Experimental study on hydrodynamic characteristics of flexible flapping foil

To investigate the influence of flapping foils'stiffness and motion parameters on its hydrodynamic characteristics, relying on the bionic flapping foil propulsion test platform, the combination of pitching motion and heaving motion of the foils was realized. A six-axis force/moment sensor was used to record the mechanical parameters during the motion, and a high-speed camera was used to record the motion. The mechanical data were homogenized and normalized to obtain the variation law of the hydrodynamic characteristics of the foils with stiffness and motion parameters. The images were also processed to plot the motion trajectory of the tail end point of the foil. Experimental results show that the low stiffness flapping foil has excellent thrust performance at low frequencies;a foil's stiffness plays an essential role in thrust stability, and the motion trajectory of flap foil changes from haphazard to a figure 8 shape and eventually into an arc as the stiffness increases. © 2022, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.