Transitional Delayed Detached-Eddy Simulation for a Compressor Cascade: A Critical Assessment

Abstract

The accurate prediction of transitional flows is crucial for the industrial turbomachinery design process. While a Reynolds-averaged Navier–Stokes approach inherently brings conceptual weaknesses, large-eddy simulation will still be too expensive in the near future to affordably analyze complex turbomachinery configurations. We introduce a transitional delayed detached-eddy simulation (DDES) model, namely, DDES-\gamma, and analyze the numerical results of the compressor cascade V103. A comparison with the fully turbulent DDES approach emphasizes the benefit of coupling DDES with a transition model. Issues with undesired decay of modeled turbulent kinetic energy in the freestream are improved when running DDES-\gamma in combination with the synthetic turbulence generator method. The best results for DDES-\gamma are obtained when changing the inviscid flux solver blending from dynamic to constant mode. We show that DDES-\gamma is capable of predicting the transitional flow through a linear compressor cascade, but we also critically discuss the general concept and results.