Abstract

A white-light speckle technique for measurement of flow velocities is described. The speckle patterns are formed by incoherent light at the image plane of the fluid illuminated section. The convection flow generated in a rectangular cell filled with silicone oil is studied with this technique. The flow velocities are obtained as the result of a point-by-point analysis. Alternatively, an overall picture of their spatial distribution is obtained by means of a whole-field filtering technique. The accuracy of the two methods of analysis is studied.

© 1982 Optical Society of America

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References

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  1. R. Grousson, S. Mallick, Appl. Opt. 16, 2334 (1977).
    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]

1980 (1)

1979 (1)

1978 (2)

K. Iwata, T. Hakoshima, R. Nagata, Opt. Commun. 25, 311 (1978).
[CrossRef]

P. Simpkins, T. Dudderar, J. Fluid Mech. 89, 665 (1978).
[CrossRef]

1977 (3)

1976 (1)

L. Celaya, J. M. Jonathan, S. Mallick, Opt. Commun. 18, 496 (1976).
[CrossRef]

1975 (1)

C. Forno, Opt. Laser Technol. 16, 217 (1975).
[CrossRef]

Asundi, A.

Barker, D. B.

Celaya, L.

L. Celaya, J. M. Jonathan, S. Mallick, Opt. Commun. 18, 496 (1976).
[CrossRef]

Chiang, F.-P.

Dudderar, T.

P. Simpkins, T. Dudderar, J. Fluid Mech. 89, 665 (1978).
[CrossRef]

T. Dudderar, P. Simpkins, Nature London 270, 45 (1977).
[CrossRef]

Forno, C.

C. Forno, Opt. Laser Technol. 16, 217 (1975).
[CrossRef]

Fourney, M. E.

Grousson, R.

Hakoshima, T.

K. Iwata, T. Hakoshima, R. Nagata, Opt. Commun. 25, 311 (1978).
[CrossRef]

Iwata, K.

K. Iwata, T. Hakoshima, R. Nagata, Opt. Commun. 25, 311 (1978).
[CrossRef]

Jonathan, J. M.

L. Celaya, J. M. Jonathan, S. Mallick, Opt. Commun. 18, 496 (1976).
[CrossRef]

Mallick, S.

R. Grousson, S. Mallick, Appl. Opt. 16, 2334 (1977).
[CrossRef] [PubMed]

L. Celaya, J. M. Jonathan, S. Mallick, Opt. Commun. 18, 496 (1976).
[CrossRef]

Meynart, R.

Nagata, R.

K. Iwata, T. Hakoshima, R. Nagata, Opt. Commun. 25, 311 (1978).
[CrossRef]

Simpkins, P.

P. Simpkins, T. Dudderar, J. Fluid Mech. 89, 665 (1978).
[CrossRef]

T. Dudderar, P. Simpkins, Nature London 270, 45 (1977).
[CrossRef]

Appl. Opt. (3)

J. Fluid Mech. (1)

P. Simpkins, T. Dudderar, J. Fluid Mech. 89, 665 (1978).
[CrossRef]

Nature London (1)

T. Dudderar, P. Simpkins, Nature London 270, 45 (1977).
[CrossRef]

Opt. Commun. (2)

K. Iwata, T. Hakoshima, R. Nagata, Opt. Commun. 25, 311 (1978).
[CrossRef]

L. Celaya, J. M. Jonathan, S. Mallick, Opt. Commun. 18, 496 (1976).
[CrossRef]

Opt. Laser Technol. (1)

C. Forno, Opt. Laser Technol. 16, 217 (1975).
[CrossRef]

Opt. Lett. (1)

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Figures (6)

Fig. 1
Fig. 1

Optical system for recording white-light speckles: W, white-light source; L1, big aperture converging lens; CH, electromechanical chopper; S1, S2, slits; L2 cylindrical lens; M, mirror; O, flow under study; L3, recording lens; and P, photographic plate.

Fig. 2
Fig. 2

Multiexposure photograph of the convection flow.

Fig. 3
Fig. 3

Young's fringe pattern for various fluid velocities at a 4-mm height: (a) x = 24 mm, υ = 0.53 mm/sec; (b) x = 14 mm, υ = 0.44 mm/sec; and (c) x = 16 mm, υ = 0.33 mm/sec.

Fig. 4
Fig. 4

Horizontal velocity components ● and vertical velocity components ○ at a height of 4 mm. The solid line represents the sinusoidal form fitted between the experimental measures of υx.

Fig. 5
Fig. 5

Filtered images with equal velocity component fringes: (a) Δυx = 0.37 mm/sec; and (b)Δυy = 0.37 mm/sec.

Fig. 6
Fig. 6

Two-dimensional map of the fluid velocity field: (a) horizontal velocity components, and (b) vertical velocity components with - -, υ = 0.49 mm/sec; -•-, υ = 0.37 mm/sec; and •••, υ = 0.25 mm/sec.

Equations (5)

Equations on this page are rendered with MathJax. Learn more.

| υ | = λ f t x M ,
υ ξ = n λ f t R M ,
Δ υ υ = Δ λ λ + Δ f f + Δ t t + Δ x x + Δ M M .
Δ λ λ 10 6 , Δ t t 10 2 , Δ x x 10 2 , and Δ M M 10 2 .
Δ υ ξ υ ξ = Δ λ λ + Δ f f + Δ t t + Δ R R + Δ M M .

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