Similarity laws and model test approaches to determine hydrodynamic performance of a marine turbine

The paper presents the methodologies and approaches used in a Cavitation Tunnel or any other circulation channel to investigate the power extraction performance of a marine stream turbine. The paper first introduced model test similarity laws used in the Emerson Cavitation Tunnel (ECT) of Newcastle University to test a marine turbine in marine propeller cavitation tunnel; then based on these similarity laws to investigate the power extraction performance of a marine turbine in different approaches to control the rotation speed, namely: Torque Control and Rotation-speed control. A comparison was made by the tested experimental results. Torque Control is referred to the speed control strategy of using a generator to absorb the torque building up from the stream, on the other hand Rotation-speed control is to use motor to control rotation speed of the turbine. It indicates that both methods can be employed to investigate the hydro performance of marine stream turbine, with wider range of TSR can Rotation-speed Control test.