The phase reversal phenomenon at flow separation and reattachmentTests were conducted on two different airfoils, one of them in a low-turbulence tunnel, to detect laminar separation and turbulent reattachment locations. A 'nonintrusive' multielement sensor consisting of a large number of closely spaced individual nickel films was vacuum deposited on a thin substrate and bonded to the airfoil model surface. Each sensor element was a part of an independent constant temperature anemometer system. Time history as well as spectral analysis of signals from surface film gauges were used to determine the surface shear flow characteristics. A major breakthrough was achieved with the discovery of phase reversal in low-frequency dynamic shear stress signals across regions of flow separation and reattachment.
Document ID
19880035074
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Stack, J. Pete (NASA Langley Research Center Hampton, VA, United States)
Mangalam, S. M. (NASA Langley Research Center Hampton, VA, United States)
Kalburgi, V. (Analytical Services and Materials, Inc. Hampton, VA, United States)