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Turbulence Modeling for Unsteady Transonic Flows

Author
Marvin, J. G.
Published
May 1980.
Physical Description
1 electronic document
Additional Creators
Seegmiller, H. L. and Levy, L. L., Jr.
Online Version

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Unclassified, Unlimited, Publicly available.
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Summary
Conditionally sampled, ensemble-averaged velocity measurements, made with a laser velocimeter, were taken in the flowfield over the rear half of an 18% thick circular arc airfoil at zero incidence tested at M = 0.76 and at a Reynolds number based on chord of 11 x 10(exp 6). Data for one cycle of periodic unsteady flow having a reduced frequency f of 0.49 are analyzed. A series of compression waves, which develop in the early stages of the cycle, strengthen and coalesce into a strong shock wave that moves toward the airfoil leading edge. A thick shear layer forms downstream of the shock wave. The kinetic energy and shear stresses increase dramatically, reach a maximum when dissipation and diffusion of the turbulence exceed production, and then decrease substantially. The response lime of the turbulence to the changes brought about by the shock-wave passage upstream depends on the shock-wave strength and position in the boundary layer. The cycle completes itself when the shock wave passes the midchord, weakens, and the shear layer collapses. Remarkably good comparisons are found with computations that employ the time-dependent Reynolds averaged form of the Navier-Stokes equations using an algebraic eddy viscosity model, developed for steady flows.
Other Subject(s)
Collection
NASA Technical Reports Server (NTRS) Collection.
Note
Document ID: 19980213316.
NASA/TM-1979-208062.
NAS 1.15:208062.
AIAA Paper 79-0071.
AIAA Journal; Volume 18; No. 5; 489-496.
Aerospace Sciences; 15-17 Jan. 1979; New Orleans, LA; United States.
Terms of Use and Reproduction
No Copyright.
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