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Crossflow-vortex breakdown on swept wings: correlation of nonlinear physics
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Joslin, R. D. Streett, C. L. |
| Copyright Year | 1994 |
| Description | The spatial evolution of cross flow-vortex packets in a laminar boundary layer on a swept wing are computed by the direct numerical simulation of the incompressible Navier- Stokes equations. A wall-normal velocity distribution of steady suction and blowing at the wing surface is used to generate a strip of equally spaced and periodic disturbances along the span. Three simulations are conducted to study the effect of initial amplitude on the disturbance evolution, to determine the role of traveling cross ow modes in transition, and to devise a correlation function to guide theories of transition prediction. In each simulation, the vortex packets first enter a chordwise region of linear independent growth, then, the individual packets coalesce downstream and interact with adjacent packets, and, finally, the vortex packets nonlinearly interact to generate inflectional velocity profiles. As the initial amplitude of the disturbance is increased, the length of the evolution to breakdown decreases. For this pressure gradient, stationary modes dominate the disturbance evolution. A two-coeffcient function was devised to correlate the simulation results. The coefficients, combined with a single simulation result, provide sufficient information to generate the evolution pattern for disturbances of any initial amplitude. |
| File Size | 439029 |
| Page Count | 29 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20040111998 |
| Archival Resource Key | ark:/13960/t3dz55r0t |
| Language | English |
| Publisher Date | 1994-01-01 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Thermodynamics Navier-stokes Equation Incompressible Flow Swept Wings Direct Numerical Simulation Nonlinearity Vortex Breakdown Velocity Distribution Cross Flow Pressure Gradients Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
