Numerical prediction of hydrodynamic performance of differently shaped flapping foil propulsors

  Objectives  The hydrodynamic performance of three-dimensional hydrofoils with different shapes is studied in order to find the optimal hydrofoil geometry.

  Methods   NACA 0012 hydrofoil model with different aspect ratios, tip ratios, forward-swept and back-swept shapes are used to simulated the flow field of the hydrofoil with multi-DOF coupling motion based on the NUMECA Fine/Marine solver. The reliability of the numerical method is validated by comparison with the experimental results and analysis of grid independence.

  Results  The results show that a hydrofoil with a larger aspect ratio has better performance. By comparing the results of hydrofoils with the same aspect ratio and different tip ratios, it is found that tip ratio causes performance degradation. By comparing the results of forward-swept, back-swept and trapezoidal hydrofoils with the same tip ratio, it is found that the performance of the back-swept hydrofoil is optimal, and the shape of the trailing edge has great influence on hydrofoil performance.

  Conclusions  This study obtains certain optimal geometrical parameters of flapping foil propulsors, and achieves greater understanding of the characteristics of wake vortex structures.