Horizontal axis tidal stream turbines operate in a challenging marine environment, characterised by highly unsteady, turbulent flow, significant velocity shear and wave loading. The resulting dynamic blade loads are expected to be a limiting factor on the turbine performance and operational limits, but unsteady performance data for thicker aerofoil sections is not readily available and the blade design process only considers steady flows. The potential for blade surface biofouling complicates this issue further, particularly due to likely performance degradation during the device lifecycle.

Static and oscillatory wind tunnel tests have been conducted, including both clean and roughened blade sections to quantify the change in dynamic performance as a result of lifecycle fouling. Findings from this investigation will be presented highlighting the underlying fluid mechanisms and behaviour, dynamic flow modelling approaches, and their impact on tidal turbine design and

Keywords: Applied fluid dynamics, Aerodynamics