Accession Number : ADA316875

Title :   Instrumentation for Investigating Precursors to High Reynolds Number Unsteady Flow Separation on Pitching Airfoils.

Descriptive Note : Final rept. 15 Jul 94-14 Jul 95,

Corporate Author : MISSISSIPPI UNIV UNIVERSITY

Personal Author(s) : Sinha, Sumon K. ; Pal, Dipankar ; Banerjee, Debjyoti ; Pandey, Mukesh ; Baker, Chuck

PDF Url : ADA316875

Report Date : 10 SEP 1996

Pagination or Media Count : 52

Abstract : A pitching airfoil test facility has been developed to enable investigating the unsteady flow separation process on helicopter rotor blades under flow conditions which replicate the viscous-inviscid interactions. The facility is capable of operating at chord based Reynolds numbers of 106 and reduced frequencies of 0.23 while maintaining the Mach number below 0.15. A multi-element compliant wall sensor has been developed to measure pressure fluctuations just preceding the emption of the boundary layer. Following successful implementation on cylinders and non-pitching airfoils, this transducer has been used to detect the propagation of wall pressure fluctuations in the neighborhood of the separation point. Preliminary data obtained by sampling simultaneously the data from eight transducer strips has revealed patterns characteristic to the boundary layer emption process.

Descriptors :   *PRECURSORS, *AIRFOILS, *UNSTEADY FLOW, *FLOW SEPARATION, *REYNOLDS NUMBER, MEASUREMENT, PITCH(MOTION), DETECTORS, INTERACTIONS, BOUNDARY LAYER, HELICOPTER ROTORS, ROTOR BLADES(ROTARY WINGS), VARIATIONS, SAMPLING, PRESSURE, WALLS, SEPARATION, TRANSDUCERS, FLOW, INVISCID FLOW, VISCOUS FLOW, TEST FACILITIES, VARIABLE PRESSURE, COMPLIANT WALLS.

Subject Categories : Aircraft
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE