Turbulence Characterization in Compressor Tandem Blades Aerodynamics

Numerical simulations of a subsonic tandem com-
pressor blade cascade (Re_c = 3 × 105 , M_i = 0.6)
are carried out using wall-resolved implicit LES with a
high-order discontinuous Galerkin method and RANS
(SST and transitional SST − γ − Reθ ) with a finite-
volume method. The wrLES serves as a high-fidelity
reference for assessing RANS performance.
The isentropic Mach number on the blade surface
and the total pressure losses in the wake are compared
between wrLES and RANS. The transitional model
captures qualitatively separation on the suction side of
the front blade and the pressure side of the rear blade
but fails to reproduce the unsteady wake–boundary-
layer interaction on the suction side of the rear blade,
predicting laminar separation and reattachment in-
stead. In contrast, the standard SST model does not
capture separation at all. In terms of losses, wrLES re-
veals an asymmetric two-humped profile with higher
pressure-side losses in the wake, whereas RANS pro-
duces quasi-symmetric distributions.
Barycentric anisotropy analysis shows RANS solu-
tions confined to the plane-strain line, while LES ex-
poses richer turbulence states. Using SU2’s EQUiPS,
we quantify turbulence-model uncertainty on wake
losses. The predicted band encloses most of the LES
distribution, except at the pressure-side peak. This un-
derscores the need for improved closures and the util-
ity of uncertainty quantification for such applications.