Journal of Japan Society of Fluid Mechanics

[title in Japanese]

[in Japanese]

1995 Volume 14 Issue 6 Pages 409-410
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.409

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Study of Turbulence in Multiphase Flow

Escape from Mess

Yutaka TSUJI

1995 Volume 14 Issue 6 Pages 411-417
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.411

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First, research of turbulence modification in multiphase flow since 1950's is reviewed. Many experimental results have been reported since direct measurements using LVD was possible. It is found that large particles increase turbulence while small particle surpress it. However our understanding of multiphase flow turbulence is still primitive. Secondly, recent work based on discrete particle simulation made in Osaka University is introduced. Formation of particle cluster in gas-solid flows can be explained by inter-particle collision. Clusters calculated in a simulation produce strong turbulent fields which are similar to those practically observed in experiments.

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Numerical Simulations of Quasi-Streamwise Eddies in the Near-Wall Region

Yutaka MIYAKE

1995 Volume 14 Issue 6 Pages 418-426
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.418

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Some aspects of coherent structure, the quasi-streamwise eddies in particular, obtained by numerical simulation are discussed. The mechanism of self-substenance of the eddies and that of consecutive regeneration are briefly described using the data of the simulations conducted by the author's group.

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Heat and Moisture Transport by Local Circulations

Numerical Simulation

Fujio KIMURA

1995 Volume 14 Issue 6 Pages 427-433
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.427

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Outline of numerical models for local circulation is shown, and then fundamental characteristics of local circulations over complex terrain are discussed with the results of numerical simulation of thermally-induced local circulation over a periodic valley. Some findings by a linear model and a three-dimensional numerical model applied to Kanto-Chubu area are also shown.
During the daytime of clear calm days, heat is transported from the mountainous region to the valley area by up-slope winds and the return flows. The specific humidity is, however, transported in an inverse manner. The horizontal exchange rate of sensible heat has a similarity on the horizontal scale of the topography, as long as it is less than a critical width of about 100 km.

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Stokes Flow Induced by Uniform Shear Stress Acting on the Free Surface of a Fluid with a Uniformly Varying Depth

Nobuhiro MATSUNAGA, Yasufumi SUZUKI, Hiroyuki HONJI

1995 Volume 14 Issue 6 Pages 434-437
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.434

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A creeping viscous flow has been visualized in the case when uniform shear stress acts on the free surface of a highly viscous fluid on a sloping bed. The velocity profiles have been obtained from the visualized flow patterns. The flow has been analyzed theoretically under the Stokes approximation. A good agreement has been seen between the experimental and theoretical results.

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Interaction of a Vortex with a Reflected Shock Wave

Nobumi SAIDA, Isao MISU, Shigeki OKAI

1995 Volume 14 Issue 6 Pages 438-444
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.438

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This paper presents experimental and numerical studies of two-dimensional shock impinging at right angles to the vortex path. The experiments were carried out in a conventional shock tube having a cross section of 120 × 60 mm² with initial pressure ratio of 10 in air. The vortex was generated by the diffraction of the incident shock around the convex corner. Optical measurements were used for recording the reflected shock and details of the flow field behind shock waves. A numerical simulation was also conducted using the TVD second order explicit method of MacCormack applied to the Euler equations. It was found that as the reflected shock passes through the vortex, it splits into two parts and behind the accelerated shock a cylindrical sound wave is produced which encloses the vortex. Furthermore, calculated density agrees fairly well with the experimental result.

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Coherent Structure in Narrow Rectangular Open Channels

Hisao NAGABAYASHI, Kiyoji KIMURA

1995 Volume 14 Issue 6 Pages 445-458
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.445

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Three kinds of flow visualization technique have been used to determine the average characteristics of coherent structure in narrow rectangular open channels. The results indicate that some aspects of streamwise vortices, respect to pattern of existence, behavior, and formation. The concentrated region of streamwise vortices is dominated by width-to-depth ratio, b/h, and wall roughness. A mechanism for the formation of low speed region of the flow field is explained by the motion of the streamwise vortices.

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[title in Japanese]

[in Japanese]

1995 Volume 14 Issue 6 Pages 459-467
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.459

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[title in Japanese]

[in Japanese], [in Japanese]

1995 Volume 14 Issue 6 Pages 468-471
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.468

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[title in Japanese]

[in Japanese], [in Japanese]

1995 Volume 14 Issue 6 Pages 472-473
Published: December 31, 1995
Released on J-STAGE: March 07, 2011

DOIhttps://doi.org/10.11426/nagare1982.14.472

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