Model validation of hydrodynamic loads and performance of a full-scale tidal turbine using Tidal Bladed

Abstract

This paper presents a comparison of predicted and measured performance and loading for the Alstom Ocean Energy’s 1 MW tidal turbine, DEEP-Gen IV, which was deployed at the European Marine Energy Centre (EMEC) in Orkney as part of the ReDAPT (Reliable Data Acquisition Platform for Tidal) project. The ReDAPT project was commissioned and co-funded by the Energy Technologies Institute.

Unsteady time domain simulations are conducted using DNV GL’s Tidal Bladed software. The hydrodynamic loads are computed using a blade-element formulation that accounts for flow blockage. The onset flow turbulence is described using a von Kármán velocity spectra and coherence functions. Length scales are determined from a site characterisation study using field measurements.

Machine data is processed and quality control filters applied to obtain measurement ensembles suitable for comparison with simulation outputs. Comparisons are made for electrical power, pitch angle and blade near-root bending moment. Good agreement is found between the simulated and measured flapwise near root-bending damage equivalent loads and load spectra. The stochastic blade load data is further analysed where it is found that the methodologies applied provide accurate predictions of machine fatigue loads due to turbulence.