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The lagRST Model: A Turbulence Model for Non-Equilibrium FlowsThis study presents a new class of turbulence model designed for wall bounded, high Reynolds number flows with separation. The model addresses deficiencies seen in the modeling of nonequilibrium turbulent flows. These flows generally have variable adverse pressure gradients which cause the turbulent quantities to react at a finite rate to changes in the mean flow quantities. This "lag" in the response of the turbulent quantities can t be modeled by most standard turbulence models, which are designed to model equilibrium turbulent boundary layers. The model presented uses a standard 2-equation model as the baseline for turbulent equilibrium calculations, but adds transport equations to account directly for non-equilibrium effects in the Reynolds Stress Tensor (RST) that are seen in large pressure gradients involving shock waves and separation. Comparisons are made to several standard turbulence modeling validation cases, including an incompressible boundary layer (both neutral and adverse pressure gradients), an incompressible mixing layer and a transonic bump flow. In addition, a hypersonic Shock Wave Turbulent Boundary Layer Interaction with separation is assessed along with a transonic capsule flow. Results show a substantial improvement over the baseline models for transonic separated flows. The results are mixed for the SWTBLI flows assessed. Separation predictions are not as good as the baseline models, but the over prediction of the peak heat flux downstream of the reattachment shock that plagues many models is reduced.
Document ID
20110024207
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Lillard, Randolph P. (NASA Johnson Space Center Houston, TX, United States)
Oliver, A. Brandon (NASA Johnson Space Center Houston, TX, United States)
Olsen, Michael E. (NASA Ames Research Center Moffett Field, CA, United States)
Blaisdell, Gregory A. (Purdue Univ. West Lafayette, IN, United States)
Lyrintzis, Anastasios S. (Purdue Univ. West Lafayette, IN, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2011
Subject Category
Aerodynamics
Report/Patent Number
JSC-CN-25446
Meeting Information
Meeting: 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition
Location: Nashville, TN
Country: United States
Start Date: January 9, 2012
End Date: January 12, 2012
Sponsors: American Inst. of Aeronautics and Astronautics
Distribution Limits
Public
Copyright
Public Use Permitted.

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