Accession Number:

AD0773664

Title:

Laser Interferometry of Unsteady, Underexpanded Jets,

Descriptive Note:

Corporate Author:

BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s):

• Oertel,Fritz H. , Jr

Report Date:

1974-01-01

Pagination or Media Count:

26.0

Abstract:

The report describes an experiment to obtain optical data for an unsteady, under-expanded axisymmetric jet issuing from a one inch diameter tube at supersonic velocity. A technique is described which has been found useful to obtain sequence photographic data for such transient processes. In this technique, a bleachable absorber is used to generate multiple laser pulses so that instantaneous images of the laser-illuminated event are swept onto a fixed film drum with a mirror rotating at approximately 16.2 mmmicrosecond. Comments on our experience with high voltage double-pulsing a Pockels cell are also included. Sequence multiple frame laser interferograms made by backlighting aMach-Zehnder optical interferometer used to observe the flow are shown and discussed. Single frame spark shadow photographs which give qualitative support to the interferograms are also shown. Author

Descriptors:

• *JET FLOW
• *INTERFEROMETRY
• *LASERS
• Q SWITCHING
• FLOW FIELDS
• FLOW VISUALIZATION
• SHOCK TUBES

Subject Categories:

• Test Facilities, Equipment and Methods
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE