The Performance Prediction Of Two-Dimension Hydrofoil Based On The Finite Element Method

With the rapid development of high performance ships, the hydrofoil technology has been widely used in this area. The technical advantages of hydrofoil are relatively higher lift-drag ratio, flexible lift force controls. And to some extent, hydrofoil can reduce wave making resistance of ship. Because of these outstanding performances, hydrofoil could be used to control ship motion, reduce resistance and absorb wave energy. So it is necessary for researchers to further discuss the hydrodynamic performance of hydrofoil, the interferential effect between hydrofoil and ship hull, optimization of hydrofoil geometric parameters and so on.The summary and discussion on the numerical computation methods to tackle the flow around hydrofoil is presented in this article. Furthermore, the typical methods and their application are briefly introduced. They are finite difference method, panel method, vortex lattice method and finite element method. With the rapid development of the computer technology, the finite element method becomes an effective tool to the research and numerical computation on hydrodynamic performance of ship and hydrofoil.Based on the potential theory and the finite element method, the problem of flow around two-dimension hydrofoil is discussed in detail. The fluid region of calculation is divided into many isoparametric quadrilateral elements. According to Laplace equation, the Galerkin integral expression is derived, and the global finite element equations are solved to get the velocity potential distribution of whole flow field. In this article, two different methods are constructed and used to the calculation on the physical parameters of hydrofoils, they are the stream line control method and the velocity potential decomposition method. The 2-D hydrofoil with NACA aerofoil section is employed, and the characters of two different methods are individually discussed based on the various parameters adjustment and numerical computations. The computation process of stream line control method is easier, while the application scope of velocity potential decomposition method is broader. According to the comparison between numerical results and experiment data, perfect agreement is obtained. The validity and reliability of these methods is proven. In this paper, the numerical methods and computation codes pave the way for the further research on hydrodynamic performance of hydrofoil in viscous fluid flow with free surface.