Comparison of Wind Tunnel and Flight Test Afterbody and Nozzle Pressures for a Twin-Jet Fiqhter Aircraft at Transonic Speeds
Nugent, Jack and Pendergraft Jr., Odis C. (1987) Comparison of Wind Tunnel and Flight Test Afterbody and Nozzle Pressures for a Twin-Jet Fiqhter Aircraft at Transonic Speeds. Technical Report NASA TP-2588, Research Engineering, NASA Dryden Flight Research Center.
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Abstract
Afterbody and nozzle pressures measured on a 1/12-scale model and in flight on a twin-jet fighter aircraft were compared as Mach number varied from 0.6 to 1.2, Reynolds number varied from 17.5 million to 302.5 million , and angle of attack varied from 1 degree to 7 degrees.
At Mach 0.6 and 0.8, nozzle pressure coefficient distributions and nozzle axial force coefficients agreed and showed good recompression.
At Mach 0.9 and 1.2, flow complexity caused a loss in recompression for both flight and wind tunnel nozzle data . The flight data exhibited less negative values of pressure coefficient and lower axial force coeffcients than did the wind tunnel data. Reynolds number effects were noted only at these Mach numbers. Jet temperature and mass flux ratio did not affect the comparisons of nozzle axial force coefficient.
At subsonic speeds, the levels of pressure coefficient distributions on the upper fuselage and lower nacelle surfaces for flight were less negative than those for the model.
The model boundary layer thickness at the aft rake station exceeded that for the forward rake station and increased with increasing angle of attack . The flight boundary layer thickness at the aft rake station was less than that for the forward rake station and decreased with increasing angle of attack.
| EPrint Type: | NASA Technical Publication |
|---|---|
| Keywords: | Nozzle-afterbody flow interactions, Reynolds number effects, Wind tunnel and flight comparison |
| Subjects: | (01 - 09) Aeronautics: (02) Aerodynamics |
| ID Code: | 491 |
| Deposited On: | 11 January 2006 |
| Additional Information: | 125 pages. Odis C. Pendergraft, Jr. , is affiliated with NASA Langley Research Center, Hampton, Virginia. |
