Experimental tests and CFD simulations of a horizontal wave flow turbine under the joint waves and currents

Abstract This paper focus on the comparison of traditional vertical-axis turbines and a newly proposed horizontal wave flow turbine. Firstly, the major design parameters of this new concept are presented. Then a series of experimental tests of a prototype in the towing tank have been performed to investigate its hydrodynamic performance. It is found that the highest energy conversion rate is about 24.83% and the average impeller rotation power also reaches its maximum value of 352 W among all the six design cases. In addition, the Computational Fluid Dynamics (CFD) simulations have been performed to investigate its hydrodynamic characteristics and energy harvesting efficiency under the combined action of waves and currents. The results also show that the amplitude of the turbine's thrust and torque moment fluctuations increase with increasing motion amplitude. Furthermore, the wave dynamics cause instantaneous fluctuations in the flow field distribution for both types and the horizontal wave flow turbine has a more stable flow field. The comparison of both types of turbine based on the CFD simulations show that the torque moment, thrust force, and lateral force coefficients of the horizontal wave flow turbine are approximately 1.2–1.5 greater than those of the vertical axis turbine. Therefore, the horizontal wave flow turbine shows better energy harvesting efficiency if compared with the traditional vertical one.