Weinmann, M. and Sandberg, R.D.
Flow and noise predictions for a tandem cylinder configuration using novel hybrid RANS/LES approaches
At 16th CEAS/AIAA Aeroacoustics Conference, Sweden.
07 - 09 Jun 2010.
Full text not available from this repository.
The performance of several novel hybrid RANS/LES methodologies for accurate flow
and noise predictions of the NASA Tandem Cylinder Experiment are investigated. Simula-
tions are performed using three different hybrid RANS/LES methodologies which employ
different techniques to transform the baseline RANS model into a turbulence resolving
subgrid scale model. The approaches investigated are the Scale-Adaptive-Simulation which
computes the subgrid dissipation-rate from a transport equation that is sensitive to the v.
Karman length scale, the IDDES approach and a modifed Flow-Simulation-Methodology
(FSM) which both rely on replacing the modeled turbulent length scale with a measure
of the local grid spacing. Since we expect that the predictions in the RANS and LES
region depend on the capabilities of the baseline RANS model, the hybrid RANS/LES ap-
proaches used in this study are based on an Explicit-Algebraic-Stress Model. These models
are assessed and compared with formulations based on a traditional two-equation model.
The simulations are performed with the open-source finite volume code OpenFOAM and
acoustic predictions are obtained using an acoustic analogy based on Curle's theory. The
IDDES and FSM approaches were found to predict the hydrodynamic field in very good
agreement with reference data but showed some deficiencies in capturing the higher har-
monics in the acoustic spectra and broadband noise levels at high Strouhal numbers. The
SAS appraoches lack in accuracy for prediciting the hydrodynamic field but resolve the
higher harmonics in the acoustic spectra.
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