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Experimental investigation of unsteady flows at large incidence angles in a linear oscillating cascadeThe aerodynamics of a cascade of airfoils oscillating in torsion about the midchord is investigated experimentally at a large mean incidence angle and, for reference, at a low mean incidence angle. The airfoil section is representative of a modern, low aspect ratio, fan blade tip section. Time-dependent airfoil surface pressure measurements were made for reduced frequencies up to 0.8 for out-of-phase oscillations at Mach numbers up to 0.8 and chordal incidence angles of 0 deg and 10 deg. For the 10 deg chordal incidence angle, a separation bubble formed at the leading edge of the suction surface. The separated flow field was found to have a dramatic effect on the chordwise distribution of the unsteady pressure. In this region, substantial deviations from the attached flow data were found with the deviations becoming less apparent in the aft region of the airfoil for all reduced frequencies. In particular, near the leading edge the separated flow had a strong destabilizing influence while the attached flow had a strong stabilizing influence.
Document ID
Document Type
Conference Paper
Buffum, Daniel H. (NASA Lewis Research Center Cleveland,OH United States)
King, Aaron J. (California Univ. Davis, CA United States)
Capece, Vincent R. (California Univ. Davis, CA United States)
El-Aini, Yehia M. (Pratt and Whitney Aircraft West Palm Beach, FL United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1996
Subject Category
Aircraft Propulsion and Power
Report/Patent Number
NAS 1.15:107283
AIAA Paper 96-2823
Meeting Information
Joint Propulsion Conference(Lake Buena Vista, FL)
Funding Number(s)
PROJECT: RTOP 505-62-10
Distribution Limits
Work of the US Gov. Public Use Permitted.

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NameType 19960048688.pdf STI