NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Computation of Separated and Unsteady Flows with One- and Two-Equation Turbulence ModelsThe ability of one- and two-equation turbulence models to predict unsteady separated flows over airfoils is evaluated. An implicit, factorized, upwind-biased numerical scheme is used for the integration of the compressible, Reynolds averaged Navier-Stokes equations. The turbulent eddy viscosity is obtained from the computed mean flowfield by integration of the turbulent field equations. The two-equation turbulence models are discretized in space with an upwind-biased, second order accurate total variation diminishing scheme. One and two-equation turbulence models are first tested for a separated airfoil flow at fixed angle of incidence. The same models are then applied to compute the unsteady flowfields about airfoils undergoing oscillatory motion at low subsonic Mach numbers. Experimental cases where the flow has been tripped at the leading edge and where natural transition was allowed to occur naturally are considered. The more recently developed field-equation turbulence models capture the physics of unsteady separated flow significantly better than the standard kappa-epsilon and kappa-omega models. However, certain differences in the hysteresis effects are obtained. For an untripped high-Reynolds-number flow, it was found necessary to take into account the leading edge transitional flow region in order to capture the correct physical mechanism that leads to dynamic stall.
Document ID
19970001720
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Ekaterinaris, John A. (NASA Ames Research Center Moffett Field, CA United States)
Menter, Florian R. (NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1994
Publication Information
Publisher: American Inst. of Aeronautics and Astronautics
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
NAS 1.15:111799
NASA-TM-111799
AIAA Paper 94-0190
Meeting Information
Meeting: Aerospace Sciences Meeting and Exhibit
Location: Reno, NV
Country: United States
Start Date: January 10, 1994
End Date: January 13, 1994
Sponsors: American Inst. of Aeronautics and Astronautics
Accession Number
97N11494
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available