1 June 1988 Velocity Field Visualization Using The Doppler-Picture Technique
Author Affiliations +
Proceedings Volume 0863, Industrial Optoelectronic Measurement Systems Using Coherent Light; (1988) https://doi.org/10.1117/12.943482
Event: 1987 Symposium on the Technologies for Optoelectronics, 1987, Cannes, France
Abstract
A novel technique for visualizing and measuring an entire velocity field with only one photograph has been developed by taking "Doppler-pictures" with a Michelson interferometer. The Doppler-picture gives information, either about the instantaneous velocity distribution of a fast moving and/or deforming solid reflecting surface, or about the instantaneous and local velocities of tracers passing through a light sheet that cuts the flow field under investigation. The light sheet is produced by a widened laser beam. The Doppler-shift of the frequencies of the light scattered by the tracers is transformed by a Michelson interferometer into varying light intensities, thereby shifting a given initial interference fringe pattern. Generally, the interference fringes are adjusted to a constant frequency of the scattered light, which must be straight, parallel and equi-distant. The light intensities also depend on the intensity of the scattered light, but this occurs only in the illuminated fringe regions. The dark fringe areas with no light remain practically uninfluenced by the varying intensities of the scattered light. That is why, it is only the dark fringes that can be used for determining the measured velocity field distribution in the evaluation of Doppler-pictures. The tracer velocities along the dark fringes can be obtained by simply measuring and comparing the shift of the dark fringes with the initial fringe pattern. This new visualization method will be described in principle, and the use of our Doppler-picture camera will be demonstrated with Doppler-pictures of (a) circular supersonic free air jets coming out of a Laval-nozzle, (b) a cutting torch outflow, (c) vortices, (d) moving shock waves showing the velocity rise across it and (e) a fast rotating solid drum.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Srulijes, J. Srulijes, F. Seiler, F. Seiler, A. George, A. George, } "Velocity Field Visualization Using The Doppler-Picture Technique", Proc. SPIE 0863, Industrial Optoelectronic Measurement Systems Using Coherent Light, (1 June 1988); doi: 10.1117/12.943482; https://doi.org/10.1117/12.943482
PROCEEDINGS
9 PAGES


SHARE
RELATED CONTENT

Interferometric Measurement Of Truss Joint Design Strengths
Proceedings of SPIE (December 24 1979)
Dual parallel-cavity Fabry-Perot interferometer
Proceedings of SPIE (May 29 1995)
Imaging white-light VISAR
Proceedings of SPIE (May 27 1997)
Phase-Conjugate Interferometry
Proceedings of SPIE (May 22 1984)
Principles of laser velocimetry with Doppler-pictures
Proceedings of SPIE (December 31 1991)

Back to Top