Unsteady BEMT for fault diagnosis and prognosis in tidal stream turbines

We present the results of simulations carried out with a robust blade element momentum theory (BEMT) model. This model includes several modifications to classical BEMT, including the addition of tip/hub losses, high induction effects and, most importantly for this work, the ability to deal with arbitrary inflow conditions (i.e., including time variation and spatial non-uniformity). We use this capacity to simulate the response of tidal stream turbines (TSTs) to turbulent inflow conditions. The discussion presented centres firstly on the method of generating these inflow conditions, and secondly on how the simulation results can be used both to diagnose fault conditions during TST operation, and to prognose the fatigue lifespan of gearbox components.