Presentations -

Characteristics of magnetic and MR fluids flows

Tatsuo Sawada

[International presentation]  The 4th International Conference on Education, Concept, and Application of Green Technology (Semarang) , 

2015.09

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Oral presentation (keynote), Semarang State University

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Keynote lecture about magnetic and MR fluids flows was presented.

Recovery of suppressed turbulent diffusion of magnetic fluid flow in downstream of magnetic field region

Masaaki Motozawa, Kousuke Takeda1, Yasuo Kawaguchi, Tatsuo Sawada and Mitsuhiro Fukuta

[International presentation]  The 9th Japanese-Mediterranean Workshop on Applied Electromagnetic Engineering for Magnetic, Superconducting and Nano Materials (Sofia) , 

2015.07

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Oral presentation (general), Technical University of Sofia

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Streamwise variation of the suppressed turbulent diffusion of magnetic fluid flow in downstream of the magnetic field region was investigated experimentally. Reynolds number based on hydraulic diameter and bulk mean velocity were varied from 6400 to 14300, and magnetic field was applied up to 500 mT. The result shows that the recovery of suppressed heat transfer in downstream of the magnetic field region is strongly related with flow velocity and magnetic field intensity. Distance for recovering the suppressed turbulent diffusion from the magnetic field region becomes shorter in larger Reynolds number flow. The relationship among the recovery distance of the suppressed turbulent diffusion, magnetic body force and inertial force of the flow was discussed.

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

Yuzo Shimizu, Shintaro Takagi and Tatsuo Sawada

[International presentation]  The 9th Japanese-Mediterranean Workshop on Applied Electromagnetic Engineering for Magnetic, Superconducting and Nano Materials (Sofia) , 

2015.07

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Oral presentation (general), Technical University of Sofia

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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.

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

Shinya Kondo, Kazuki Ikari and Tatsuo Sawada

[International presentation]  The 9th Japanese-Mediterranean Workshop on Applied Electromagnetic Engineering for Magnetic, Superconducting and Nano Materials (Sofia) , 

2015.07

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Oral presentation (general), Technical University of Sofia

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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.

Suppression and recovery of forced convective heat transfer in turbulent magnetic fluid flow under magnetic field

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

[Domestic presentation]  The 52th National Heat Transfer Symposium of Japan (Fukuoka) , 

2015.06

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Oral presentation (general), Heat Transfer Society of Japan

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The suppression of turbulent heat transfer and the recovery of the suppressed heat transfer in the downstream of magnetic field region was investigated experimentally in more detail. The result shows that the suppression of heat transfer becomes large by applying stronger magnetic field but is saturated at a certain strength of magnetic field with relation to flow velocity. The recovery of suppressed heat transfer in downstream of the magnetic field region is also related with magnetic field intensity and flow velocity.

Effect of unsteady magnetic fields on pressure drop in a square duct flow of a magnetic fluid

Tatsuo Sawada, Tomohiko Kato and Takehiro Yamamoto

[Domestic presentation]  The 27th Symposium on Electromagnetics and Dynamics (Sasebo) , 

2015.05

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Oral presentation (general), The Institute of Electrical Engineers of Japan

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Pressure drop in a square duct flow of a magnetic fluid was investigated experimentally. DC and AC magnetic fields were applied to the flow. The pressure drop under DC magnetic field was larger than that under the AC magnetic field. When AC magnetic field was applied, the frequency of the pressure drop was twice of that of the AC magnetic field from FFT analysis.

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 and Tatsuo Sawada

[Domestic presentation]  23th MAGDA Conference in Takamatsu (Takamatsu) , 

2014.12

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Poster presentation, The Japan Society of Applied Electromagnetics and Mechanics

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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. 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 ((1) conventional (2) equipped with an orifice (3) curved fluently) 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.

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

[Domestic presentation]  Japanese Symposium on Magnetic Fluids (Tsukuba) , 

2014.11

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Oral presentation (general), 磁性流体研究連絡会

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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。

Effect of a magnetic fluid clusters on a square duct flow

Tomohiko Kato, Yasuhiro Fujita and Tatsuo Sawada

[Domestic presentation]  JSME Fluids Engineering Conference 2014 (Toyama) , 

2014.10

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Oral presentation (general), JSME

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矩形流路内を流れる磁性流体に直流磁場・交流磁場を印加した場合の流動特性を調べた。圧力損失と超音波伝播速度を計測し，磁性体微粒子のクラスタが流れ場に及ぼす影響を調べた。

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

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

[International presentation]  The Eighth Asia Pacific Symposium on Applied Electromagnetics and Mechanics (Taichung) , 

2014.07

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Oral presentation (general), National Chung Hsing University

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We investigated the forced convective heat transfer of a magnetic fluid flow with applying uniform magnetic field in the axial, vertical, and parallel direction in relation to the heat transfer direction.

Flow resistance of a magnetic fluid in a square duct under DC and AC magnetic fields

Tomohiko Kato, Yasuhiro Fujita and Tatsuo Sawada

[International presentation]  14th International Conference on Electrorheological Fluids and Magnetorheological Suspensions (Granada) , 

2014.07

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Poster presentation, University of Granada

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We investigated the cluster formation and the effect of clusters on two-dimension flow in a square duct under DC and AC magnetic fields. We measured the pressure drop in a test section and ultrasonic propagation velocities in order to clarity the influence of DC and AC magnetic fields on flow resistance.

Experimental study on forced convective heat transfer and flow resistance of magnetic fluid flow under non-uniform magnetic field

Masaaki Motozawa, Seiya Tatsuno, Tatsuo Sawada, Yasuo Kawaguchi and Mitsuhiro Fukuta

[International presentation]  The 19th International PAMIR Conference on Fundamental and Applied MHD, Thermo Acoustic and Space Technologies (PAMIR 2014) (Riga) , 

2014.06

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Poster presentation, Laboratoire CNRS-EPM/SIMaP and Institute of Physics, University of Latvia

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Forced convective heat transfer and flow resistance of rectangular duct flow of a magnetic fluid by applying non-uniform magnetic field was investigated experimentally. One characteristic result shows that heat transfer is largely enhanced by applying non-uniform magnetic field in the laminar flow regime. Comparing with the result with applying uniform magnetic field, heat transfer enhancement is larger than that with applying uniform magnetic field. This seems that thermal convection excited by applying non-uniform magnetic field strongly affects the heat transfer.

Characteristics of ultrasonic propagation in magnetorheological fluids under AC magnetic fields

Sachio Tanimoto, Yasuhiro Fujita, Kanta Moriyama and Tatsuo Sawada

[Domestic presentation]  The 26th Symposium on Electromagnetics and Dynamics (Morioka) , 

2014.05

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Oral presentation (general), The Japan Society of Applied Electromagnetics and Mechanics

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This paper presents experimental analysis of magnetorheological fluid (MRF) under alternating magnetic fields. The experiments were conducted under alternating magnetic fields. MRFs of different volume fraction of two types were used in this study. The relation between the change of ultrasonic propagation velocity, the difference of volume fraction and frequency of magnetic field were discussed. As a result, for high volume fraction, the cluster size was affected by frequency of magnetic field rather than for low volume fraction.

Characteristic of ultrasonic propagation in a magnetic functional fluids under AC magnetic fields

Yasuhiro Fujita, Ahmad Isnikurniawan, Sachio Tanimoto, Kanta Moriyama and Tatsuo Sawada

[Domestic presentation]  22th MAGDA Conference in Miyazaki (Miyazaki) , 

2013.12

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Poster presentation, The Japan Society of Applied Electromagnetics and Mechanics

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This paper reports experimental studies about anisotropy and attenuation as characteristics of ultrasonic propagation in a magnetorheological fluid (MRF) under AC magnetic fields. Parameters of this studies are magnitude of AC magnetic fields, frequencies of AC magnetic fields and angles between directions of ultrasonic propagation and magnetic field. As results of change rate of sound velocity, MRF has characteristics of time dependence, frequencies dependence and anisotropy under AC magnetic fields. Also, length of clusters in MRF became short with increase of frequencies of AC magnetic fields. The clusters in MRF are formed along the magnetic force under AC magnetic fields. Attenuation decreased with increase of the angles between directions of ultrasonic propagation and magnetic field. But, attenuation did not change with increase of frequencies of AC magnetic fields.

Influence of non-uniform magnetic field on velocity distribution of rectangular duct flow of a magnetic fluid

Seiya Tatsuno, Masaaki Motozawa, Tatsuo Sawada and Yasuo Kawaguchi

[International presentation]  The 12th International Conference on Fluid Control, Measurements, and Visualization (Nara) , 

2013.11

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Oral presentation (general), The Visualization Society of Japan

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The ultrasonic velocity profiler was used to investigate the influence of non-uniform magnetic field on the velocity distribution of the rectangular duct flow of a magnetic fluid. The results showed that the flow velocity at the upper-leaning side from the center of the duct increased and the velocity gradient at only the bottom wall side, which electromagnet exists, decreased in the laminar flow. In contrast, in the case of turbulent flow, not only velocity gradient but also flow velocity near the center of the duct hardly changed by applying magnetic field. This is because magnetic field intensity is not so strong that the velocity distribution is affected.

Two-layer fluids sloshing under a horizontal magnetic field

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

[International presentation]  The 12th International Conference on Fluid Control, Measurements, and Visualization (Nara) , 

2013.11

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Oral presentation (general), The Visualization Society of Japan

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The effect of magnetic field on two-layer sloshing with magnetic fluids and silicone oil were studied. Frequency-pressure response was recorded to conduct research. The permanent magnets were placed near the interface of two fluids. The resonant frequencies were changed by the positions of the magnets, the type of magnets, and the direction of the magnetic field. This study shows the possibility that two-layer fluid sloshing with magnetic fluids can be controlled by the intensity and the direction of magnetic field.

Damping effect of a tuned magnetic fluid column damper under controlled magnetic field

Toshiyuki Oyamada, Kazuki Ikari, Hiroyasu Nagano and Tatsuo Sawada

[Domestic presentation]  Japanese Symposium on Magnetic Fluids (Toyama) , 

2013.11

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Oral presentation (general), 磁性流体研究連絡会

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現在提案中のセミアクティブ型制振装置である磁性流体液柱管ダンパーの制振特性を検証するため，磁場による固有振動数制御時の制振特性について，構造物-ダンパー系の加振実験を行い，従来型液柱管ダンパーとの比較・検討を行った。

Influence of Magnetic Field Direction on Convective Heat Transfer of Magnetic Fluid Flow

Masaaki MOtozawa, Seiya Tatsuno, Tatsuo Sawada and Yasuo Kawaguchi

[Domestic presentation]  JSME Fluids Engineering Conference 2013 (Fukuoka) , 

2013.11

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Oral presentation (general), JSME

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磁性流体に磁場を印加すると磁場方向に鎖状クラスターが形成され，この形成方向が熱物性に影響を与えることが指摘されている。そこで，本研究では，磁性流体の対流熱伝達へ及ぼす磁場印加方向の影響を調べた。

Frequency response analysis of a tuned magnetic fluid column damper based on a linearized method

Kazuki IKari, Toshiyuki Oyamada and Tatsuo Sawada

[Domestic presentation]  JSME Fluids Engineering Conference 2013 (Fukuoka) , 

2013.11

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Oral presentation (general), JSME

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Frequency response analysis of a tuned liquid column damper using magnetic fluid (MF-TLCD) based on a linearized method was presented. 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. The interaction equations of motion under a harmonic type of loading for SDOF damped structure and liquid surface motion in a MF-TLCD were expressed. The damping term induced by liquid flows and the magnetic force term were linearized to derive analytical solutions. The analytical results were compared with experimental results.

Ultrasonic propagation characteristics of a magnetic fluid under AC magnetic fields

Yasuhiro Fujita, Ahmad Isnikurniawan, Sachio Tanimoto and Tatsuo Sawada

[International presentation]  The 16th International Symposium on Applied Electromagnetics and Mechanics (Quebec) , 

2013.08

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Poster presentation, Université Laval

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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.