Relaxation Solution for the Transonic Flow Through a Cascade
The finite difference relaxation method is developped to calculate the performances of the cascade up to transonic range with occurring of shocks. The full potential equation with exact boundary conditions is solved in a conformal coordinate system constitued by the stream function and the potential function of the incompressible flow through the same cascade. The grid points on the boundary of the computational region are established after resolving the incompressible flow by the singularities method whereas the internal grid points are determined by means of the finite difference technic. The transonic potential field is computed using Jameson’s rotated upwind difference scheme in the supersonic region, and central difference scheme in the subsonic region. Thus in the supersonic regions, the disturbances are propagated from upstream to downstream; and terms provided from the truncation error acting as the artificial viscosity are introduced into the governing equation, making the occurring of the shocks automatically during the iterative process. Examples applied to cascades of compressor and turbine are also given.
KeywordsEntropy Vortex Controled
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