow tidal turbine" by Bassett et
 al. (2025) summarizes the efforts to characterize the system, assess its
 performance in situ, and offers lessons learned from the
 laboratory-to-field effort.  The data included here, which is
 summarized in detail below, are the outputs of key labratory and
 vessel-based characterization efforts, inflow conditions during the
 deployment, power generation by the Turbine Lander, and images of
 biofouling and optical conditions observed during the deployment. Detailed
 descriptions of the variables and example plotting scripts for working
 with the .mat files are provided.  
description: # Data from the first-generation Turbine Lander deployment
 [https://doi.org/10.5061/dryad.d51c5b0dq](https://doi.org/10.5061/dryad.d51c5b0dq) ## Description of the data and file structure Author: Christopher Bassett ([cbassett@uw.edu](mailto:cbassett@uw.edu)) Date: 30 May 2025 Description: This file contains information about the various data files supporting Bassett et al. (2025) - "Lessons learned from the design and operation of a small-scale cross-flow tidal turbine". Each of the following sections, one of the directories or .mat files. Several plotting scripts (.m) files are available for use with individual .mat files (Version 5.0). Scripts make use of datetime variables and are therefore not capability with MATLAB versions released prior to MATLAB R2014b. ### Files and variables #### File: Fouling\_and\_OpticalConditions.zip **Description:** Contains seven videos (.avi). Videos were aqcuired using the Adaptable Monitoring Package optical cameras with a 20 Hz sampling rate. Videos were post-processed and the speed was reduced to 25% of real-time acquisition. The seven videos included samples of the biofouled rotor, plant matter contributing to biofouling in the water column, and examples of variable optical clarity during operations. The video names correspond to the time (in UTC) that the first frame was aqcuired with the format (YYYY_MM_DD_hh_mm_ss) and short descriptions of what is captured by the videos. 2023_10_27_16_13_02: An example of the exceptionally poor optical clarity 2023_10_27_18_30_16: An example of the rotor operating while fouled 2023_10_27_20_12_56: An example of the rotor operating while fouled 2023_10_27_23_42_56: An example of improved optical clarity shortly after poor conditions 2023_11_04_08_26_39: An example of the rotor operating while fouled 2023_11_24_00_25_52: A large piece of kelp passes the rotor 2023_12_14_23_06_03: An example of new biofouling #### File: Dynamometer.mat **Description:** Contains process data from the dynamometer testing described in the manuscript. These calculations are described in the terminology section of the paper. ##### Variables * rpm - The speed [revolutions per minute] setpoints used in dyno testing * tor - the mean torque [N-m] applied to the drive shaft as measured by the torque cell * eta_gen - the generator efficiency * eta_tot - the total efficiency of the PTO A plotting script for this data is included in Plot_Dynamometer.m. #### File: Seal\_Loss\_Measurements.mat **Description:** Data related to the characterization of frictional losses in the Turbine Lander's power take-off based on laboratory tests. The structure "genseal" includes data from the tests performed to evaluation the parasitic losses associated with the dust seal installed on the Turbine Lander's generator. Thus, "genseal" includes motor speeds and power requirements for the unit with and without the seal installed. The structure "seal" includes data from the tests performed to evaluate the impact of all of the seals. It includes the speeds at which tests were performed (50 to 150 RPM), and the required power to drive the system under several configurations including: no external seals installed, one lip seal installed, and both lip seals and the v-seal installed. Note that the generator dust seal was installed at the time of the measurements. ##### Variables * genseal (structure) * seal (structure) * genseal.rpm - rotor speed [RPM] during tests * genseal.rsp - power [W] to drive the system with the dust seal remove * genseal.wsp - power [W] to drive the system with the seal installed * seal.rpm - rotor speed [RPM] during tests * seal.pall - power [W] to drive the system with all seals installed * seal.ponelip - power [W] to drive the system with only one lip seal installed * seal.pnoseal - power [W] to drive the system with no external seals installed A plotting script for this data is included in Plot_Dynamometer.m. #### File: TorsionalStiffness.mat **Description:**  This file contains processed data used to investigate the behavior of the magnetic coupling under load. During each test (80 total) the system was driven at a single torque applied by the prime mover while the Lander PTO was operated in constant speed mode. The system is highly stable in this configuration. Data were time averaged (torque, speed, input power) and the average encoder offset between the driveshaft and the Lander generator (on the other side of the magnetic coupling) was calculated. Note that there is a gap between input torques of approximately for negative torque values near zero. This jump corresponds to the torque application of the torque switching between being applied in the direction of rotation and against it.. The file contains a structure called 'gen' that contains four variables. ##### Variables * gen (structure) * gen.meanencoderoffset - the mean encoder offset [degrees] between the driveshaft and generator at each setpoint * gen.meantorcell - The mean torque [N-m] applied during each test * gen.meanEpow - The mean electrical power [W] driving the system during each test * gen.meanspd - The mean recorded speed [RPM] during each test A plotting script for this data is included in TorsionalStiffness.mat #### File: VesselCharacterization.mat **Description:** Results from vessel-based characterization of the rotor and PTO as described in the manuscript. The results are time averaged for all variables. The targeted vessel speeds corresponding to indices 1 to 4 in the data structures are associated with targeted inflow speeds of 2, 3, 4, and 5 knots, respectively (or roughly 1 to 2.5 m/s). Data products were calculated using measured vessel speeds. The variables include: ##### Variables * tsr: The average tip-speed ratio [dimensionless ]during each test * rpm: The average speed [RPM] during the test * tor: The average control torque [N-m] during the test * Pe: The average electrical power [W] during each test * Eff: The time-averaged water to wire efficiency during the test * C_P: The average power coefficient [dimensionless] calculated in each test A plotting script for this data is included in TorsionalStiffness.m #### File: Turbulence\_Intensity.mat **Description:** Turbulence intensity calculated in 5-minute periods. Note that this data is included including starting part way through the deployment when the ADCP was reconfigured to operate with the fifth beam. As mentioned in the manuscript, the Doppler noise removal is suspect and as a result the turbulence intensities themselves are questionable. However, from a qualitative perspective the patterns are expected to be reasonable. ##### Variables * t - datenum/time * U - Signed inflow velocity [m/s] at 3.1 m above the seabed * Iu - Turbulence intensity, multiple by 100 to get percentage Example plots #### File: Generator\_and\_Velocity.mat **Description:**  This includes ADCP data (3.1 m above the seabed) and generator operating state information. A 2-minute moving mean has been applied to all data before down sampling the data to 1-minute. Thus, all parameters represent these time-averaged quantities. Note that this includes the vast majority of the data and all of the results presented in the paper. However, the first week of data are not included as testing was ongoing and parameter changes across the instruments and Turbine Lander were common. The data include two structures: ADCP and gen, with the former referring to the acoustic Doppler current profilers and the latter holding all generator data. ##### Variables * ADCP (structure) * gen (structure) * ADCP.t - datenumber/time for the ADCP inflow measurements * ADCP.u - the "inflow" speed [m/s] measured above the rotor at 3.1 m above the seabed * gen.t - datenumbers/times for the other generator parameters * gen.Pe - Electrical power [W], negative values indicate power into the system * gen.Qc - Control torque [N-m] * gen.TSR - Tip-speed ratio [dimensionless] * gen.u - Inflow speed [m/s] passed from the AMP during operation, this does not necessarily match the post-processed ADCP data. * gen.rpm - generator speed [RPM] * gen.crpm - The commanded generator speed [RPM] based on implemented controls at the time and the inflow variable gen.u ## Access information Additional data or products available with less post-processing are available upon request. All data was derived from the tests and experiments described in the paper. No external sources of data were used.