Accession Number:

ADA564004

Title:

Flight Experiments on Swept-Wing Roughness Receptivity: Validation Data for Modeling and Computations

Descriptive Note:

Final rept. 1 Jun 2008-31 Dec 2009

Corporate Author:

TEXAS A AND M UNIV COLLEGE STATION DEPT OF AEROSPACE ENGINEERING

Personal Author(s):

• Saric, William S.

Report Date:

2010-09-22

Pagination or Media Count:

33.0

Abstract:

Micron-sized, spanwise-periodic Discrete Roughness Elements DREs were applied to the leading edge of a 30-degree swept-wing. The test article was attached vertically to the port wing of a Cessna O-2A aircraft and operated at a chord Reynolds number of 6.5 to 7.5 million. With a polished leading edge, 80 laminar flow was observed corresponding to N-factors greater than 12. Critically space DREs were applied a the leading edge to excite the crossflow instability and move transition forward. In this case, calibrated, multi-element hotfilm sensors were used to measure disturbance wall shear stress. The roughness height was varied from 0 to 50 microns both in the positive bumps and negative dimples sense. Thus, the disturbance amplitude variations were determined as a function of modulated DRE heights.

Descriptors:

• *LAMINAR FLOW
• *LEADING EDGES
• *SWEPT WINGS
• CALIBRATION
• CROSS FLOW
• DETECTORS
• FLIGHT TESTING
• FREE STREAM
• HELICOPTERS
• INSTABILITY
• ROUGHNESS
• SHEAR STRESSES
• VALIDATION
• VERTICAL ORIENTATION

Subject Categories:

• Aircraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE