Performance Investigation of a Humpback Whale-Inspired Vertical Axis Current Turbine

Abstract

Efficiency and self-starting capability performances are the main problems in vertical axis current turbines (VACT). By purposing improves its performance, VACT has been developed with various models. One development of this model is designing the turbine blade into a bio-inspired shape. The fluke and flipper of a humpback whale become an inspiration to design the VACT blade. This study aims to investigate the ability of a humpback whale-inspired turbine (HWIT) in terms of efficiency, symbolized by power coefficient (CP), and self-starting capability, symbolized by static torque coefficient (CTs). HWIT turbine was designed by applying an extremities chord ratio (Λ), determined from the ratio between the upper and lower part of the humpback whale fluke. Moreover, NACA 634021 foil, inspired by a humpback whale flipper, was used to create the main blade form of an HWIT. NACA 0018, another foil profile used as the main foil from the previous study, was applied as a comparator to NACA 634021 foil. The simulation results using the QBlade software show that NACA 634021 has an excellent agreement validation with the previous study, both numerically and experimentally. The results present that the optimal blade shape of HWIT is reached at Λ = 0.5. Also, HWIT using NACA 634021 has higher efficiency of 0.335 and reaches self-starting capability at λmin = 2.2 compared to HWIT using NACA 0018.