A Phase Locked High Speed Real-Time Interferometry System for Large Amplitude Unsteady Flows
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Authors
Chandrasekhara, M.S.
Squires, D.D.
Wilder, M.C.
Carr, L.W.
Kutler, Paul (Technical Monitor)
Subjects
INTERFEROMETRY
HIGH SPEED
DESIGN ANALYSIS
FABRICATION
AERODYNAMIC STALLING
AIRFOILS
FLOW DISTRIBUTION
UNSTEADY FLOW
PHASE LOCKED SYSTEMS
ANGLE OF ATTACK
ACTUATORS
BOUNDARY LAYER SEPARATION
DIFFRACTION
LASER OUTPUTS
LIGHT BEAMS
MICROCOMPUTERS
SUBSONIC SPEED
REAL TIME OPERATION
HIGH SPEED
DESIGN ANALYSIS
FABRICATION
AERODYNAMIC STALLING
AIRFOILS
FLOW DISTRIBUTION
UNSTEADY FLOW
PHASE LOCKED SYSTEMS
ANGLE OF ATTACK
ACTUATORS
BOUNDARY LAYER SEPARATION
DIFFRACTION
LASER OUTPUTS
LIGHT BEAMS
MICROCOMPUTERS
SUBSONIC SPEED
REAL TIME OPERATION
Advisors
Date of Issue
1994-01
Date
Jan 01, 1994
Publisher
Language
Abstract
A high speed phase locked interferometry system has been designed and developed for real-time measurements of the dynamic stall flow over a pitching airfoil. Point diffraction interferograms of incipient flow separation over a sinusoidally oscillating airfoil have been obtained at rates of up to 20 KHz and for free stream Mach numbers of 0.3 and 0.45. The images were recorded on ASA 125 and ASA 400 film using a drum camera. Special electronic timing and synchronizing circuits were developed to trigger the laser light source from the camera, and to initiate acquisition of the interferogram sequence from any desired phase angle of oscillation. The airfoil instantaneous angle of attack data provided by an optical encoder was recorded via a FIFO and in EPROM into a microcomputer. The interferograms have been analyzed using software developed in-house to get quantitative flow density and pressure distributions.
Type
Preprint
Description
Seventh International Symposium on Applications of Laser Techniques to Fluid Mechanics; 11-14 Jul. 1994; Lisbon; Portugal
Series/Report No
Department
Organization
Ames Research Center
Identifiers
NPS Report Number
Sponsors
Funder
RTOP 505-59-53
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.