1990 Fiscal Year Final Research Report Summary
Trial for the Development of a Non-Contact Type Density Meter by the Inversion Method for the Continuous Spatial Measurement of Internal Waves and Stratified Flow Fields
| Project/Area Number |
01850119
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Research Field |
Hydraulic engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
HINO M. Tokyo Institute of Technology, Dept. of Civil Eng., Prof., 工学部, 教授 (30016323)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUNISHI Y. Tohoku Univ., Dept. of Mech. End., Assist. Prof. (1989), 工学部機械工学科, 助教授 (60189967)
OOTAGURO T. Institute of Computational Fluid Dynamics, 実験研究部長
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| Project Period (FY) |
1989 – 1990
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| Keywords | Density-meter / Laser / Stratified flow / Non-contact measurement / Inversion method / Inverse estimation |
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| Research Abstract |
Generally, the density change of a liquid is measured using the change of electrical conductivity. The conventional density meter has the deficits that the probe itself disturbs the flow field and it can measure only the density change at the point.
The ray path of a laser beam is deflected when it is shed into a stratified fluid due to the change of the deflection ratio of light by the density difference of liquid. In many cases, this is unfavorable property for the flow measurement. This research aims at the development of a new type density meter using this property.
A functional form such as the polynominals, the Fourier series and other orthogonal functions which contain a few arbitrary parameters is assumed to express the density filed. The path of laser beams are calculated by solving the differential equitation of ray deflection. The true values of parameters are inversly estimated by the Marquardt method so as to minimize the squared errors between the calculated and measured points of laser ray emmission.
The position of laser ray emmission is measured precisely and quickly by PSD (Position Sensing Device). The direction of laser beam is changed by the combination of a rotating mirror and reflection mirrors, in order to increase the amount of information, i. e. The number of laser rays.
The density changes of stratified flow are correctly estimated for (a) one dimensional vertical density filed, (b) the internal waves of two-layered flow and (c) complicated density field around a isolated mountain model.
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