On a Method of the Concentration Measurement by the Use of Light Absoption Law

Nakamura, Ikuo; Miyata, Masafumi; Sakai, Yasuhiko

doi:10.1299/jsme1958.26.1357

Cited by 6 publications

(5 citation statements)

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“…As the numerical camera is set in front of the experimental model, the recorded images, caught at various intervals of time, are analyzed by the methodology described in [18]. Based on the light absorption properties of a dye [16] as well as on the detector properties (spectral answer, transfer function), this technique transforms the recorded signal into reduced concentration at any point of the cell, by taking into account even a possible spacetime lighting non-uniformity. …”

Section: Experimental Devicementioning

confidence: 99%

Experimental and numerical study of the validity of Hele–Shaw cell as analogue model for variable-density flow in homogeneous porous media

Oltéan

Golfier

Buès

2008

Advances in Water Resources

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Section: Experimental Devicementioning

confidence: 99%

Experimental and numerical study of the validity of Hele–Shaw cell as analogue model for variable-density flow in homogeneous porous media

Oltéan

Golfier

Buès

2008

Advances in Water Resources

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“…An aqueous solution of D.F. Orange (direct dye) was used (Nakamura et al 1983) as the diffusing matter.…”

Section: Experimental Apparatus and Conditionsmentioning

confidence: 99%

“…Therefore, the sampling volume is 1.37 x C.C. (see Nakamura et al 1983). The output signals of the concentration-measuring circuit were recorded over 150 s using a data recorder (SONEY, Type FR-3215W; the high cut-off frequency is 10 kHz).…”

Section: Experimental Apparatus and Conditionsmentioning

confidence: 99%

“…Recently, a light-scattering method (Gad-el-Hak & Morton 1979;Becker et al 1966), a laser-Raman scattering method (Birch et al 1978) and a heat tagging method (Belorgey, Nguyen & Trinite 1979) have been developed. In the present work, a modified light probe (Nakamura, Miyata & Sakai 1983) was used that detects a wider range of concentration than the earlier light probe (Lee & Brodkey 1963;Nye & Brodkey 1967b).…”

Section: Introductionmentioning

confidence: 99%

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Diffusion of matter by a non-buoyant plume in grid-generated turbulence

Nakamura¹,

Sakai

Miyata

1987

J. Fluid Mech.

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The turbulent diffusion process is investigated for a continuous point source of a non-buoyant plume in grid-generated water turbulence. Two kinds of biplanar grids with a mesh length of 10 mm and 20 mm were used. The mesh Reynolds numbers were 1480 and 2970, respectively. The mean and fluctuating concentration fields of aqueous dye solution were measured by the light absorption method. Experimental results for both grids were compared.For both grids, the mean concentration radial profiles proved to have a similar Gaussian shape, and the mean concentration on the plume axis obeys the hyperbolic decay law well. These mean concentration profiles and their decay show an excellent agreement with the results deduced from the similarity analysis for the mean concentration field.Radial profiles of the fluctuation r.m.s. value and relative intensity (i.e. the ratio of the r.m.s. value to the mean concentration) were found also to be nearly similar, and the centreline r.m.s. value decays downstream as a hyperbola. The relative intensity on the centreline tends to increase slightly downstream. All experimental results obtained were much less scattered and more reliable than those reported earlier.The similarity for the concentration fluctuation intensity has been analysed using a thin-layer approximation. Also, an approximate analysis of the fluctuating concentration field is given by replacing the fluctuating concentration signal by a randomly spaced sequence of rectangular waves with various heights and widths.

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“…The concentration fields were measured by our own concentration fluctuation measuring system (see Nakamura, Miyata & Sakai 1983) incorporating a light absorption method. Light from a tungsten lamp is introduced into a sampling volume where the light intensity is reduced according t o the instantaneous concentration of the difiusing matter existing in the volume.…”

Section: Experimental Apparatus and Conditionsmentioning

confidence: 99%

The effect of a circular cylinder on the diffusion of matter by a plume

et al. 1993

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Experimental results are given for the mean and fluctuation concentration in a plume from a point source in grid-generated turbulence, which has developed so as to have a width comparable to the cylinder diameter, is disturbed by a cylinder with its axis intersecting the plume axis perpendicularly. It is shown that the disturbance effect of the cylinder appears in the upstream region of about 1.5 diameter from the stagnation point. As the stagnation point is approached, the increased travel time and the enhanced molecular diffusion cause a noticeable amplification of the dissipation of concentration variance. Also, the characteristics of some conditional statistics of the plume entrained in the wake are examined in order to investigate the intermittent structure of the plume meandering produced by the Kármán vortex street.

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On a Method of the Concentration Measurement by the Use of Light Absoption Law

Cited by 6 publications

References 0 publications

Experimental and numerical study of the validity of Hele–Shaw cell as analogue model for variable-density flow in homogeneous porous media

Experimental and numerical study of the validity of Hele–Shaw cell as analogue model for variable-density flow in homogeneous porous media

Diffusion of matter by a non-buoyant plume in grid-generated turbulence

The effect of a circular cylinder on the diffusion of matter by a plume

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