Small Darrieus hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Efficiency improves as size increases, since adequate blade chord Reynolds numbers...

Darrieus type hydrokinetic turbines (HKTs) with fixed pitch blades, like their wind turbine equivalents, exhibit poor starting torque whether blades are straight, troposkein or helical. High solidity improves starting torque to some extent but reduces peak efficiency. Straight blade turbines...