RealTide Deliverables: D3.5 Report on Synthetic Load Spectra and Time Series

This report describes Deliverable 3.5 and details the work of Task 3.5 within WP3 of RealTide. As the main objective of the task requires a non-dimensional load spectra and time series dataset to assist future developers in tidal stream turbine design decisions, datasets available from different test setups have been collected and categorized. Based on the information available from these tests, 21 non-dimensional coefficients are proposed to make these test measurements independent from their turbine designs and flow conditions. The proposed non-dimensional variables take information both from the input measurements as well as internal forces calculated in this analysis based on static equilibrium linear equations, thus common test data, such as thrust and torque, are used to make this easily applicable for future tests. The load spectra and time series have been developed in relation to the tip speed ratio (TSR) of 10 tank tests. These normalized base datasets have successfully been correlated when compared to different datasets from both numerical models and commercial tests. All the non-dimensional coefficients and ratios are presented in both the time domain and the frequency domain for developers to not only consider static load cases but also dynamic loads that impact the fatigue life of the different key components of tidal turbines. The density distribution curves as well as the frequency spectra of these coefficients can be recreated with the produced datasets of this task, which have been stored in the Edinburgh DataShare portal.