Simulation of Transient Dynamics of Shock Wave Boundary Layer Interactions Using Hybrid Large-Eddy/Reynolds-Averaged Navier-Stokes Models
Final rept. 15 Jul 2006-14 Apr 2007
NORTH CAROLINA STATE UNIV AT RALEIGH
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Simulations of the Mach 5 compression-corner shock turbulent boundary layer interaction experimentally mapped by Prof. David Dolling and co-workers have been performed using a hybrid large-eddy Reynolds-averaged Navier-Stokes LESRANS model. The model captures the mean-flow structure of the interaction reasonably well, with observed deficiencies traced to an under prediction of the displacement effects of the shock-induced separation region. The computational results provide some support for a recent theory relating to the underlying causes of low-frequency shock wave oscillation. The simulation results indicate that the sustained presence of a collection of neighboring streaks of low high momentum fluid within the boundary layer induces a low frequency undulation of the separation front. Power spectra obtained at various streamwise stations are in good agreement with experimental results, indicating that the LESRANS method is capable of predicting both the low and high-frequency dynamics of the interaction. Downstream of re-attachment, the simulations capture a three-dimensional mean flow structure, dominated by counter-rotating vortices that produce wide variations in the surface skin friction. Predictions of the structure of the re-attaching boundary layer agree well with experimental pitot pressure measurements. In comparison with Reynolds-averaged model predictions, the LESRANS model predicts more amplification of Reynolds stresses and a broadening of the Reynolds-stress distribution within the boundary layer that is probably due to re-attachment shock motion.
- Fluid Mechanics