Direct velocity measurement in low-speed water flows by double-wire hydrogen-bubble technique

1983 ◽  
Vol 1 (2) ◽  
pp. 111-112 ◽  
Author(s):  
Y. Iritani ◽  
N. Kasagi ◽  
M. Hirata
Keyword(s):  
Velocity Measurement ◽  
Hydrogen Bubble ◽  
Low Speed ◽  
Water Flows ◽  
Hydrogen Bubble Technique

Use of Hydrogen Bubbles for Quantitative Determination of Time-Dependent Velocity Fields in Low-Speed Water Flows

1965 ◽  
Vol 87 (2) ◽  
pp. 429-444 ◽  
Author(s):  
F. A. Schraub ◽  
S. J. Kline ◽  
J. Henry ◽  
P. W. Runstadler ◽  
A. Littell
Keyword(s):  
Quantitative Measurement ◽  
Operating Experience ◽  
Visual Observation ◽  
Low Frequencies ◽  
Low Speed ◽  
Water Flows ◽  
Hydrogen Bubbles ◽  
History Of ◽  
Hydrogen Bubble Technique

Improved flow-visualization methods based on the hydrogen-bubble technique are described. Use of “combined-time-streak markers” allows quantitative measurement of the instantaneous velocity field in a plane as a function of time in low-speed water flows. Adaptation to a great variety of situations using different probe techniques is possible. Disturbance to the flow is very small. Adequate accuracy is obtainable. The method offers the advantage of simultaneous visual observation of the flow structure and quantitative measurement of velocity over a finite region. It also allows some types of measurement not previously possible. Limitations of the method include its restriction to low-speed water flows and the observation of fluctuations only at low frequencies. Practical difficulties occur due to probe frangibility and problems of obtaining uniform bubble production. Part 1 describes the underlying concepts, summarizes the history of the method and describes operating experience to date at Educational Services, Incorporated, and Stanford University. Part 2 is a detailed analysis of the uncertainties in velocity measurements using combined-time-streak markers formed by hydrogen bubbles.

Application of the Hydrogen-Bubble Technique for Velocity Measurements in Thin Liquid Films

1973 ◽  
Vol 40 (2) ◽  
pp. 321-325 ◽  
Author(s):  
W. C. Thomas ◽  
J. C. Rice
Keyword(s):  
Velocity Profiles ◽  
Liquid Films ◽  
Momentum Equation ◽  
Thin Liquid Films ◽  
Falling Film ◽  
Hydrogen Bubble ◽  
Velocity Measurements ◽  
Long Distance ◽  
Simplified Solution ◽  
Hydrogen Bubble Technique

A unique adaptation of the hydrogen-bubble flow visualization method was applied to measure velocity profiles and film thicknesses of very thin films on an inclined plane wall. Data were obtained in the three flow regions for a developing falling film with an initially uniform velocity profile and thickness ≤0.1 in. The measured profiles compared more favorably with parabolic profiles in the intermediate fully developed region than in the initial developing region. However, measured film thicknesses compared favorably with a simplified solution of the integral momentum equation based on parabolic velocity profiles. The results confirm the theoretical prediction that a relatively long distance may be required even for a thin film before nonaccelerating flow with a constant film thickness is obtained and Nusselt’s classical analysis applies. The experimental technique was shown to be a practical experimental method for obtaining data for the two-dimensional laminar flow of thin liquid films.

An Evaluation of the Hydrogen Bubble Technique for the Quantitative Determination of Fluid Velocities Within Clear Tubes

1967 ◽  
Vol 89 (4) ◽  
pp. 771-777 ◽  
Author(s):  
W. Davis ◽  
R. W. Fox
Keyword(s):  
Quantitative Determination ◽  
Flow Visualization ◽  
Steady Flow ◽  
Hydrogen Bubble ◽  
Entrance Length ◽  
Fluid Velocities ◽  
Clear Plastic ◽  
Hydrogen Bubble Technique

The hydrogen bubble technique for flow visualization is modified for quantitative determination of velocity of water flowing in clear plastic tubes. Calibration tests are reported showing the accuracy which may be expected of the technique. The technique is verified by application to the determination of the hydrodynamic entrance length in steady flow.

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