Optical fibre probe measurements of bubbly flow in hydraulic jumps

Murzyn, Frédéric; Mouazé, Dominique; Chaplin, J.R.

doi:10.1016/j.ijmultiphaseflow.2004.09.004

Cited by 142 publications

(156 citation statements)

References 13 publications

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“…One of the most important in terms of both fundamental scientific under standing and technological application, is the mechanism by which air bubbles are entrained underneath the free surface. A significant fraction of the total air amount entrained by the breaker is known to occur at the leading edge [3,21], where the flow separation oc curs, which is consistent with the flow structure proposed by Long uet Higgins and Turner [13] and Cointe and Tulin [4] among others. This mechanism is particularly important in weak breakers.…”

supporting

confidence: 86%

Dynamics of large turbulent structures in a steady breaker

Rodríguez-Rodríguez

Marugán-Cruz

Aliseda

et al. 2011

Experimental Thermal and Fluid Science

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a b s t r a c tThe flow near the leading edge of a steady breaker has been studied experimentally using Bubble Image Velocimetry (BIV) with the aim of characterizing the dynamics of the large eddies responsible for air entrainment. It is well reported in the literature, and confirmed by our measurements of the instanta neous velocity field, that this flow shares some important features with the turbulent shear layer formed between two parallel semi infinite streams with different velocities. Namely, the formation of a periodic array of coherent vortices, the constant convective velocity of those vortices, the linear relation between their size and their downstream position and the self similar structure of both mean velocity profiles and Reynolds shear stresses. Nonetheless, important differences exists between the dynamics of the large eddies in a steady breaker and those in a free shear layer. Particularly, the convective velocity of these large structures is slower in a steady breaker and, consistent with this, their growth rates are larger. A physical interpretation of these differences is provided together with a discussion of their implications. To support our measurements and conclusions, we present a careful analysis of the accuracy of the BIV technique in turbulent flows with large bubbles.

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supporting

confidence: 86%

Dynamics of large turbulent structures in a steady breaker

Rodríguez-Rodríguez

Marugán-Cruz

Aliseda

et al. 2011

Experimental Thermal and Fluid Science

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“…The maximum air content in the air diffusion layer decreased with distance from the jump toe and the data are believed to follow closely both power law and exponential decay functions as shown by Chanson and Brattberg [6] and Murzyn et al [7]. The corresponding decay correlations are: where C 1p , C 2p , C 1e and C 2e are the numerical coefficients of power law and exponential decay functions.…”

Section: Froude Number Effect On Air-water Flow Propertiessupporting

confidence: 60%

“…Chanson and Brattberg [6] documented vertical distributions of void fractions, bubble count-rates and air-water velocities in the hydraulic jump with inflow Froude numbers Fr 1 of 6.33 and 8.48. Murzyn et al [7] measured detailed air-water flow properties in an hydraulic jump with inflow Froude numbers from 2.0 to 4.8. Table 1 lists the main characteristics of the experimental investigations of air entrainment in hydraulic jump flows that are available in literature.…”

Section: Forewordmentioning

confidence: 99%

“…(2) and (3), the diffusivity D t describes the advective diffusion process in the air-water shear layer downstream of a point source at x = x 1 and y = d 1 , i.e., the jump toe. Equation (4) is not applicable to a hydraulic jump roller free-surface, although it does fit the data [7] as shown in Fig. 9.…”

Section: Basic Patterns Of Air-water Flow Properties In the Hydraulicmentioning

confidence: 99%

“…(4). The intersection between the two lines defines a dimensionless elevation Y * /d 1 [7], which represents the upper vertical boundary of the air diffusion layer and is a meaningful parameter of air entrainment process.…”

Section: Basic Patterns Of Air-water Flow Properties In the Hydraulicmentioning

confidence: 99%

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Experimental analysis of Froude number effect on air entrainment in the hydraulic jump

Gualtieri

Chanson

2007

Environ Fluid Mech

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A hydraulic jump is characterized by strong energy dissipation and mixing, large-scale turbulence, air entrainment, waves, and spray. Despite recent pertinent studies, the interaction between air bubbles diffusion and momentum transfer is not completely understood. The objective of this paper is to present experimental results from new measurements performed in a rectangular horizontal flume with partially developed inflow conditions. The vertical distributions of the void fraction and the air bubbles count rate were recorded for inflow Froude number Fr 1 in the range from 5.2 to 14.3. Rapid detrainment process was observed near the jump toe, whereas the structure of the air diffusion layer was clearly observed over longer distances. These new data were compared with previous data generally collected at lower Froude numbers. The comparison demonstrated that, at a fixed distance from the jump toe, the maximum void fraction C max increases with the increasing Fr 1 . The vertical locations of the maximum void fraction and bubble count rate were consistent with previous studies. Finally, an empirical correlation between the upper boundary of the air diffusion layer and the distance from the impingement point was derived.

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Area‐alterable liquid electrode capacitance sensor for water holdup measurement in oil–water two‐phase flow

Yang

Wang

et al. 2021

Asia-Pacific J Chem Eng

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Oil–water two‐phase flow exists widely in the process of petroleum industry. The water holdup is an important parameter but difficult to measure. In this paper, we develop an area‐alterable liquid electrode capacitance sensor for water holdup measurement in oil–water two‐phase flow. The capacitance sensor has a relatively high measurement sensitivity and a good linearity in the full range of the water holdup, from 0% to 100%. Meanwhile, a firing technology of insulating layer is presented to guarantee the characteristics of the capacitance sensor with high temperature resistance, corrosion resistance, and non‐stickiness. The static performance of the capacitance sensor is validated theoretically and experimentally. Vertical upward oil–water two‐phase flow experiments indicate that the developed capacitance sensor has good performance for water holdup measurement with average relative error of 10% in the full range of the water holdup. Based on the output signal of the sensor, the information of flow structure can be also estimated in different flow patterns.

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Optical fibre probe measurements of bubbly flow in hydraulic jumps

Cited by 142 publications

References 13 publications

Dynamics of large turbulent structures in a steady breaker

Dynamics of large turbulent structures in a steady breaker

Experimental analysis of Froude number effect on air entrainment in the hydraulic jump

Area‐alterable liquid electrode capacitance sensor for water holdup measurement in oil–water two‐phase flow

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