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Turbulence modeling for unsteady transonic flows
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Marvin, J. G. Seegmiller, H. L. Levy Jr., L. L. |
| Copyright Year | 1980 |
| Description | 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. |
| File Size | 786451 |
| Page Count | 9 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19980213316 |
| Archival Resource Key | ark:/13960/t77t2hc9d |
| Language | English |
| Publisher Date | 1980-05-01 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Heat Transfer Transonic Flow Laser Doppler Velocimeters Compression Waves Airfoils Unsteady Flow Navier-stokes Equation Calcium Oxides Turbulence Models Flow Distribution Reynolds Averaging Shear Stress Mathematical Models Velocity Measurement Kinetic Energy Boundary Layers Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
