Propagation of the Velocity Shear Front in Spin-up From Rest in a Cut-Cone

The behavior of the dominant azimuthal velocity field during spin-up from rest of a homogeneous fluid in a cut-cone is investigated. The fundamental mechanism of spin-up process is recapitulated. In line with the classical flow model of Wedemeyer, the importance of the meridional circulation, driven by the Ekman layers, is stressed. The experimental apparatus, together with the image processing technique of the visualized flow data, is described. The reliability and accuracy of this experimental method are validated by performing parallel measurements using an LDV system. The experimental results clearly indicate that the azimuthal velocity shear front propagates faster as the incline angle of the side wall decreases. In the rotating zone of the interior, the azimuthal velocities are larger in magnitude in a cut-cone than in a circular cylinder of comparable size. Plausible physical explanations are offered, and the experimental observations are supportive of these physical arguments.

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Experimental Investigation of the Flow With a Free Surface in an Impulsively Rotating Cylinder

Journal of Fluids Engineering ◽

10.1115/1.2909487 ◽

1991 ◽

Vol 113 (2) ◽

pp. 245-249 ◽

Cited By ~ 7

Author(s):

Sangmin Choi ◽

Jae Won Kim ◽

Jae Min Hyun

Keyword(s):

Image Processing ◽

Experimental Investigation ◽

Free Surface ◽

Processing Technique ◽

Velocity Shear ◽

Image Processing Technique ◽

Laser Doppler Velocimeter ◽

Numerical Predictions ◽

Shear Front ◽

Propagating Shear

An experimental investigation was made of the impulsive spin-up from rest of a liquid in a partially filled cylindrical container. The main impetus was placed on delineating the effects of the presence of a free surface on the transient development of flow. Of particular interest were the situations in which the free surface intersected either or both of the endwall disks during the course of spin-up. Extensive flow visualizations were carried out by using suspended metal particles. An image processing technique was utilized to determine accurately the propagating velocity shear front as well as the time-dependent free surface contour. Precise measurements of the fluids velocities were obtained by using a laser Doppler velocimeter. The transient velocity profiles were mapped out, and they were found to be in satisfactory agreement with the predictions based on the simplified analysis. The radial location, Rs(t), of the propagating shear front was measured by applying the image processing technique to the visualized azimuthal flow field. The experimental data were found to be consistent with the numerical predictions.

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A unified linear theory of homogeneous and stratified rotating fluids

Journal of Fluid Mechanics ◽

10.1017/s0022112067001053 ◽

1967 ◽

Vol 29 (3) ◽

pp. 609-621 ◽

Cited By ~ 73

Author(s):

V. Barcilon ◽

J. Pedlosky

Keyword(s):

Side Wall ◽

Extreme Case ◽

Ekman Layer ◽

Rotating Fluids ◽

Homogeneous Fluid ◽

Hybrid Features ◽

Wall Boundary Layer ◽

Ekman Layers ◽

Buoyancy Forces ◽

The One

A unified picture of the linear dynamics of rotating fluids with given arbitrary stratification is presented. The range of stratification which lies outside the region of validity of both the theories of homogeneous fluids, $\sigma S < E^{\frac{2}{3}}$ and the strongly stratified fluids, σS > E½, is studied, where σS = vαgΔT/κΩ2L and E =v/ΩL2. The transition from one dynamics to the other is elucidated by a detailed study of the intermediate region E2/3 < σS < E½. It is shown that, within this intermediate stratification range, the dynamics differs from that of either extreme case, except in the neighbourhood of horizontal boundaries where Ekman layers are present. In particular the side wall boundary layer exhibits a triple structure and is made up of (i) a buoyancy sublayer of thickness (σS)−1/4E½ in which the viscous and buoyancy forces balance, (ii) an intermediate hydrostatic, baroclinic layer of thickness (σS)½ and (iii) an outer E¼-layer which is analogous to the one occurring in a homogeneous fluid. In the interior, the dynamics is mainly controlled by Ekman-layer suction, but displays hybrid features; in particular the dynamical fields can be decomposed into a ‘homogeneous component’ which satisfies the Taylor-Proudman theorem, and into a ‘stratified component’ which is baroclinic and which satisfies a thermal wind relation. In all regions the structure of the flow is displayed in detail.

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Experiments on spin-up and spin-down on a β-plane

Journal of Fluid Mechanics ◽

10.1017/s0022112094001722 ◽

1994 ◽

Vol 271 ◽

pp. 153-172 ◽

Cited By ~ 1

Author(s):

W. J. Jillians ◽

T. Maxworthy

Keyword(s):

Ocean Circulation ◽

Large Scale ◽

Flow Characteristics ◽

Processing Technique ◽

Image Processing Technique ◽

Homogeneous Fluid ◽

Video Record ◽

Homogeneous Models ◽

The One ◽

The Relationship

Here we study the spin-up and spin-down of a homogeneous fluid with a free surface on an experimental ‘β-plane’ and describe the important features for both cases over a range of parameters. Quantitative values are found for the velocity fields using a new image processing technique that analyses a video record of particle motion and stores the results digitally. Streamlines, pressure fields and vorticity values are found by interpolation techniques and result in a complete description of the flow characteristics. We discuss the relationship between the results of these experiments and those observed in large-scale homogeneous models of ocean circulation, e.g. Moore (1963). This study extends the work of van Heijst et al. (1990) to the case of spin-up in a rectangular container but of non-uniform depth and we note the differences to and similarities with their observations. It is related, also, to more recent results of Maas et al. (1992), who considered spin-up on a β-plane but in a tank of very different proportions to the one considered here.

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Flows in Rotation Cylinder Filled With Polymer Solutions

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2006-98334 ◽

2006 ◽

Author(s):

Jae Won Kim ◽

JaeMin Hyun ◽

Eun Young Ahn

Keyword(s):

Apparent Viscosity ◽

Polymer Solutions ◽

Side Wall ◽

Velocity Shear ◽

Working Fluid ◽

Shear Rates ◽

Ctab Solution ◽

Applied Shear Stress ◽

Shear Front ◽

Solid Walls

This investigation deals with the spin-up flows in a circular container of aspect ratio, 2.0. Shear front is generated in the transient spin-up process of the present flow system and it is propagating from the side wall to the central axis in a rotating container. Propagation of the shear front to the axis in a rotating container means the region behind the shear front acquires an angular momentum transfer from the solid walls. Propagating speed of the shear front depends on the apparent viscosity of polymer solution. Two kinds of polymer solutions are considered as a working fluid: one is CMC and the other is CTAB solution. CMC solution has larger apparent viscosity than that of water at the present applied shear stress, and CTAB shows varying apparent viscosities depending on the applied shear rates. Transient and spatial variations of the apparent viscosities of the present polymer solutions (CTAB and CMC) cause different propagating speeds of the shear front. In practice, CMC solution that has larger values of apparent viscosity than that of water always shows rapid approach to the steady state in comparison of the behavior of the flows with water. However, for the CTAB solution, the propagating speed of the shear front changes with the local magnitude of its apparent viscosity. Consequently, the prediction of Wedemeyer’s including viscosity in the propagating speed of the velocity shear front quantitatively agrees with the present experimental results.

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A New Image Processing Technique for STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052171 ◽

1974 ◽

Vol 32 ◽

pp. 432-433

Author(s):

Yasushi Kokubo ◽

Hirotami Koike ◽

Teruo Someya

Keyword(s):

Electron Microscopy ◽

Image Processing ◽

Scanning Electron Microscopy ◽

Elastic Scattering ◽

Field Emission ◽

Processing Technique ◽

Image Processing Technique ◽

Energy Analyzer ◽

Scanning Microscope ◽

Scanning Electron

One of the advantages of scanning electron microscopy is the capability for processing the image contrast, i.e., the image processing technique. Crewe et al were the first to apply this technique to a field emission scanning microscope and show images of individual atoms. They obtained a contrast which depended exclusively on the atomic numbers of specimen elements (Zcontrast), by displaying the images treated with the intensity ratio of elastically scattered to inelastically scattered electrons. The elastic scattering electrons were extracted by a solid detector and inelastic scattering electrons by an energy analyzer. We noted, however, that there is a possibility of the same contrast being obtained only by using an annular-type solid detector consisting of multiple concentric detector elements.

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A Comparative Study of Ant and Genetic Algorithms in Digital Mammography

International Journal of Scientific Research in Computer Science Engineering and Information Technology ◽

10.32628/cseit183863 ◽

2018 ◽

pp. 194-200

Author(s):

J. Magelin Mary ◽

Chitra K. ◽

Y. Arockia Suganthi

Keyword(s):

Genetic Algorithm ◽

Image Processing ◽

Medical Image ◽

Medical Image Processing ◽

Processing Technique ◽

Input Image ◽

Image Processing Technique ◽

Computational Time ◽

Image Mining ◽

The Individual

Image processing technique in general, involves the application of signal processing on the input image for isolating the individual color plane of an image. It plays an important role in the image analysis and computer version. This paper compares the efficiency of two approaches in the area of finding breast cancer in medical image processing. The fundamental target is to apply an image mining in the area of medical image handling utilizing grouping guideline created by genetic algorithm. The parameter using extracted border, the border pixels are considered as population strings to genetic algorithm and Ant Colony Optimization, to find out the optimum value from the border pixels. We likewise look at cost of ACO and GA also, endeavors to discover which one gives the better solution to identify an affected area in medical image based on computational time.

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An Enhanced Technique for Classification of Fruits using Shape Color and Texture Features

International Journal of Advanced Research in Computer Science and Software Engineering ◽

10.23956/ijarcsse/v7i7/0107 ◽

2017 ◽

Vol 7 (7) ◽

pp. 408

Author(s):

Yashpal Jitarwal ◽

Tabrej Ahamad Khan ◽

Pawan Mangal

Keyword(s):

Image Processing ◽

Texture Features ◽

Automatic Classification ◽

Processing Technique ◽

Image Processing Technique ◽

Advance Technique ◽

Time Required ◽

Fruit Sorting ◽

Human Inspection

In earlier times fruits were sorted manually and it was very time consuming and laborious task. Human sorted the fruits of the basis of shape, size and color. Time taken by human to sort the fruits is very large therefore to reduce the time and to increase the accuracy, an automatic classification of fruits comes into existence.To improve this human inspection and reduce time required for fruit sorting an advance technique is developed that accepts information about fruits from their images, and is called as Image Processing Technique.

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