Reduction of tidal turbines hydrodynamic loads employing bend-twist adaptive blades

Abstract

The present paper is one of the first to investigate the use of bend-twist adaptive blades on a variable-speed pitch-controlled tidal turbine in order to reduce hydrodynamic loads. The realisation of the substantial unexploited hydrokinetic energy of tides is currently driving hydrokinetic turbine research. In contrast to wind turbines, tidal technology has not yet reached maturity and new designs are required in order to take into account cavitation, leading edge roughness, and the high energy density of flowing water. In particular, reinforced blade structures are required to deal with the high hydrodynamic loads experienced by tidal turbines. In this research, the potential benefit of using bend-twist adaptive blades on tidal turbines in order to reduce hydrodynamic loads is explored. A Tidal Turbine Hydrodynamic code (TTHydro) capable of simulating tidal turbines equipped with adaptive blades is developed and validated. It is found that employing bend-twist adaptive blades on variable-speed pitch-controlled tidal turbines reduces both power and loads. It was also observed that a substantial reduction of hydrodynamic loads could be achieved at the price of a small power loss.