Numerical Simulation Study On Characteristics Of The Single/Double Ground Effect For Bionic Wing Propeller

Propulsion by means of flapping hydrofoils which use ground effect is a method to provide thrust for autonomous underwater vehicles, which is formed based on bionics and combined with computational fluid dynamics. It has been the focus of considerable interest in the field of hydrodynamics.The practical applications designed according to the principle of ground effect are usually ground-effect aircraft, however, underwater propellers based on ground effect are sparing. Based on the theory of previous results and relevant underwater propeller design concept, this paper puts forward a new type of underwater propulsion system.In this paper, the average Renault was stokes (RANS) equation for control equation, using RNG model and the finite volume method to solve the control equations, And using second order implicit time discrete and second order the discrete format on space control equation for discrete, finally to adopt SIMPLEC algorithm to solve control coupling equations. To test the effectiveness of the program, it calculated NACA0012 airfoil hydrodynamic performance, and associated with typical test data were compared, the results show that the algorithm is correct and reliable.In the latter part of the paper, the hydrodynamic performance of six kinds of swinging foils are calculated, both the front-drive single ground effect winging and rear-drive double ground effect swinging, providing the reference for the experiments. By comparison, it is found that both in the case of single and double ground effect swinging, the mean trust coefficient and efficiency of six kinds of foils are greater than the case without ground effect; simultaneously, the mean thrust coefficient and efficiency of double ground effect swinging is higher than the single ground effcet swinging.In conclusion, this paper presents a new type of underwater propulsion, which takes both the advantages of traditional underwater propeller and ground effect into practice. And it greatly enhances the thrust; simultaneously the interaction of double foils improves the stability.