Hydrodynamic analysis of a mechanical pectoral fin in unsteady flow

Two degrees of freedom (DoF) and three DoF motion models were established for a rigid pectoral fin. Through the secondary development of FLUENT CFD software, which was based on Reynolds-Averaged Navier-Stokes equations, the dynamic mesh methods and post-processing systems of the FLUENT software were used to calculate thrust characteristics of the mechanical pectoral fin. The RNG k-Ε model was adopted for fully developed turbulent flow, and the wall function method was adopted for flow near a wall. In order to overcome numerical instability for high Reynolds number flows, the quadratic upwind scheme (QUICK) was used. Numerical results were compared with recent experimental results. After comparing the computed results with the results gained from experiments and from the vortex lattice method, we analyzed and showed that it is feasible to solve the problem using FLUENT software.