A Model for Potential Deterministic Effects in Turbomachinery Flows

The unsteady interaction between blade rows due to a potential field is very important in highly loaded compressors because of its impact on operating performance. In this context the interac- tions of a flat plate wake with an upstream running pressure wave is investigated numerically using the compressible Navier-Stokes solver TRACE. Several flow conditions regarding Reynolds number, pressure wave amplitude and the axial position of the wave en- try plane are examined. The observed phenomena and dependencies are used to develop a transport model which adds determin- istic stresses by means of source terms to the sta- tionary simulation. Calculations based on the pro- posed model are described and compared with the time-accurate and steady-state numerical simulations. The model captures the influence of the unsteady ef- fects on the time-mean flow accurately and yields a speedup factor of approximately two orders of mag- nitude compared to time-accurate simulations.