Unsteady Stall Penetration of an Oscillating Swept Wing,
UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT
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Results include 1 Mean angle of attach has little or no effect on wave speed which in all cases increases uniformly with reduced frequency. Motion amplitude also has little or no effect on wave speed. Mach number has a small but consistent effect on wave speed, with higher Mach numbers yielding slightly smaller wave speeds. 2 Sweep angle has a dominant effect on wave speed. The overall wave speed for the unswept wing is consistently greater than that for the swept wing by a factor of 1.5 to 2.0. This represents a major failure above stall for the cosine law normalization which has been shown to be consistently valid below stall. 3 Mach number has a dominant effect on vortex inception angle and static stall angle, with a decrease in both angles as the chordwise Mach number increases. 4 Vortex inception is substantially independent of amplitude of motion and mean angle of attack. and 5 Local wave speed differences associated with sweep are confined to the region of the blade aft of the 15 chord. Wave speeds are substantially the same for both sweep angles forward of this chord location.