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Affiliation Department |
物理工学科 応用物理分野
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Title |
Associate Professor |
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External Link |
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NAITOH Takashi
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Degree
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Master of Engineering ( Nagoya Institute of Technology )
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Doctor (Engineering) ( Nagoya Institute of Technology )
Research Areas
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Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Fluid engineering
From Graduate School
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Nagoya Institute of Technology Graduate School, Division of Engineering Master's Course Completed
- 1991.03
Country：Japan
Research Career
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Study on Mass Transport using Vortex Rings
(not selected)
Project Year：
Papers
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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
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
DOI： 10.1063/1.4882683
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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
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)
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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
Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)
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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
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.
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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
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.
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Characteristics of Mass Transport by a Vortex Ring Reviewed
31 ( 2 ) 187 - 194 2012.04
Language：Japanese Publishing type：Research paper (scientific journal)
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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
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/
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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
Language：Japanese Publishing type：Research paper (scientific journal)
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Scaling and instability of a junction vortex Reviewed
J.J.Allen T.Naitoh
Journal of Fluid Mechanics 574 1 - 23 2007.02
Language：English Publishing type：Research paper (scientific journal)
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Experimental study of the production of vortex ring Reviewed
J.J.Allen T.Naitoh
Physics of Fluids(Letter) 17 ( 6 ) 061701 - 1 2005.04
Language：English Publishing type：Research paper (scientific journal)
Presentations
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The effect of inlet geometries on fluid transport in the motion of a negatively buoyant vortex ring
Emon MAEDA, Takashi NAITOH
Japan Society of Fluid Mechanics Annual Meeting 2024 2024.09 The Japan Society of Fluid Mechanics
Event date： 2024.09
Language：Japanese Presentation type：Oral presentation (general)
Country：Japan
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Air ejection conditions and circulation for forming bubble rings
Ryota TAKEKAWA, Takashi NAITOH
Japan Society of Fluid Mechanics Annual Meeting 2024 2024.09 The Japan Society of Fluid Mechanics
Event date： 2024.09
Language：Japanese Presentation type：Oral presentation (general)
Country：Japan
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Conditions of air ejection to form bubble rings
Seiya Asai, Ryota Takekawa, Takashi Naitoh
2023.11
Event date： 2023.11
Language：Japanese Presentation type：Oral presentation (general)
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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
Event date： 2023.09
Language：Japanese Presentation type：Oral presentation (general)
Venue：Tokyo University of Agriculture and Technology Koganei Campus
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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
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
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The swirl distribution of vortex rings generated from a rotating nozzle whose length is shorter than that of the jet slug
2022.09
Event date： 2022.09
Language：Japanese Presentation type：Oral presentation (general)
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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
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.
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Low density fluid vortex rings moving vertically downward and swirling effect
Takashi NAITOH, Yoshihiko MAKINO
Annual Meeting 2020 Japan Society of Fluid Mechanics
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.
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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
Event date： 2019.11
Language：Japanese Presentation type：Poster presentation
Venue：Hotel Associa Toyohashi
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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
Event date： 2019.09
Language：Japanese Presentation type：Oral presentation (general)
Venue：The University of Electro-Communications
Awards
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Award for Excellent Visualized Image (Technical Section)
1997.04
Country：Japan
Scientific Research Funds Acquisition Results
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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
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．
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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
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．
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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
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．