Abstract

Previous methods for analyzing double-exposed speckle photographs provide point-by-point velocity information by using two-dimensional Fourier analysis, or constant velocity contours by using spatial filtering techniques. A new method using an anamorphic optical system to measure one component of the velocity throughout a section of the flow is analyzed and demonstrated. A laser sheet, thin in the x direction and extended in the y direction, is used to probe a line of the photograph of which the anamorphic optical system forms a one-dimensional Fourier transform in the x direction and images the speckle pattern in the y direction for measuring the x-velocity component. This results in curved fringes, which have a local spacing inversely proportional to the x-velocity component at that point. Thus it is possible to measure a velocity component along a selected line in the flow. This differs from spatial filtering techniques that produce contours showing the points where a selected velocity occurs.

© 1986 Optical Society of America

Full Article  |  PDF Article
Related Articles
Particle-image velocimetry: improving fringe signal-to-noise ratio with a two-step photographic process. Part II

C. J. D. Pickering and N. A. Halliwell
J. Opt. Soc. Am. A 2(10) 1721-1724 (1985)

Measuring fluid velocities with speckle patterns

D. B. Barker and M. E. Fourney
Opt. Lett. 1(4) 135-137 (1977)

Equal velocity fringes in a Rayleigh-Benard flow by a speckle method

Roland Meynart
Appl. Opt. 19(9) 1385-1386 (1980)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (4)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (6)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription