Propulsive Performance of Bionic Underwater Vehicle Based on Four Flexible Oscillating Foils: A Numerical Investigation

A conceptual design of a bionic UUV was proposed, with two pairs of bio-inspired hydro foil undergoing travelling wavy motion. In addition, three types of motion strategies are designed. In Mode A, the foils 1^# and 3^# undergo flexible motion. In Mode B, the foils 1^# and 3^# remain stationary while the others undergo motion. In Mode C, all four foils are in consistent flexible motion. The propulsive performance of the current bionic UUV under above three motion types is numerically investigated by solving the incompressible viscous Navier–Stokes equations coupled with the dynamic grid method. The simulation results reveal that the motion type of Mode C exhibits the best propulsive performance with respect to high propulsive efficiency (= 74.5%) and large thrust force coefficient (= 4.83). Moreover, typical vortex structures in the wake of the bionic UUV are also presented and analyzed, the results of which demonstrate that there exists close connection between the vortex distribution and propulsive property.