Critical Assessment of a Transitional Delayed Detached-Eddy Simulation Model for the Prediction of the Linear Compressor Cascade V103

Abstract

The accurate prediction of transitional flows is crucial for the industrial turbomachinery design process. While RANS inherently brings conceptual weaknesses, LES will be still too expensive in the near future to affordably simulate complex turbomachinery configurations. We introduce a transitional DDES model, namely DDES-y, and analyze 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 modelled turbulent kinetic energy in the free-stream are improved when running DDES-y in combination with the synthetic turbulence generator method. Best results for DDES-y are obtained when changing the inviscid flux solver blending from dynamic to constant mode. We show that DDES-y is capable to predict the transitional flow through a linear compressor cascade, but also critically discuss the general concept and results.