scholarly journals The wobbling motion of single and two inline bubbles rising in quiescent liquid

2021 ◽  
Vol 33 (7) ◽  
pp. 073305
Author(s):  
Yuanwei Cao ◽  
Rafael Macián-Juan
Keyword(s):  

Author(s):  
Charles C. Maneri ◽  
Peter F. Vassallo

The dynamic behavior of single bubbles rising in quiescent liquid Suva (R134a) in a duct has been examined through the use of a high speed video system. Size, shape and velocity measurements obtained with the video system reveal a wide variety of characteristics for the bubbles as they rise in both finite and infinite media. This data, coupled with previously published data for other working fluids, has been used to assess and extend a rise velocity model given by Fan and Tsuchiya. As a result of this assessment, a new rise velocity model has been developed which maintains the physically consistent characteristics of the surface tension in the distorted bubbly regime. In addition, the model is unique in that it covers the entire range of bubble sizes contained in the spherical, distorted and planar slug regimes.



2021 ◽  
Author(s):  
Michael D. Mayer ◽  
Jonah Kadoko ◽  
Marc Hodes

Abstract We develop a two-dimensional model for the transient diffusion of gas from the cavities in ridge-type structured surfaces to a quiescent liquid suspended above them in the Cassie state to predict the location of the liquid vapor-interface (meniscus) as a function of time. The transient diffusion equation is numerically solved by a Chebyshev collocation (spectral) method coupled to the Young-Laplace equation and the ideal gas law. We capture the effects of variable meniscus curvature and, subsequently, when applicable, movement of triple contact lines. Results are presented for the evolution of the dissolved gas concentration field in the liquid and, when applicable, the time it takes for a meniscus to depin and that for longevity, i.e., the onset of the Cassie to Wenzel state transition. Two configurations are examined; viz., one where an impermeable membrane pressurizes the liquid above the ridges and one where hydrostatic pressure is considered and the top of the liquid is exposed to non-condensable gas.



2020 ◽  
Vol 59 (13) ◽  
pp. 6247-6257 ◽  
Author(s):  
Aarsee Dhindsa ◽  
Ravinder K. Wanchoo ◽  
Amrit P. Toor


1959 ◽  
Vol 10 (4) ◽  
pp. 274-280 ◽  
Author(s):  
E.A. Harvey ◽  
W. Smith


2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Kamil Wichterle ◽  
Marek Večeř ◽  
Marek Růžička

AbstractTwo perpendicular projections of rising bubbles were observed in counter-current downstream diverging flow. Evidently, the bubbles did not enter the boundary layer at the channel wall and a plug liquid flow assumption was acceptable in our experimental equipment. This confirmed that the experiment was appropriate for simulation of bubble rises in a quiescent liquid column. Recent data obtained by a high-speed camera permitted recording over a period of 60 s. Image analysis by a tailor-made program provided a time-series of quantities related to the position, size, and shape of bubbles. In addition to determination of the aspect ratio of the equivalent oblate ellipsoid, deviation from this shape was investigated in respect of the difference between the bubble’s centre of mass and the geometrical centre of bubble projection. Autocorrelation of the data indicated that the bubble inclination oscillated harmonically with a frequency of 5–10 Hz; cross correlation showed that the horizontal shift of the centre of mass, as well as the horizontal velocity, increased with increasing bubble inclination, and the vertical shift of the centre of mass increased with an increases in the absolute value of the bubble inclination. There is no significant phase shift in the oscillation of these quantities. The bulky bottom side of the bubbles is in accordance with the model of bubble oscillation induced by instability of the equilibrium of gravity and surface tension forces. The oscillation frequency dependence on surface forces (Eötvös number) is evident, while viscosity does not play a significant role in low-viscosity liquids. Therefore, vortex-shedding is more likely to be an effect of the oscillation and not its cause.



2021 ◽  
Vol 121 ◽  
pp. 110279
Author(s):  
Tomio Okawa ◽  
Kohei Kubo ◽  
Katsuyuki Kawai ◽  
Sota Kitabayashi


2004 ◽  
Vol 49 (9) ◽  
pp. 185-192 ◽  
Author(s):  
P. Winter ◽  
N. Jones ◽  
M. Asaadi ◽  
L. Bowman

This paper describes a project to investigate the odour of sewage sludge after anaerobic digestion. The impact of air stripping on the odour of liquid sludge and on the quality of the dewatered product was evaluated at a full-scale sludge treatment installation. A continuous and a batch air-stripping mode were tested. Odour samples were collected during air stripping from the liquid sludge and from the biosolids surface during long term storage. The biosolids were also analysed for hedonic tone and for their potential odour expressed as an odour unit per unit mass. The odour emission profiles for continuous and batch air stripping demonstrated a reduction in the overall (time weighted) emissions during a 24 hr-period compared with emissions from the quiescent liquid storage tank. The averaged specific odour emission rate (Esp) of the biosolids derived from the continuous process was only 13% of the Esp of the biosolids derived from unaerated liquid sludge during the first month of storage. The results of the total potential odour and the hedonic tone of the biosolids underpin the beneficial effects of the air stripping. Odour dispersion modelling showed a noticeable reduction in overall odour impact from the sludge centre when air stripping was applied. The reduction was primarily associated with the reduced odour from stockpiled biosolids. The continuous air-stripping mode appeared to provide the greatest benefits in terms of odour impact from site operations.



1996 ◽  
Vol 10 (3) ◽  
pp. 264-273 ◽  
Author(s):  
Shu TAKAGI ◽  
Yoichiro MATSUMOTO


1991 ◽  
Vol 25 (3) ◽  
pp. 519-524 ◽  
Author(s):  
Alex R. Gholson ◽  
John R. Albritton ◽  
R. K. M. Jayanty ◽  
J. E. Knoll ◽  
M. R. Midgett


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