Development and Validation of Navier-Stokes Procedure for Turbomachinery Unsteady Flow

Abstract

An unsteady viscous e ow solver based on the Runge ‐Kutta scheme has been developed. Three low-Reynoldsnumber k- turbulence models have been assessed for their ability to predict unsteady transitional e ow. The k- model has been modie ed to incorporate leading-edge effects. A pseudo time approach has been used to accelerate the numerical algorithm for unsteady e ows. A sensitivity study has been carried out, including the effects of the artie cial dissipation, the grid density, and the physical and pseudo time steps. The numerical simulation of the unsteady transitional e ow in a compressor cascade has been carried out successfully. Good agreement with the measured data as well as the previous Euler/boundary-layer predictions has been achieved. The numerical solver has been ableto predict major features, associated with the wake-induced transition on a compressorblade (wakeinduced transitional strip, wake-induced turbulent strip, etc. ). An analysis and an interpretation of the results from the unsteady e ow simulation have been carried out to understand additional e ow physics associated with the transitional e ow.