Deterministic Stress Modelling for Transonic Compressor Flows

The unsteady interaction between blade rows is very important in highly loaded compressors because of its influence on operating performance. One of the most important effects in this context is the impact of a rotor bow shock on the wake of an upstream stator blade. In order to analyze the wake-shock interactions, a generic cascade of stator blades and a transonic stator-rotor configuration are investigated numerically using time-accurate simulations. The results are compared with steady mixing-plane solutions to point out their shortcomings regarding unsteady effects and to illustrate the demands of a deterministic stress approach. A new transport model is proposed which combines the advantages of both simulation procedures, i.e. physical accuracy and computational efficiency. Deterministic stresses are added to the stationary RANS equations by means of an additional source term. After a preliminary calibration on the generic cascade, the model is applied to a real compressor configuration.