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Journal ArticleDOI

Bubble characterization in horizontal air–water intermittent flow

TL;DR: In this article, an ensemble-averaged digital image processing technique was applied for detection of the liquid-gas interface with aid of a set of photo gates to synchronize bubble passage with image acquisition.
About: This article is published in International Journal of Multiphase Flow.The article was published on 2015-03-01. It has received 34 citations till now. The article focuses on the topics: Slug flow & Bubble.
Citations
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Journal ArticleDOI
TL;DR: In this article, the hydrodynamic characteristics of the near- transition to slug flow of air-water two-phase flow in horizontal pipes were investigated experimentally for inner pipe diameters of 16,mm, 26,mm and 50 mm.

35 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe four methods of noise reduction in cross-correlation measurements of water-air mixture flows in a horizontal pipeline, including signal spectrum filtering, discrete wavelet transformation, and Nadaraya-Watson kernel estimator.

34 citations

Journal ArticleDOI
TL;DR: An image processing technique was proposed in order to study the interfacial behavior of air-water slug two-phase flow in horizontal pipes and reveals the comprehensive characteristics of slug flow inizontal pipes.

32 citations

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the mechanism responsible for plug to slug transition and associated dynamics of bubble detachment from the elongated bubble using flow visualization and local velocity measurements using FASTCAM Photron camera and a 3D automated traverse system.

32 citations

Journal ArticleDOI
Yang Yang1, Dong Wang1, Pengman Niu1, Ming Liu1, Chao Zhang1 
TL;DR: In this paper, a phase-isolation method for vertical upward flow is developed to achieve a stable and uniform swirling core-annular flow pattern, and the behavior of the electromagnetic flowmeter is analyzed and an automatic image processing algorithm is developed.

31 citations

References
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Book
01 Dec 2003
TL;DR: 1. Fundamentals of Image Processing, 2. Intensity Transformations and Spatial Filtering, and 3. Frequency Domain Processing.
Abstract: 1. Introduction. 2. Fundamentals. 3. Intensity Transformations and Spatial Filtering. 4. Frequency Domain Processing. 5. Image Restoration. 6. Color Image Processing. 7. Wavelets. 8. Image Compression. 9. Morphological Image Processing. 10. Image Segmentation. 11. Representation and Description. 12. Object Recognition.

6,306 citations

Journal ArticleDOI
TL;DR: In this article, a generalized flow regime map based on this theory is presented, which is used for determining flow regime transitions in two-phase gas-liquid flow, and the mechanisms for transition are based on physical concepts and are fully predictive.
Abstract: Models are presented for determining flow regime transitions in two-phase gas-liquid flow. The mechanisms for transition are based on physical concepts and are fully predictive in that no flow regime transitions are used in their development. A generalized flow regime map based on this theory is presented.

2,420 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a broad investigation into the properties of steady gravity currents, in so far as they can be represented by perfect-fluid theory and simple extensions of it (like the classical theory of hydraulic jumps) that give a rudimentary account of dissipation.
Abstract: This paper presents a broad investigation into the properties of steady gravity currents, in so far as they can be represented by perfect-fluid theory and simple extensions of it (like the classical theory of hydraulic jumps) that give a rudimentary account of dissipation. As usually understood, a gravity current consists of a wedge of heavy fluid (e.g. salt water, cold air) intruding into an expanse of lighter fluid (fresh water, warm air); but it is pointed out in Q 1 that, if the effects of viscosity and mixing of the fluids at the interface are ignored, the hydrodynamical problem is formally the same as that for an empty cavity advancing along the upper boundary of a liquid. Being simplest in detail, the latter problem is treated as a prototype for the class of physical problems under study: most of the analysis is related to it specifically, but the results thus obtained are immediately applicable to gravity currents by scaling the gravitational constant according to a simple rule. In Q 2 the possible states of steady flow in the present category between fixed horizontal boundaries are examined on the assumption that the interface becomes horizontal far downstream. A certain range of flows appears to be possible when energy is dissipated; but in the absence of dissipation only one flow is possible, in which the asymptotic level of the interface is midway between the plane boundaries. The corresponding flow in a tube of circular cross-section is found in $3, and the theory is shown to be in excellent agreement with the results of recent experiments by Zukoski. A discussion of the effects of surface tension is included in 0 3. The two-dimensional energy-conserving flow is investigated further in Q 4, and finally a close approximation to the shape of the interface is obtained. In Q 5 the discussion turns to the question whether flows characterized by periodic wavetrains are realizable, and it appears that none is possible without a large loss of energy occurring. In $6 the case of infinite total depth is considered, relating to deeply submerged gravity currents. It is shown that the flow must always feature a breaking ‘head wave’, and various properties of the resulting wake are demonstrated. Reasonable agreement is established with experimental results obtained by Keulegan and others.

1,371 citations

Journal ArticleDOI
TL;DR: Govier and Aziz as mentioned in this paper used flow pattern maps for two-phase gas-liquid flow in horizontal pipes and compared them with the 5935 flow pattern observations currently contained in the UC Multiphase Pipe Flow Data Bank.

1,065 citations

Journal ArticleDOI
Dvora Barnea1
TL;DR: In this article, models for predicting flow-pattern transitions in steady gas-liquid flow in pipes are summarized and presented, incorporating the effect of fluid properties, pipe size and the angle of inclination in a unified way.

550 citations