Bionic investigation of a dolphin head-based hydrofoil with emphasis on energy performance and flow characteristics

Tidal energy, regarded as clean and renewable energy source, has received widespread attention from scholars. As the basic structure of tidal power generator, the energy performance and flow characteristics of hydrofoil have a significant impact on the power generation efficiency. In this paper, a new dolphin head-based bionic hydrofoil is proposed based on the special shape of the dolphin's head, then three structures of dolphin bionic hydrofoils are obtained through corresponding modifications. Based on the accuracy verification of the numerical method, the energy performance and flow characteristics of the bionic hydrofoils are investigated. The results reveal that compared with original dolphin hydrofoil (ODH), the lift coefficients of deflected dolphin hydrofoil (DDH) under different attack angles are increased by 35.51%, 22.75%, 19.44%, 20.80%, 25.98% and 32.86%, respectively. The pressure distribution and flow characteristics around bionic hydrofoils are analyzed, and the results indicate that the pressure on the hydrofoil surface affects the lift and drag coefficients. The vortex distribution of the hydrofoil proves that DDH has a more stable flow pattern. The lift and drag coefficients is increased with the rise of inlet velocity, which provides potential value for the selection of tidal energy equipment under different application scenarios. The enhancement of the energy performance and flow characteristics prove that bionic hydrofoil will be effective in promoting energy utilization of tidal power generation and hydro turbine.