NAITOH Takashi

写真a

Affiliation Department

Department of Physical Science and Engineering
Department of Physical Science and Engineering

Title

Associate Professor

External Link

Degree

  • Master of Engineering ( Nagoya Institute of Technology )

  • Doctor (Engineering) ( Nagoya Institute of Technology )

Research Areas

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Fluid engineering

From Graduate School

  • Nagoya Institute of Technology   Graduate School, Division of Engineering   Master's Course   Completed

    - 1991.03

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    Country:Japan

External Career

  • 日本ユニシス株式会社   -

    1991.04 - 1992.03

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    Country:Japan

 

Research Career

  • Study on Mass Transport using Vortex Rings

    (not selected)  

    Project Year:

Papers

  • On the evolution of vortex rings with swirl Reviewed

    Takashi Naitoh, Nobuyuki Okura, Toshiyuki Gotoh, Yusuke Kato

    Physics of Fluids   26 ( 6 )   067101   2014.06

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4882683

  • Mass transport using the series of vortex rings with swirl Reviewed

    Takashi NAITOH, Nobuyuki OKURA, Osamu SUMITOMO

    Journal of Fluid Science and Technology   9 ( 3 )   JFST0060   2014.09

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1299/jfst.2014jfst0060

  • Experimental formation of vortex rings with swirl by using a short rotating nozzle Reviewed

    Takashi NAITOH, Takuro ISHIHARA, Ryoga ITO

    Proceedings of the 7th International Conference on Jets, Wakes and Separated Flows   2022.03

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    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)  

  • Transition patterns of negatively buoyant vortex rings Reviewed

    Takashi NAITOH, Tomomi TANAKA

    Proc. of the 11th Pacific Symposium on Flow Visualization and Image Processing   2017.12

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    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)  

    We experimentally observed the formation and development of the negatively buoyant vortex rings which are formed by pushing lighter fluid vertically downward. In this case, the buoyancy force and momentum flux are opposed. We targeted at the negatively buoyant vortex rings in the wide range of Reynolds number and Froude number, 3,600 ≤ ReUjmax ≤ 22,000 and 0.4 ≤ Fr ≤ 14.4, and dealt with making a map of flow development patterns of the rings by means of planer laser-induced fluorescence technique. Buoyant vortex ring development patterns are classified into five types including three types of transition patterns to be turbulent and revealed the Reynolds number range in which the negatively buoyant vortex ring becomes turbulent in relation to the Froude number.

  • Penetration by a Negatively Buoyant Vortex Ring Reviewed International journal

    Takashi NAITOH, Nobuyuki OKURA et al.

    Proceedings of the 5th International Conference on Jets, Wakes and Separated Flows (ICJWSF2015)   565 - 570   2016

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    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Springer International Publishing  

    In order to investigate the vortex motion affected by buoyancy force, we experimentally formed a negatively buoyant vortex ring by pushing less dense fluid vertically downward out of a nozzle and measured the penetration depth of it in the wide Reynolds number range, 3,000 < Re < 30,000. We confirmed that the penetration depth of negatively buoyant vortex rings generally depends only on the Froude number and it is larger than that of the jet for the same Froude number in the range of Fr > 2. The formation conditions of buoyant vortex rings to be turbulent or laminar are also examined, since the characteristic features of buoyant turbulent vortex rings are markedly different from those of buoyant laminar rings.

    DOI: 10.1007/978-3-319-30602-5

  • Characteristics of Mass Transport by a Vortex Ring Reviewed

    31 ( 2 )   187 - 194   2012.04

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  • Quantitative Measurement of Mass Transport Using Vortex Rings Reviewed

    Takashi NAITOH, Nobuyuki OKURA, Muneshige OKUDE and Yusuke UTSUMI

    TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B   77 ( 775 )   557 - 567   2011.03

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    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    Other Link: http://www.jstage.jst.go.jp/article/kikaib/77/775/77_557/_article/-char/ja/

  • 回転環状水槽内に現れる渦構造 Reviewed

    大藏信之 内藤隆 奥出宗重

    ながれ   28   65 - 73   2009.02

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  • Scaling and instability of a junction vortex Reviewed

    J.J.Allen T.Naitoh

    Journal of Fluid Mechanics   574   1 - 23   2007.02

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    Language:English   Publishing type:Research paper (scientific journal)  

  • Experimental study of the production of vortex ring Reviewed

    J.J.Allen T.Naitoh

    Physics of Fluids(Letter)   17 ( 6 )   061701 - 1   2005.04

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    Language:English   Publishing type:Research paper (scientific journal)  

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Presentations

  • Conditions of air ejection to form bubble rings

    Seiya Asai, Ryota Takekawa, Takashi Naitoh

    2023.11 

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    Event date: 2023.11

    Language:Japanese   Presentation type:Oral presentation (general)  

  • The circumferential velocity distribution and the angular momentum of vortex rings generated from a rotating nozzle

    Ryoga Ito, Takashi Naitoh, Takuro Ishihara

    Japan Society of Fluid Mechanics Annual Meeting 2023  2023.09  The Japan Society of Fluid Mechanics

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    Event date: 2023.09

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:Tokyo University of Agriculture and Technology Koganei Campus  

  • 中空渦輪の形成

    笠松大暉,内藤隆

    第20回 日本流体力学会中部支部講演会  2022.12  日本流体力学会中部支部

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    Event date: 2022.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:福井県福井市手⼿寄 1-4-1 アオッサ  

  • The swirl distribution of vortex rings generated from a rotating nozzle whose length is shorter than that of the jet slug

    2022.09 

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    Event date: 2022.09

    Language:Japanese   Presentation type:Oral presentation (general)  

  • Formation conditions of vortex rings with swirl from a rotating cylinder and the distribution of swirling flow

    Takashi NAITOH, Hideyori SHIRAKI, Takuro ISHIHARA

    The Japan Society of Fluid Mechanics Annual Meeting 2021  Japan Society of Fluid Mechanics

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    Event date: 2021.09

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Institute of Industrial Science, The University of Tokyo (online)  

    The vortex rings with swirl are experimentally produced by using a short ejection of fluid from a rotating cylinder. We observed the swirling flow distribution in the meridional plane of vortex rings depending on the formation conditions: angular velocities of the rotating cylinder, rotating duration of the cylinder, timing for stopping operation of rotating cylinders, and two types of rotating cylinder whose length are 300 mm and 40 mm. Therefore, we found that the azimuthal velocity distribution is concentrated around the core of vortex ring and the maximum value of the azimuthal velocity is about proportional to the angular velocity and the square root of rotating duration of the cylinder under the condition that the rotating duration is short.

  • Low density fluid vortex rings moving vertically downward and swirling effect

    Takashi NAITOH, Yoshihiko MAKINO

    Annual Meeting 2020  Japan Society of Fluid Mechanics

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    Event date: 2020.09

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:Tokiwa Campus, Yamaguchi University  

    Low density fluid vortex rings moving vertically downward are produced from three types of nozzle which have curved blades or helical groovings to supply azimuthal velocity component along the vortex line hereinafter referred to swirl. The propagation distance and the velocity variations of these rings are compared with those of rings without swirl. It was found that the propagation distance of negatively buoyant vortex rings can be increased due to swirl in the range of large Froude number similar to non-buoyant vortex rings. As the Froude number decreases, the turbulent intensity increases because of Rayleigh-Taylor instability and the difference of the propagation distance of vortex rings between with swirl and without swirl becomes smaller.

  • Translational velocity of negatively buoyant vortex rings International conference

    Takashi NAITOH, Fumiya AOKI

    JSME the 97th Fluids Engineering Division Conference  The Japan Society of Mechanical Engineers

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    Event date: 2019.11

    Language:Japanese   Presentation type:Poster presentation  

    Venue:Hotel Associa Toyohashi  

  • Turbulent transition of vortex rings with swirl formed from nozzles with blade

    Takashi NAITOH, Hajime GOSHIMA

    The Japan Society of Fluid Mechanics Annual Meeting 2019  The Japan Society of Fluid Mechanics

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    Event date: 2019.09

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:The University of Electro-Communications  

  • Vortex rings formed from nozzle attached with curved deflecting blades

    Hajime GOSHIMA, Takashi NAITOH

    The 16th conference of JSFM Chubu branch  The Japan Society of Fluid Mechanics, Chubu branch

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    Event date: 2018.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:Shizuoka University Hamamatsu Campus  

  • Vortex motion affected by negatively buoyant force

    Fumiya AOKI, Takashi NAITOH

    Japan Society of Fluid Mechanics Annual Meeting 2018  The Japan Society of Fluid Mechanics

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    Event date: 2018.09

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:Osaka University Toyonaka Campus  

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Awards

  • Award for Excellent Visualized Image (Technical Section)

    1997.04  

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    Country:Japan

Scientific Research Funds Acquisition Results

  • 軸流による渦輪の制御

    2009.04 - 2013.03

    科学研究費補助金  基盤研究(C)

    内藤隆

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    軸流を渦輪に導入することにより,渦輪の乱流遷移または急激な渦構造の崩壊を抑制することができた.しかしながら,軸流成分が大きくなると,Peeling off と呼ぶ渦放出現象が顕著になり,循環が低下することも分かった.その原因となるHead & Tail 構造形成のメカニズムを解明した.

  • 境界層剥離の抑制制御を目的とした渦輪生成パラメータの最適化

    2003.04 - 2006.03

    科学研究費補助金  若手研究(B)

    内藤隆

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    Synthetic jet の形成パラメータが詳細に調査され,バックステップの剥離流れへの適用が試みられた。また,渦輪による流れの制御の可能性が明らかにされた.

  • 渦輪の周方向に現れる不安定波の形状について

    1997.04 - 1999.03

    科学研究費補助金  奨励研究

    内藤隆

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    渦輪の波状変形の過程とレイノルズ依存性が詳細に報告された。これによって,渦輪の乱流遷移の過程が明らかにされ,渦輪の制御,またそれをおしすすめて流れの制御についての仕組みが理解された.