Based On Unstructured Grid Superb Sound Velocity Flow Field Calculation Method

In this thesis, some algorithms on unstructured triangular grids are presented for solving the Euler equations, especially for solving the hypersonic problems.On the base of unstructured grid generating program, The self-adaptive mesh technique is employed to improve the efficiency and accuracy of the calculation, and can preserve the mesh' s quality. The cell-centred finite volume algorithm, NND finite volume algorithm and AUSM+ finite volume algorithm are studied for solving the Euler equations, their abilities for hypersonic problem are studied especially. Through the paper' s study, The cell-centred finite volume algorithm and the 2-order AUSM+ finite volume algorithm can solve the subsonic flow problem well; the NND finite volume algorithm and 2-order AUSM+ finite volume algorithm can solve the hypersonic flow problem well. But the NND algorithm can' t reach 2-order precision, and the cell-centred finite volume algorithm is not suit to solve hypersonic problem.For the efficiency of the four-stage Runge-kutta time- stepping scheme is low, and the robust is bad for the hypersonic problem, an implicit time-stepping scheme is adopted. This scheme can preserve the results precision and improve the computing efficiency sharply, and is an innovation for the time-stepping scheme of unstructured grid.In this paper, some flows around NACA 0012 aerofoil, M6 wing and two different blunt vehicles are simulated, the results show that the present algorithm possesses good characteristics and capability for normal MACH number and for hypersonic of simple configurations .