Experimental and numerical study on hydrodynamics of swimming paddle for a shoal crab robot

The rigid swimming paddle as an auxiliary motive power underwater is modeled and designed as the first attempt for the shoal crab robot Crabot-I. In this work, the hydrodynamics of a swimming paddle is investigated numerically and experimentally. The primary focus of our study is related specifically to the effect of St on hydrodynamic performance of a single swimming paddle in lift-based and drag-based modes, and the load-generating mechanism by studying the relations among evolution of vortex, pressure distribution and load characteristics, as well as demonstration and validation in low-speed tunnel. The results of numerical calculations by CFD and tests in the Ship Maneuverability Laboratory (HEU) Water Tunnel are both used to demonstrate fundamental properties of swimming paddle, and to provide a reference for the further research on subsea swimming gait based on the synergetic motion of two paddles.