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Delay of turbulent boundary layer detachment by mechanical excitation: application to rearward-facing ramp
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | McKinzie Jr., Daniel J. |
| Copyright Year | 1996 |
| Description | A vane oscillating about a fixed point at the inlet to a two-dimensional 20 deg rearward-facing ramp proved effective in delaying the detachment of a turbulent boundary layer. Flow-field, surface static pressure, and smoke-wire flow visualization measurements were made. Surface pressure coefficient distributions revealed that two different effects occurred with axial distance along the ramp surface. The surface pressure coefficient varied as a complex function of the vane oscillation frequency and its trailing edge displacement amplitude; that is, it varied as a function of the vane oscillation frequency throughout the entire range of frequencies covered during the test, but it varied over only a limited range of the trailing edge displacement amplitudes covered.The complexity of these findings prompted a detailed investigation, the results of which revealed a combination of phenomena that explain qualitatively how the mechanically generated, periodic, sinusoidal perturbing signal produced by the oscillating vane reacts with the fluid flow to delay the detachment of a turbulent boundary layer experiencing transitory detachment. |
| File Size | 65712599 |
| Page Count | 75 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19960029324 |
| Archival Resource Key | ark:/13960/t0vq7vx59 |
| Language | English |
| Publisher Date | 1996-03-01 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Heat Transfer Static Pressure Pressure Effects Hot-wire Anemometers Pressure Distribution Turbulent Boundary Layer Oscillations Velocity Distribution Boundary Layer Separation Detachment Flow Distribution Vanes Wind Tunnel Tests Surface Properties Flow Visualization Boundary Layer Transition Diffusers Pressure Measurement Backward Facing Steps Frequency Ranges 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 |
