Numerical analysis of hydrodynamic performance of biomimetic flapping foils based on the RANS method

This paper has investigated hydrodynamic performances of biomimetic flapping foils based on RANS method, and numerical results of aero foil profile of NACA are verified. Besides, propulsion performances of six types of biomimetic flapping foils with pure rolling motion are compared. The influence of phase difference and moving amplitude of rolling and pitching composite motion on propulsion performance is researched and the change of wake stream field is analyzed. The results showthat the hydrodynamic performance of bionic humpback whale flapping foil is better, whose average thrust in one cycle and the maximum propulsive efficiency increase with the increasing flapping frequency; the propulsion performance of rolling and pitching composite motion is superior to that of pure rolling motion, and its better values of phase difference and moving amplitude are respectively 90 degrees and 6 degrees; the leading edge vortex appears two times in one cycle, consistent with the instantaneous thrust numerical results. This method provides a reference value for the design and application of AUV.