Journal of Japan Society of Fluid Mechanics

Bifurcation diagram for two-dimensional steady flow and unsteady solutions in a curved square duct

Rabindra Nath Mondal, Yoshito KAGA, Toru HYAKUTAKE, Shinichiro YANASE

2008 Volume 27 Issue 4 Pages 277-280
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.277

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Measurements of Dispersed Multiphase Flow

[in Japanese], [in Japanese]

2008 Volume 27 Issue 4 Pages 281
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.281

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Measurement of bubbly flow using ultrasonic velocity profile method

Hiroshige KIKURA, Hideki MURAKAWA, Masanori ARITOMI

2008 Volume 27 Issue 4 Pages 283-294
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.283

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Measurement of Solid-Gas Two Phase Flow Concentration by Electrical Process Tomography Method

Masahiro TAKEI

2008 Volume 27 Issue 4 Pages 295-302
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.295

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An electrical capacitance PT is a noninvasive technique with the potential to visualize particle behavior in a cross-section of a multiphase flow. In this review, firstly, a fundamental structure and overview of the capacitance PT are explained. Next, a new reconstruction method called Generalized Vector Sampled Pattern Matching (GVSPM) is explained for resolving an ill-posed inverse problem. This accurate reconstruction is accomplished using an objective function that is calculated as the inner product calculation between the experimental capacitance and the reconstructed image capacitance. Lastly, the industrial application of the capacitance PT is explained.

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Simultaneous Measurements of Droplet Diameter and Velocity Using Phase Doppler Anemometer (PDA/PDPA)

Nobuyuki KAWAHARA, Eiji TOMITA

2008 Volume 27 Issue 4 Pages 303-310
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.303

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In this report, simultaneous measurements of droplet diameter and velocity using phase Doppler anemometer (PDA/PDPA) are explained. Obtained knowledge of spray and atomization characteristics using simultaneous measurements of droplet diameter and velocity are mentioned in the case of unsteady spray from a gasoline injector. rinciple of phase Doppler anemometer and key points of measurement parameters, such as laser power and measurement volume, and so on, are described. Moreover, we make data analysis and discussion on spray characteristics of unsteady spray from a gasoline injector.

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Visualization of Bubble and Sea Spray at Air-Water Interface

Microscopic Characteristics of Sea Surface Wave Breaking

Nobuhito MORI, Yasunori WATNBE

2008 Volume 27 Issue 4 Pages 311-320
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.311

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A wave breaking in the surf zone generates sea bubbles into the sea and releases air spray into the atmosphere. The sizes of air bubbles and spray are widely distributed from micrometer to centimeter. Moreover, these bubbles and spray are generated inhomogeneously both temporally and spatially. The two-phase flow measurements using imaging technique for two-dimensional bubble measurements are summarized for the surf zone breaking waves. The characteristics of air bubbles and sprays in the surf zone such as number distributions, bubble size spectra, and turbulent characteristics of fluid velocity are reviewed based on the visualization technique developed recently.

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Fluid Dynamics of Bubbly Flow Studied with PIV

Yuichi MURAL

2008 Volume 27 Issue 4 Pages 321-328
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.321

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Bubbly flows have multi-dimensional structure that involves plural phenomena with different wavelengths. PIVparticle image velocimetry, therefore, is suitably applied for measuring their spatial organization. In addition, kinematics of bubble and PIV scheme correlate mathematically since they deal with motion of dispersions mixed in flow. Namely, development of PIV system and study on bubbly flows progress in parallel to contribute to each other. In this paper, several experimental demonstrations of PIV application are reported, which features the characteristics of bubbly flow.

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Deformation and Internal Flows of a Cylinder with a Flexible Wall Oscillated by an External Flow

Masao YOKOYAMA, Osamu MOCHIZUKI

2008 Volume 27 Issue 4 Pages 329-336
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.329

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We investigated a deformation of a cylinder with a flexible wall and its internal flow induced by excitation of the external flow around the cylinder through a numerical simulation. The drag coefficient of the deformed cylinder became larger than that of a circular cylinder. Two rear portions of the cylinder vibrated with the vortex shedding frequency. The alternate flow between these two portions inside the cylinder was induced by the rear vibrating wall

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Eigen modes of a linear shear flow in shallow water on an equatorial β-plane

Hiroshi TANIGUCHI, Masaki ISHIWATARI

2008 Volume 27 Issue 4 Pages 337-338
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.337

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Eigen modes of a linear shear flow in shallow water on an equatorial β-plane are obtained over a wide parameter range. High-order unstable modes, neutral modes, and continuous modes are examined based on the results of Taniguchi and Ishiwatari (2006) that investigates mainly the lowest order most unstable modes. It is found that some continuous modes have equatorial Rossby wave like structures, and that high-order zonally symmetric unstable modes are caused by resonance between eastward mixed Rossby-gravity modes and continuous modes or by resonance between eastward inertial gravity modes and continuous modes. Neutral modes whose dispersion curves intersect with nearby dispersion curves of other neutral modes are also examined. Behaviors of dispersion curves of equatorial Kelvin modes and westward mixed Rossby-gravity modes are observed in cases that the two curves come closer.

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Chapter 4: How to analyze a Hypersonic Flow

Hirotoshi KUBOTA

2008 Volume 27 Issue 4 Pages 339-346
Published: August 25, 2008
Released on J-STAGE: October 22, 2010

DOIhttps://doi.org/10.11426/nagare1982.27.339

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[in Japanese]

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