Hydrodynamic analysis of submersible propulsion system imitating tuna-tail

In this paper, the unsteady hydrodynamic characteristics of oscillating tuna tail are analyzed numerically by surface panel method. The tuna tail is considered as a three dimensional lunate fin oscillating with the mode combined swaying and yawing in uniform flow. The low order potential based surface panel method using the hyperboloidal quadrilateral panels is applied to solve numerically the unsteady flow. On the trailing edge of the fin the pressure Kutta condition is satisfied. The thrust coefficient, the lateral force coefficient and the propulsion efficiency can be obtained. The effects of the oscillating amplitude and the phase difference between swaying and yawing are investigated. The analytical result indicates that the present numerical method is effective for researching into the hydrodynamic characteristics of oscillating tuna tail.