Flat Drag Reduction Method Based on Biomimetic Fish-body Structure

Ocean environments are complex, wherein the variation in flow velocity is wide and the general drag reduction mode with robots is unstable. In this study, a new drag reduction method is proposed for robots to better adapt to ocean environments. The effect of drag reduction is verified by numerical simulations and experiments. First, based on the principle of bionics, a robot fish operating under a body and/or caudal fin(BCF) mode is selected as the research object, and the model is reconstructed to duplicate the fish body. Second, the effects of model length, height, and thickness on drag reduction are studied by numerical simulation. The law of drag reduction is also summarized, and the mechanism of drag reduction is investigated intensively. The correctness of the numerical simulation is verified through a fluid experiment. Experimental results show that with an increase in the model length, the effect of drag reduction is gradually worsened. However, the flow velocity that preforms the best drag reduction effect is not affected by the length. The effect of drag reduction is greatly affected by the change in model height. With an increase in model thickness, the range of flow velocity that preforms drag reduction increases. The reconstructed model effectively reduces drag and has a wide range of flow velocity applications, thus enabling better adaptation to ocean environments