Investigation in wave number of rajiform swimmers

Rajiform-type fish swim under water with two pectoral fins. A bionic rajiform model inspired by the fish of this type is developed in this paper. The bionic model mimics the movement of rajiform swimmers using dynamic mesh technique in Fluent, and then the effects of wave number on the propulsion performance are analyzed. Simulation results show that bionic model can achieve the maximum propulsion efficiency with wave number of 0.75 under steady-state motion cycles. The optimal wave number on bionic model is coherent with that on natural rajiform fish which have experienced thousands of years´ natural evolution.