Effects of Bionic Bone Flexibility on the Hydrodynamics of Pectoral Fins

Compared with traditional underwater equipment powered by propeller, the manta-ray-inspired vehicle MPF mode (Median fin/paired fin) has advantages of stable swimming attitude, high maneuverability, and low noise, etc. As one sources advancing power when swims, flexible deformation pectoral fin is an important factor affecting hydrodynamic performance. In this paper, a mechanical analysis two-dimensional using thin wing theory shows that main force level curvature chordal section. By designing two-stage bionic skeleton at leading rear edges vehicle, root–tip section width used to characterize fin’s flexibility, tensiometer quantitatively measure flexibility. The root-to-tip ratio cross-section was varied obtain different levels properties fins during flapping were measured sensor normalized for analysis. experimental results show reduction flexibility edge increase are beneficial improvement thrust performance, same as distribution skeletal in real organisms. Fitting curves fins’ relative thrust/lift significant effect on its force, stiffer softer can improve characteristics vehicle. Phase differences interacting also enhance dynamic within 10~30 degree.