Papers - Sawada, Tatsuo

Dynamic pressure change of a liquid sloshing in a rotating, laterally oscillating, cylindrical container

Tatsuo Sawada, Eisaku Yokose and Yusuke Saito

CD-Proceedings of 2018 Sustainable Industrial Processing Summit and Exhibition 4   101-108 2019.06

Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  2291-1227

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We investigated characteristics of water sloshing in a rotating, laterally oscillating, cylindrical container both theoretically and experimentally. In our experiment, the time-dependent dynamic pressure of the water on the wall rather than the free-surface displacement of the water was measured, and the experimental parameters are the lateral forcing frequency, the rotation frequency of the cylindrical container, and the water depth. We also conducted a theoretical analysis to understand the experimental results. The swirling of water in the container had some frequency components; the frequency responses of each frequency component are examined herein.

Application of knockdown pontoons of the emergency measures for volcanic hazards of Mount Fuji

Yuji Doya, Tatsuo Sawada, Taisuke Morikawa, Yuya Iseda

Journal of Fujiology (Japan Society of Fujiology)  15 ( 2 ) 1 - 15 2019.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2433-0310

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We investigate the stability and strength of a reinforced, rectangular-hull knockdown pontoon to determine the feasibility of the usage of knockdown pontoons for emergency procedures in case of Mt. Fuji volcanic hazards. The stability of the self-propelled ship is evaluated by the metacentric height of the ship. However, a pontoon with a rectangular hull exhibits a large metacentric height that could cause the loss of ship stability. We propose a new technique to avoid an overly optimistic evaluation of a pontoon’s stability. The hull strength evaluation method that is used in case of the reinforced knockdown pontoon differentiates between two types of load distributions, divided load and concentrated load. By comparing the evaluations that were obtained using these two types of load distribution, we clarified the differences between these approaches.


Magnetic fluid flow under DC and AC magnetic fields

Yuta Itahashi, Ryutaro Hirano and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  59 ( 1 ) 341 - 347 2019.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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This study reports magnetic fluid flow in a square duct under DC, AC, and DC+AC magnetic fields. We measured pressure drop with applying different magnetic fields. Under magnetic fields, flow resistance increased by forming a cluster so that pressure drop and friction factor also increased. From FFT analysis of the pressure drop, we obtained different power spectrum for AC and DC+AC magnetic fields.

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Change of ultrasonic propagation velocity in MR fluid under AC magnetic fields

Takashi Fukumoto, Yuya Tanaka and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  59 ( 1 ) 335 - 340 2019.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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This paper reports the experimental studies on a magneto-rheological (MR) fluid under AC magnetic fields. Magnetic clusters in the MR fluid are formed along the magnetic fields. The ultrasonic propagation velocity changes owing to the presence of clustering structures in the MR fluid. We investigated clustering structures by measuring this change in the ultrasonic propagation velocity. The results indicate that magnetic clusters in the MR fluid depend on the elapsed time, intensity, frequency, and angle of the AC magnetic fields.

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Frequency response of a liquid sloshing in a rotating, laterally oscillating, cylindrical vessel

Eisaku Yokose, Yusuke Saito and Tatsuo Sawada

MATEC Web of Conferences (EDP Sciences)  211   15003(6pp) 2018.10

Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  2261-236X

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We have investigated the free-surface fluctuations of liquid in a rotating, laterally oscillating, cylindrical vessel. We measured the time-dependent fluid-dynamic pressure instead of the free surface luctuations. From an FFT analysis of the dynamic pressure, we obtained two significant frequencies. They are associated, respectively, with waves that rotate in the same direction, and in the opposite direction, relative to the rotation of the vessel. We also examined these results using linearized wave theory.

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Dynamic pressure change in a rotating, laterally oscillating cylindrical container

Yusuke Saito and Tatsuo Sawada

Journal of Ocean Engineering and Science (Elsevier)  3 ( 2 ) 91 - 95 2018.05

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2468-0133

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We examined wave phenomena pertinent to water in a rotating, laterally oscillating cylindrical container. In particular, we measured the time-dependent dynamic water pressure and pressure change by fast Fourier transform analysis. The swirling of water in the container had three frequency components; the frequency responses of each frequency component are reported herein. When swirling occurs in a rotating cylindrical container, it was found that the wave rotating in the same direction as the rotation of the cylindrical container and the wave rotating in the opposite direction to the cylindrical container exist at the same time.

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Changes in the resistance force of a magneto-rheological shock absorber induced by a magnetic field

Tatsuo Sawada, Takuma Endo, Yuzo Shimizu and Hitoshi Nishida

Materials Science Forum (Trans Tech Publications, Switzerland)  915   39-44 - 44 2018.03

Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  1162-9752

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The magnetic particles in an MR fluid form clusters parallel to the direction of the applied magnetic field, and yield stress is generated. As a result, the apparent viscosity of the MR fluid increases. In the present paper, we propose a theoretical approach for obtaining the resistance force controlled by the magnetic field using an MR flow model. We use a mechanical model of an MR fluid pipe flow with a tapered pin. Moreover, we conduct some experiments to test our theoretical approach.

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Liquid sloshing in a rotating, laterally oscillating cylindrical container

Yusuke Saito and Tatsuo Sawada

Universal Journal of Mechanical Engineering (Horizon Research Publishing)  5 ( 3 ) 97 - 101 2017.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2332-3361

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Free surface movement of water in a rotating, laterally oscillating cylindrical container was qualitatively investigated. The swirling direction was determined by forcing the frequency and rotating direction of the cylindrical container. The swirling direction was opposite to that of the rotating cylindrical container when the forcing frequency was low, whereas the crest of the free surface swirled in the same direction as that of the rotating cylindrical container when the forcing frequency greatly increased. Unstable swirling occurred when swirling direction changes, but it disappeared as the rotating frequency increased.

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Suppression of heat transfer of turbulent magnetic fluid flow by applying uniform magnetic field

Masaaki Motozawa, Kosuke Takeda, Yasuo Kawaguchi, Tatsuo Sawada and Mitsuhiro Fukuta

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  52 ( 1-2 ) 113 - 120 2016.12

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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Forced convective heat transfer of turbulent magnetic fluid flow is remarkably suppressed by applying magnetic field. Detailed investigation of this suppression of turbulent heat transfer of magnetic fluid was carried out experimentally in this study. The result shows that the suppression of heat transfer becomes strong by applying stronger magnetic field, but is saturated at a certain strength of magnetic field. This suppression depends on not only magnetic field intensity but also flow condition. For generalization of the suppressed heat transfer characteristics of turbulent magnetic fluid flow by applying magnetic field, we proposed Mh number which is defined by Re divided by a root of magnetic field intensity normalized by saturated magnetization of magnetic fluid. It is found that suppressed heat transfer of magnetic fluid almost linearly increases with increasing Mh number.

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Effect of a tapered metering pin on magnetorheological fluid under an impact load

Yuzo Shimizu, Takuma Endo, Shintaro Takagi and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  52 ( 3-4 ) 1393 - 1400 2016.12

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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We proposed a mechanical model of MR fluid pipe flow and compared with the experiment results of the flow under an impact load, and conducted drop impact tests with four types of tapered metering pins and qualitative analysis of effects of the pins. The results show that the shape of the pins has some effect on the entire shock absorption process whereas magnetic field strength affects the post-peak behavior only, and shock absorption with a longer tapered pin is more widely controllable by magnetic field.

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Effect of tapered metering pin on magnetorheological fluid subjected to shock loading

Yuzo Shimizu, Shintaro Takagi and Tatsuo Sawada

Materials Science Forum (Trans Tech Publications, Switzerland)  856   3 - 8 2016.05

Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  0255-5476

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Using four types of tapered metering pins, we conducted drop impact tests and a qualitative analysis of effects of the pins on MR fluid with a magnetic field applied around an orifice area. The tapered metering pins changed the piston stroke. The results indicate that the shape of the pins has some effect on the overall shock absorption process whereas magnetic field strength affects the post-peak behavior only. These results show that a tapered metering pin has applicability to shock absorbers using an MR fluid.

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Vibrating properties of magnetic fluid tuned liquid column damper with different U-pipes

Shinya Kondo, Kazuki Ikari and Tatsuo Sawada

Materials Science Forum (Trans Tech Publications, Switzerland)  856   21 - 25 2016.05

Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  0255-5476

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We performed vibration experiments for three types of U-pipes, and obtained the following results: (1) The shape of the bottom and elbow of the U-pipe has no influence on the natural frequency change of an MF-TLCD (Magnetic-Fluid Tuned Liquid Column Damper) when a magnetic field is applied. (2) When using a U-pipe with an elbow with a larger curvature, it is possible to reduce the damping force on the liquid column and improve MF-TLCD performance.

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Effect of magnetic field direction on forced convective heat transfer of magnetic fluid

Masaaki Motozawa，Kyohei Kino, Tatsuo Sawada，Yasuo Kawaguchi, Mitsuhiro Fukuta

Journal of the Japan Society of Applied Electromagnetics and Mechanics (The Japan Society of Applied Electromagnetics and Mechanics)  23 ( 3 ) 612 - 617 2015.09

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0919-4452

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We investigated the forced convective heat transfer of magnetic fluid by applying magnetic field in a vertical, a parallel and an axial direction against heat transfer direction by using a rectangular duct. In the case of laminar flow, heat transfer was enhanced in the vertical direction and slightly enhanced in the axial direction, but hardly changed in the parallel direction. In contrast, in the case of turbulent flow, heat transfer was suppressed in all directions. The suppression level in vertical and parallel direction is similar, but the suppression in axial direction is much weaker than those in other directions.

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The effect to the damping performance of magnetic fluid tuned liquid column damper induced by various damping coefficient of liquid column

Kazuki Ikari, Shinya Kondo, Tatsuo Sawada

Journal of the Japan Society of Applied Electromagnetics and Mechanics (The Japan Society of Applied Electromagnetics and Mechanics)  23 ( 2 ) 368 - 373 2015.06

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0919-4452

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Magnetic fluid tuned liquid column damper (MF-TLCD) is a kind of semi-active damper that uses magnetic fluid as its working fluid. An MF-TLCD alters the natural frequency of the magnetic fluid column that forms the resident liquid inside the MF-TLCD by applying a magnetic field. We quantitatively investigated the damping coefficient generated by the flow of magnetic fluid, which is strongly related to the damping performance. Three kind of U-pipes that have each different shape were prepared and single-degree-of-freedom oscillation was performed with each those pipes. Finally, we discussed the effect to the damping performance of MF-TLCD induced by various damping coefficient subjected to magnetic field and configurations of those U-pipes.

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磁性流体同調液柱管ダンパーの容器形状が液柱振動に及ぼす影響

近藤真也, 碇 一暉, 澤田達男

2014 JSMFR selected proceedings (磁性流体研究連絡会)     28 - 30 2015.01

Research paper (conference, symposium, etc.), Joint Work

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磁性流体同調液柱管ダンパーはU字管内の磁性流体液柱を付加振動系とする制振装置で、磁場印加によって液柱固有振動数の制御が可能である。本研究では異なる三つの形状のU字管容器で加振実験を行い、それぞれの比較検討を行った。2014年12月の磁性流体連合講演会で発表された論文が，査読されて本論文集に掲載された。

Damping characteristics of a magnetic fluid tuned liquid column damper under static magnetic fields

Toshiyuki Oyamada, Hideaki Masuda, Kazuki Ikari and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  45 ( 1-4 ) 659 - 665 2014.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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Magnetic fluid TLCD (MF-TLCD) is a novel type of semi-active damper in which the natural frequency can be controlled by applying magnetic field. We tuned the natural frequency of a column of magnetic fluid to excitation frequency, and demonstrated that the damping performance can improved compared with the case without magnetic field.

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Effect of chamfered orifice inlet on magnetorheological fluid subjected to shock loading

Ahmad Isnikurniawan, Hiromichi Ohba, Hiro Kaneko, Ryo Yoshizawa and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  45 ( 1-4 ) 683 - 688 2014.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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This paper presents an investigation on the effect of chamfered orifice inlet on magnetorheological (MR) fluid subjected to shock loading. Two different orifices (no chamfer and chamfered at 60 degrees angle on the inlet area) are used. The MR fluid is subjected to a shock loading, and the magnetic field is applied on the orifice area. Experiments have been conducted by measuring piston displacement, impact force and pressure difference between the inlet and outlet of the orifice. Based on the experiment result, the effect of chamfered orifice inlet on MR fluid subjected to shock loading is discussed.

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Two-Layer sloshing of magnetic fluid and silicone oil under horizontal magnetic field

Takayoshi Ishiyama, Shunsuke Kaneko, Shin-Ichiro Takemoto and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  45 ( 1-4 ) 675 - 682 2014.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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We carried out experiments on two-layer sloshing using a magnetic fluid and silicon oil, and measured displacements of free surface and interface by a laser sensor. We also carried out theoretical investigation using a linear short-wave theory. We compared with experimental and theoretical results.

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Ultrasonic propagation characteristics of a magnetic fluid under AC magnetic fields

Yasuhiro Fujita, Ahmad Isnikurniawan, Sachio Tanimoto and Tatsuo Sawada

International Journal of Applied Electromagnetics and Mechanics (IOS Press)  45 ( 1-4 ) 667 - 673 2014.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1383-5416

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We conducted experimental studies as the ultrasonic propagation characteristics of a magnetic fluid (MF) under AC magnetic fields. The change rate of sound velocities were related to the formation of clusters in MF and it decreased with increase of AC frequencies.

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Relation between the dynamic pressure and displacement of the free surface in two-layer sloshing with magnetic fluids and silicone oil

Takayoshi Ishiyama, Shunsuke Kaneko, Shin-ichiro Takemoto and Tatsuo Sawada

Materials Science Forum (Trans Tech Publications, Switzerland)  792   33 - 38 2014.08

Research paper (international conference proceedings), Joint Work, Accepted,  ISSN  1662-9752

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We carried out experiments of two-layer sloshing using magnetic fluids and silicone oil, and measured dynamic pressure change by using pressure transducers. We also investigated displacements of free surface. We compared the dynamic pressure with displacements of the free surface and clarified the correlation between them.

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