Laser Interferometry of Unsteady, Underexpanded Jets,
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 mm/microsecond. (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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1974
- Accession Number
- AD0773664
Entities
People
- Fritz H. Oertel Jr.
Organizations
- Ballistic Research Laboratory