Presentations -

Influence of magnetic field on flow resistance of a magneto-rheological fluid damper

Yuta Fukuoka, Kojiro Matsuzaka and Tatsuo Sawada

The 32th Symposium on Electromagnetics and Dynamics (Gifu) , 

2020.05

, 

Oral presentation (general), JSAEM

Application of pendulum theory to a model of the overturning of a rectangular hull in a water tank

Yuji Doya and Tatsuo Sawada

The 11th International Workshop on Ship and Marine Hydrodynamics (Hamburg) , 

2019.09

, 

Oral presentation (general), Hamburg University of Technology

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This paper reports an experimental study of applying pendulum theory to determine whether a rectangular model of a hull would overturn. A pontoon used as a non-self-navigating work vessel was considered in this study. Its model begins to list when an unbalanced load is applied. It can then either stabilize in an inclined state or continue overturning, throwing the unbalanced load midway, and finally stabilizing in the inverted position. In a mid-air experiment, this correlation was made between two motion scenarios, pendular or rotational motion. The two motions were reproduced by changing the distance between the hull center and the rotary axis and the mass of the weight. The experimental results closely matched those of an analytical analysis performed based on the Runge-Kutta method, which confirms the validity of the proposed analysis.

Ultrasonic propagation wave velocity in MR fluid at magnetic field sweep rates

Ryo Kanasashi, Yuya Tanaka, Tatsuo Sawada

The Eleventh Japanese-Mediterranean Workshop on Applied Electromagnetic Engineering for Magnetic, Superconducting, Multifunctional and Nanomaterials (Batumi) , 

2019.07

, 

Poster presentation, Batumi Shota Rustaveli State University

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The ultrasonic wave propagation velocities of MR fluid under DC and AC magnetic fields were examined. Experiments were conducted to investigate the effect of magnetic field sweep rate on the cluster formation in MR fluid.

Self-dumping pontoons for emergency measures during large-scale natural disasters

Yuji Doya, Tatsuo Sawada

The General Meeting of Japan Society of Fujiology (Mishima) , 

2019.07

, 

Oral presentation (general), Japan Society of Fujiology

Ultrasonic propagation characteristics in MR fluid under magnetic fields

Yuya Tanaka, Ryo Kanasashi and Tatsuo Sawada

JSME Fluids Engineering Conference 2018 (Muroran) , 

2018.11

, 

Poster presentation, JSME

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MR fluid is one of the functional fluids affected by the magnetic. When a magnetic field is applied to MR fluid, MR fluid can change its property because of clustering structure. We measure the ultrasonic propagation property through MR fluid under AC magnetic fields. We use two indexes: ultrasonic velocity change rate and attenuation rate. Based on the experimental results, we analyze the clustering structure in MR fluid.

Influence of an applied magnetic field on resistance force of a magneto-rheological fluid in a pipe with a tapered pin

Kojiro Matsuzaka and Tatsuo Sawada

JSME Fluids Engineering Conference 2018 (Muroran) , 

2018.11

, 

Poster presentation, JSME

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We carry out theoretical and experimental study for the resistance force of MR fluid flow in a circular pipe. The purpose of this study is to calculate resistance of MR fluid based on the analysis and to compare the experimental results with the calculated results. The resistance force acting on a cylinder piston with tapered pin depends on the strength of magnetic field, tapered angle, etc. It is proved that the most dominant effect to the resistance force is magnetic field.

Liquid sloshing and swirling in a rotating cylindrical container subjected to horizontal oscillation

Eisaku Yokose, Tatsuki Kaneyoshi and Tatsuo Sawada

JSME Fluids Engineering Conference 2018 (Muroran) , 

2018.11

, 

Poster presentation, JSME

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We investigated the free surface fluctuation of liquid in a rotating cylindrical container which receives horizontal vibration in the horizontal direction. In the experiments, we changed the oscillation frequency f and the rotation frequency. We measured time dependent pressure fluctuation instead of free surface fluctuation. By performing FFT analysis, two significant frequencies are obtained. We also examined these results using linear wave theory.

Ultrasonic wave propagation through mr fluid under AC magnetic field

Yuya Tanaka, Ryo Kanasashi, and Tatsuo Sawada

Japan-Taiwan International Conference on Magnetic Fluids 2018 (Yokohama) , 

2018.11

, 

Poster presentation, Japan Society of Magnetic Fluid Research

Liquid sloshing of rotating and oscillating cylindrical container

Eisaku Yokose, Tatsuki Kaneyoshi, and Tatsuo Sawada

Japan-Taiwan International Conference on Magnetic Fluids 2018 (Yokohama) , 

2018.11

, 

Poster presentation, Japan Society of Magnetic Fluid Research

Deterioration of magnetic fluid seals under liquid contacting conditions

Takayuki Yoshida, Yutaro Takahashi, Ichiro Yamanaka, and Tatsuo Sawada

Japan-Taiwan International Conference on Magnetic Fluids 2018 (Yokohama) , 

2018.11

, 

Poster presentation, Japan Society of Magnetic Fluid Research

Influence of an applied magnetic field on resistance force of a magneto-rheological fluid in a cylinder

Kojiro Matsuzaka, Yuta Fukuoka, and Tatsuo Sawada

Japan-Taiwan International Conference on Magnetic Fluids 2018 (Yokohama) , 

2018.11

, 

Poster presentation, Japan Society of Magnetic Fluid Research

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

Tatsuo Sawada, Eisaku Yokose and Yusuke Saito

2018 Sustainable Industrial Processing Summit and Exhibition (Rio de Janeiro) , 

2018.11

, 

Oral presentation (general), Fondation de la Maison de la Chimie

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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. We 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.

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

Eisaku Yokose, Yusuke Saito and Tatsuo Sawada

14th International Conference on Vibration Engineering and Technology of Machinery (VETOMAC XIV) (Lisbon) , 

2018.09

, 

Poster presentation, International Steering Committee

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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.

Ultrasonic propagation characteristics in MR fluid under magnetic field

Yuya Tanaka, Takashi Fukumoto and Tatsuo Sawada

Asia-Pacific Symposium on Applied Electromagnetics and Mechanics 2018 (Yogyakarta) , 

2018.07

, 

Oral presentation (general), Universitas Gadjah Mada

Resistance force of a magneto-rheological fluid in a pipe with a tapered pin

Kojiro Matsuzaka, Takuma Endo and Tatsuo Sawada

Asia-Pacific Symposium on Applied Electromagnetics and Mechanics 2018 (Yogyakarta) , 

2018.07

, 

Oral presentation (general), Universitas Gadjah Mada

Resistance force of a magneto-rheological fluid on a cylinder piston with a tapered pin

Kojiro Matsuzaka, Takuma Endo and Tatsuo Sawada

The 30th Symposium on Electromagnetics and Dynamics (Nagano) , 

2018.05

, 

Oral presentation (general), IEE

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The resistance force of a magneto-rheological fluid at a cylinder piston with tapered pin in the presence of magnetic field are investigated both experimentally and theoretically. The resistance force at a cylinder piston with tapered pin depends on the strength of magnetic field, tapered pin, etc. It is proved the most dominant effect to the resistance force is magnetic field.

Suggestion about the hull strength evaluation method for the reinforced knockdown pontoon

Yuji Doya, Tatsuo Sawada and Yuya Iseda

The Annual Autumn Meeting of JASNAOE 2017 (Hiroshima) , 

2017.11

, 

Oral presentation (general), The Japan Society of Naval Architects and Ocean Engineers

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組立式台船の強度は，蟻装に使用された機材の重量とその分布，作業時の負荷等の条件を基に，組立式台船の船体同士を連結する連結継手にかかるモーメントとせん断力を算出して，それらの強度が不足する場合は，H鋼等の汎用の構造部材で補強している。実際に補強した船体の強度の評価手法を新たに提案し，両端分割と中央集中の2つの荷重条件について試算した。

Suggestion about indexes of the stability as floating body for a rectangular hull

Yuji Doya, Tatsuo Sawada and Taisuke Morikawa

The Annual Autumn Meeting of JASNAOE 2017 (Hiroshima) , 

2017.11

, 

Oral presentation (general), The Japan Society of Naval Architects and Ocean Engineers

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組立式台船は多種多様な作業船の船体として使用され，その浮体としての安定性については，船体の組立形状，鰭装方法，および，施工時の荷重分布の変化を考慮した乾舷の計算や，施工実績・経験を含めて検討している。ここでは，安定性の指標について，推進器を有する自航船と，推進器を持たない非自航船の特徴を把握し，非自航作業船のような矩形船体の指標について提案を行った。

Experimental and theoretical investigation of liquid sloshing in a rotating, laterally oscillating cylindrical container

Yusuke Saito and Tatsuo Sawada

The 10th International Workshop on Ship and Marine Hydrodynamics (Keelung) , 

2017.11

, 

Oral presentation (general), National Taiwan Ocean University

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We examined wave phenomena pertinent to water in a rotating, laterally oscillating cylindrical container. 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. The swirling direction was determined by the relationship of these magnitude.

Application of the pendulum theory to overturning model of a rectangular hull

Yuji Doya and Tatsuo Sawada

The 10th International Workshop on Ship and Marine Hydrodynamics (Keelung) , 

2017.11

, 

Oral presentation (general), National Taiwan Ocean University

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Knockdown pontoons with rectangular hulls are often used in work vessels during construction. In this paper, we present a novel method of construction that uses knockdown pontoons. The presented method is a self-dumping pontoon system in which the hull is overturned to unload the earth and sand. We model a series of hull movements as a rigid pendulum, thus developing new model equations and solving them by the Runge-Kutta method. Model experiments were also performed, and the calculation results are in agreement with the experiment results. Lastly, we discuss the criteria for hull overturn in detail.