MURAI Motohiko

Organization

Faculty of Environment and Information Sciences, Division of Artificial Environment and Information

Title

Associate Professor

Date of Birth

1970

Research Fields, Keywords

Very Large Floating Structure, Mega-float, Offshore structure, Offshore environment, Hydroelasticity, Hydrauric test, Uminokouen, Tidalland, Shell-digging, Human-activity in coastal zone, Utilization of Ocean Energy, Marine Renewable Energy, Ocean Renewable Energy

Mail Address

E-mail address



The Best Research Acheivement as Researcher Life 【 display / non-display

  • 【Published Thesis】 On the hydroelastic responses of a very large floating structure in waves  1999.12

    【Published Thesis】 Experimental and theoretical analysis of the wave decay along a long array of vertical cylinders  2002.04

Graduating School 【 display / non-display

  •  
    -
    1993.03

    The University of Tokyo   Faculty of Engineering   Graduated

Graduate School 【 display / non-display

  •  
    -
    1995.03

    The University of Tokyo  Graduate School, Division of Engineering  Navalarchtects and Ocean engineerings  Master Course  Completed

Degree 【 display / non-display

  • Doctor of Engineering -  The University of Tokyo

External Career 【 display / non-display

  • 1997.08
    -
    1999.03

    Reserch Associate, University of Tokyo Faculty of Engineering Department of Naval Architecture and Ocean Engineering   Research Assistant  

Academic Society Affiliations 【 display / non-display

  • 2011.07
     
     
     

    Japanese Association for Coastal Zone Studies

Field of expertise (Grants-in-aid for Scientific Research classification) 【 display / non-display

  • Ocean environmental engineering

  • Hydromecanics

  • Ocean engineering

  • Naval and maritime engineering

 

Research Career 【 display / non-display

  • A Study of a ocean space utilization

    Project Year:  -   

  • Evaluation of Ocean Environment at Artificial tideland cosidering with human impacts

    Project Year:  -   

  • Development of experiment methods on a very large floating structure in a very small water tank

    Project Year:  -   

  • A Study on Hydroelastic behaviour of a Very Large Floating Structure

    Project Year:  -   

  • Renewable energy in Ocean

    Project Year:  -   

Books 【 display / non-display

  • Ship Geometry and Fundamentals of Hydrostatics (Naval Architecture and Ocean Engineering Series 1)

    Ikeda Yoshiho, Yoshitaka Furukawa, Toru Katayama, Tokihiro Katsui, Motohiko Murai, Satoru Yamaguchi (Part: Joint Work )

    成山堂書店  2018.08 ISBN: 9784425714360

  • Environmental Management of Marine Ecosystems

    Md. Nazrul Islam, Sven Erik Jorgensen (Part: Joint Work , Range: Inclusive Impact Index 'TripleI' )

    CRC Press  2018.03 ISBN: 9781498767729

     View Summary

    https://www.crcpress.com/Environmental-Management-of-Marine-Ecosystems/Islam-Jorgensen/p/book/9781498767729

Thesis for a degree 【 display / non-display

  • 超大型浮体の波浪中流力弾性挙動の推定法に関する研究

    村井基彦 

      1999.01  [Refereed]

    No Setting   Single Work

  • 応答制御を用いた大水深ライザーのエントリー/リエントリー

    宇佐美陽生, 村井基彦 

      1993.03  [Refereed]

    No Setting   Joint Work

Papers 【 display / non-display

  • STUDY ON THE GENERATED POWER CHANGES BY THE RELATION BETWEEN AN ARRANGEMENT OF AN ARRAY OF POINT ABSORBER TYPE WECS AND AN INCIDENT WAVE ANGLE

    Motohiko Murai, Li. Qiao, Junki Funada

    Proc of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering OMAE2018 ( ASME )  OMAE2019   95400   2019.06  [Refereed]

    Joint Work

     View Summary

    Using marine renewable energy can contribute providing the energy instead of using fossil fuel. There are some types of marine renewable energy. Wave energy is one of these and no one doubts its vast potential once they glance the sea. The object of this paper is an array of Point Absorber Wave Energy Converters (PA-WECs). In the array, complex hydrodynamic interactions among the array will occur. The interaction influences the wave power density among the array both increase and decrease. When we consider the maximization of generated electric power of the array, the suitable choice of the control force of the generator taken into a positive effect of the hydrodynamic interactions is the key. In the past research, as for a detection of the suitable control force of a single PA-WEC it has been shown the analytical solution within linear system. In this paper, we show the numerical solution of the control force parameter for maximizing the generated electric power of the array taking the hydrodynamic interaction among the array both in diffraction and radiation problem into account. Then we carried out the numerical examination and discussed the good arrangement of an array in waves based on the proposed method and an effect of the choice of the best and better control force.

  • CONTROL STRATEGY FOR A POINT-ABSORBER WAVE ENERGY CONVERTER

    Li. Qiao, M.Murai

    Proc of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering OMAE2018 ( ASME )  OMAE2019   95836   2019.06  [Refereed]

    Joint Work

     View Summary

    Linear driving wave energy converter (WEC) system need to control the electric generator to obtain more power generation. Electric power is consumed by control, but it is possible to control the natural period of the floating motion. By resonating the movement of the float part with wave, it is possible to obtain the power generation more than the control power consumption, the total power generation performance will be improved. In this study, to ensure the WEC safety and performance for various wave condition, especially high wave height, the electrical control algorithms are changed for different wave condition. A control strategy is proposed for various wave condition considering the control force limitation and motion amplitude limitation. Basis on the control strategy, the range of operation by electric control is estimated. In addition, by estimating the expected value of power generation in the set sea, the setting parameters of the WEC can be discussed according to the wave situation.

  • ENVIRONMENTAL REGENERATION FOR A SMALL-SCALE BEACH “HEDA-MIHAMA PROJECT”

    Shigeru Tabeta, Ken Okamoto, Takayoshi Kato, Rikito Hisamatsu, Hiroaki Muto, Akinori Hino, Motohiko Murai, Sho Ito, Daisuke Kitazawa, Takeshi Kinoshita

    Proc of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering OMAE2018 ( ASME )  OMAE2019   95596   2019.06  [Refereed]

    Joint Work

     View Summary

    In 1950’s and 1960’s, Mihama beach in Heda Bay located on western coast of Izu peninsular had been famous for the richness in shell fauna, for example, about 400 species including rare ones were collected. In 2000’s, however, the impoverishment of ecosystem function has become considerable, which led us to project the investigation on the origin and restoration. The authors carried out field survey in 2007-2008 and found that the impoverishment of Mihama is derived not from surface water but from the benthic environment. The suitability indices (SI) for each environmental factors were calculated by using the results of hydrodynamic and sediment transport simulations. By using the developed scheme, total habitat unit was evaluated for the proposed regeneration plans and compared to that without countermeasures. It was predicted that the removal of the piers will improve the habitat condition in the target site. Based on the proposal by the authors, a water pathway under the pier was built in 2009. The authors conducted field survey again in 2014 and confirmed that the benthic environment has been improved.

  • EXPERIMENTAL STUDY ON BUBBLE SIZE MEASUREMENT FOR DEVELOPMENT OF SEAFLOOR MASSIVE SULFIDES

    S.Imai, Y. Nakajima, M.Murai

    Proc of the ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering OMAE2018 ( ASME )  OMAE2019   95186   2019.06  [Refereed]

    Joint Work

     View Summary

    Seafloor Massive Sulfides have been expected to be future mineral resources. To promote the development of Seafloor Massive Sulfides, Seafloor Mineral Processing, a method of extracting valuable minerals from the ores on deep seafloor using flotation to reduce the lifting cost of ores from the seafloor to the sea surface, was proposed. Bubble size measurement by image analysis was carried out by the procedure established at the first phase. While the process of bubble generation at the high pressures was similar to that at the atmospheric pressure, the bubble size was decreased as the pressure rose. The result implies there is a strong correlation between the pressure and the bubble size.

  • SThe Basic Study oSlam Forces Acting on External Turrets -The Effect of Deadrise Angle-

    Y. Ishihara, S. Kato, K.Yukawa, M.Murai

    Proc. of annual conference of JASNAOE ( JASNAOE )  28   351 - 356   2019.05

    Joint Work

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Works 【 display / non-display

  • Muti-arrays supported very large floating Structure

    Other 

    2000
     
     
     

Grant-in-Aid for Scientific Research 【 display / non-display

  • Grant-in-Aid for Scientific Research(C)

    Project Year: 2018.04  -  2021.03  Investigator(s): Motohiko MURAI

  • Grant-in-Aid for Scientific Research(C)

    Project Year: 2013.04  -  2016.03  Investigator(s): Motohiko Murai

  • Grant-in-Aid for Scientific Research(B)

    Project Year: 2012.04  -  2016.03  Investigator(s): Makoto Arai

  • Grant-in-Aid for Scientific Research(B)

    Project Year: 2008.04  -  2011.03 

  • Grant-in-Aid for Scientific Research(B)

    Project Year: 2008.04  -  2011.03 

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Presentations 【 display / non-display

  • ocean renewable energy

    APhydro2012  2012.09.04  

  • Ocean renewable energy

    Oceans2012  2012.05.22  

  • Ocean space utilozation

    2011.08  

  • Ocean space utilozation

    2011.08  

  • Ocean space utilization

    2011.05.18  

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Council/Academic activity outside the university 【 display / non-display

  • ISSC Specialist Committee on Ocean Space Utilization

    2018.09
     
     

    Society   member

  • IEC(International Electrotechnical Commission) TC-114(Marine energy - Wave, tidal and other water current converters) PT 62600-202

    2015.02
     
     

    Others   member

  • ITTC Specialist Committee on Testing of Marine Renewable Devices

    2011.09
    -
    2017.09

    Others   Member

Social Contribution(Extension lecture) 【 display / non-display

  • World NAOE Forum 2013 &International Symposium on Developments in Marine and Offshore Renewable Energy

    2013.11