Vortex Dynamics Principles of Direction Control, Speed Control and Energy-saving Mechanism of Self-propelled Swimming of Fish School

Vortex dynamics principles of direction control, speed control and energy saving of fish school are investigated in this paper. It is found that the vortex dynamics principle of direction control is to generate vortices in favor of turning and preventing the harmful separation from the head. The vortex dynamics principle of speed control of fish school is that the merger of vortices with the same sign can speed up the fish. The vortex dynamics principle of energy saving of the swimming of a. fish school is that when using the favorable vortical wake in front or by the side, the flapping frequency of the fish can be reduced up to 18.35%, therefore save energy.