• Energy Research
• 2021-2025close

Re-analyzed acoustic Doppler current profiler (ADCP) data originally collected by NOAA CO-OPS (Center for Operational Oceanographic Products and Services) and equivalent point data from Pacific Northwest National Laboratory's FVCOM (Finite Volume Community Ocean Model) model of the region. Data are processed to products describing characteristics of tidal currents relevant to tidal turbines, as well as power output estimates for a notional turbine deployed from a surface platform or from the seabed at each location. These data underpin the results presented in their associated paper - see below.

Cross-flow turbines harness kinetic energy in wind or moving water. Due to their unsteady fluid dynamics, it can be difficult to predict the interplay between aspects of rotor geometry and turbine performance. This study considers the effects of three geometric parameters: the number of blades, the preset pitch angle, and the chord-to-radius ratio. The relevant fluid dynamics of cross-flow turbines are reviewed, as are prior experimental studies that have investigated these parameters in a more limited manner. Here, 223 unique experiments are conducted across an order of magnitude of diameter-based Reynolds numbers ($\approx 8\!\times\!10^4 - 8\!\times\!10^5$) in which the performance implications of these three geometric parameters are evaluated. In agreement with prior work, maximum performance is generally observed to increase with Reynolds number and decrease with blade count. The broader experimental space clarifies parametric interdependencies; for example, the optimal preset pitch angle is increasingly negative as the chord-to-radius ratio increases. As these experiments vary both the chord-to-radius ratio and blade count, the performance of different rotor geometries with the same solidity (the ratio of total blade chord to rotor circumference) can also be evaluated. Results demonstrate that while solidity can be a poor predictor of maximum performance, across all scales and tested geometries it is an excellent predictor of the tip-speed ratio corresponding to maximum performance. Overall, these results present a uniquely holistic view of relevant geometric considerations for cross-flow turbine rotor design and provide a rich dataset for validation of numerical simulations and reduced-order models. This article appeared in Hunt et al., Renewable and Sustainable Energy Reviews 206, 114848 (2024), and may be found at https://doi.org/10.1016/j.rser.2024.114848. Data supporting this manuscript may be found in the Dryad digital repository at https://doi.org/10.5061/dryad.mpg4f4r8p