Search Results 1-20 of 2013

  • AIRFLOW AROUND BUILDINGS IN HIGH DENSITY BLOCK OF METROPOLIS:Effects of Reynolds number on airflow between buildings and wind pressure on building walls based on LES  [in Japanese]

    SAJIMA Toshihiko , YAMANAKA Toshio , LIM Eunsu , KOBAYASHI Tomohiro , FUKUYAMA Kanji

    … In urban area in Japanese metropolises, a large number of high-rise buildings are introducing natural ventilation systems, and the way of ensuring stable ventilation performance is very important matter. … In design stage of natural ventilation building, building engineers have to decide the size and number of ventilation devices, such as openings and chimneys or shafts. …

    Journal of Environmental Engineering (Transactions of AIJ) (781), 319-326, 2021-03

    J-STAGE  AIJ 

  • Side-Wall Effects on the Global Stability of Swept and Unswept Supercritical Wings at Buffet Conditions

    SANSICA Andrea , 橋本 敦 , 小池 俊輔 , 河内 俊憲 , SANSICA Andrea , HASHIMOTO Atsushi , KOIKE Shunsuke , KOCHI Toshinori

    流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン (2020年9月28日-30日. 日本航空宇宙学会 : 宇宙航空研究開発機構(JAXA)オンライン会議)形態: カラー図版あり資料番号: AA2030013015レポート番号: JAXA-SP-20-008

    宇宙航空研究開発機構特別資料: 流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン論文集 = JAXA Special Publication: Proceedings of Fluid Dynamics Conference / Aerospace Numerical Simulation Symposium 2020 Online (JAXA-SP-20-008), 109-118, 2021-02-08

    IR 

  • VENTILATION DESIGN METHOD OF BUILDINGS IN DENSE CITY BLOCKS:Effect of length between buildings on airflow and wind pressure based on wind tunnel test  [in Japanese]

    FUKUYAMA Kanji , YAMANAKA Toshio , LIM Eunsu , KOBAYASHI Tomohiro , SAJIMA Toshihiko

    … Designing buildings, it is essential to predict the value of wind pressure coefficient on the building wall and sometimes wind velocity around buildings to calculate air-flow rate through openings accurately. … Total pressure coefficient is considered to be easily evaluated from the flow model based of the loss of total pressure of flow within the channel in blocks. …

    Journal of Environmental Engineering (Transactions of AIJ) 86(783), 526-536, 2021

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  • Modified Reynolds Equations for Thin Film Lubrication with Saturated High-Viscosity Surface Layer and Lubrication Analysis of Tapered Pad Bearing  [in Japanese]

    ONO Kyosuke

    … <p>This paper presents a modified Reynolds equation for analyzing thin film lubrication with a saturated high-viscosity surface layer on a solid surface. …

    JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS, 2021

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  • Influence of Surface Texture on the Performance of Hydrodynamic Journal Bearing Operating under Turbulent Regime

    Awasthi RK , Maan Jagjit Singh

    … <p>Surface texturing may have significant role in tribo-element applications operating at high speed. … The non-dimensional Reynolds equation used for compressible flow is suitably modified for turbulent regime and Finite Element Method has been used to discretise the equation into linear algebraic equation. …

    Tribology Online 16(2), 99-112, 2021

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  • Velocity distribution in the subchannels of a pin bundle with a wrapping wire (Evaluation of the Reynolds number dependence in a three-pin bundle)

    AIZAWA Kosuke , HIYAMA Tomoyuki , NISHIMURA Masahiro , KURIHARA Akikazu , ISHIDA Katsuji

    … <p>A sodium-cooled fast reactor has been designed to attain a high burn-up core in commercialized fast reactor cycle systems. … In high burn-up fuel subassemblies, the fuel pin deformation due to swelling and thermal bowing may decrease the local flow velocity in the subassembly and influence the heat removal capability. … Therefore, understanding the flow field in a wire-wrapped pin bundle is important. …

    Mechanical Engineering Journal, 2021

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  • Effect of flow in the circular 90-degree curved nozzles on ejecting oil jet behavior

    KAWAGUCHI Mikimasa , NITTA Goichi , MIMURA Keita , NISHIDA Keiya , KOUTOKU Masanobu , YAMAMOTO Ryo , NAKASHIMA Akira , OGATA Yoichi

    … Recently, a piston cooling gallery equipped with a flow path has been developed. … We therefore investigated the flow in two nozzles having a basic bend of 90° with radii of curvature of 15 and 60 mm. … Our results clarify the effect of internal flow on the ejecting oil jet behavior. …

    Journal of Fluid Science and Technology 16(2), JFST0011-JFST0011, 2021

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  • Effect of spatial development on convective heat transfer enhancement in a pipe with transverse vibration

    MITSUISHI Akihiko , TAKAHASHI Masahiro , SHIMURA Takaaki , IWAMOTO Kaoru , MURATA Akira

    … <p>The present study models the flow configuration in a tube downstream of multi-branching in a catalytic converter. … The representative Reynolds number is set to be less than that in a driver domain which generates the turbulent inflow of the main domain. … Profiles of the Nusselt number exhibit that the positive effect of the vibration on the heat transfer becomes apparent at certain downstream locations. …

    Journal of Thermal Science and Technology 16(1), JTST0002-JTST0002, 2021

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  • An immersed boundary method for practical simulations of high-Reynolds number flows by <i>k-ε</i> RANS models

    YAO Hiroki , NAMBU Taisuke , MIZOBUCHI Yasuhiro

    … HINOCA is based on fully compressible Navier-Stokes equations, which are Reynolds-averaged (RANS) or spatially-filtered (LES), and employs the Cartesian grid and immersed boundary (IB) methods to reduce the mesh generation cost. … In the present paper, focusing on flow simulations using <i>k-ε</i> …

    Journal of Fluid Science and Technology 16(1), JFST0007-JFST0007, 2021

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  • Suspensions of deformable particles in Poiseuille flows at finite inertia

    Luigi Filippo Chiara , Marco Edoardo Rosti , Francesco Picano , Luca Brandt

    … We analyze a suspension of deformable particles in a pressure-driven flow. … The suspension is composed of neutrally buoyant initially spherical particles and a Newtonian carrier fluid, and the flow is solved by means of direct numerical simulations, using a fully Eulerian method based on a one-continuum formulation. …

    Fluid Dynamics Research 52(6), 065507, 2020-12-02

    IR 

  • Low Reynolds number turbulent flows over elastic walls

    Marco E. Rosti , Luca Brandt

    … We study the laminar and turbulent channel flow over a viscous hyper-elastic wall and show that it is possible to sustain an unsteady chaotic turbulent-like flow at any Reynolds number by properly choosing the wall elastic modulus. … We vary the bulk Reynolds number from 2800 to 10 and identify two distinct mechanisms for turbulence production. …

    Physics of Fluids 32(8), 083109, 2020-08-20

    IR 

  • Heat Transfer of Three-Dimensional Backward-Facing Step Flow : Local Heat Transfer Coefficients on the Bottom Wall and Upper Wall

    Shuai Zou , Takeshi Murayama , Shogo Motoda , Shumpei Hara , Kyoji Inaoka

    ダクト内流路の3次元後方向きステップモデルにおける流れと熱伝達のメカニズムは、特に比較的低いレイノルズ数領域において、未だ十分に解明されていない。本報では、ステップ下壁面と上壁面の局所熱伝達率分布を感温液晶法によって求め、熱伝達率の低下、増大とその発生原因を究明する。用いた感温液晶面の呈色(RGB値)と温度の関係づけにはMLP(多層パーセプトロン)法を用いた。校正後の予備実験は、熱流束一定の条件で …

    同志社大学ハリス理化学研究報告 = The Harris science review of Doshisha University 61(2), 125-131, 2020-07

    IR  DOI 

  • Advection-Diffusion Equation Solver by Analytical Integration Method for the High Reynolds Number Flow  [in Japanese]

    山田 義博 , 登坂 宣好

    計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science 25, 5p, 2020-06

  • Numerical Analysis of Generation of Sound, Aerodynamic Force, and Vortices Associated with Flapping Wing Motion  [in Japanese]

    青野 光 , 吉川 晃平 , 石川 仁 , Aono Hikaru , Kikkawa Kohei , Ishikawa Hitoshi

    第51回流体力学講演会/第37回航空宇宙数値シミュレーション技術シンポジウム (2019年7月1日-3日. 早稲田大学早稲田キャンパス国際会議場), 新宿区, 東京形態: カラー図版あり資料番号: AA1930011018レポート番号: JAXA-SP-19-007

    宇宙航空研究開発機構特別資料: 第51回流体力学講演会/第37回航空宇宙数値シミュレーション技術シンポジウム論文集 = JAXA Special Publication: Proceedings of the 51st Fluid Dynamics Conference / the 37th Aerospace Numerical Simulation Symposium (JAXA-SP-19-007), 201-205, 2020-02-04

    IR 

  • Development of a high-speed and high-precision turbulent flow solver using hierarchical cartesian grids  [in Japanese]

    高木 亮治 , 河合 宗司 , 福島 裕馬 , 玉置 義治 , 堤 誠司 , 柴田 寿一 , Takaki Ryoji , Kawai Soshi , Fukushima Yuma , Tamaki Yoshiharu , Tsutsumi Seiji , Shibata Hisaichi

    第51回流体力学講演会/第37回航空宇宙数値シミュレーション技術シンポジウム (2019年7月1日-3日. 早稲田大学早稲田キャンパス国際会議場), 新宿区, 東京形態: カラー図版あり資料番号: AA1930011014レポート番号: JAXA-SP-19-007

    宇宙航空研究開発機構特別資料: 第51回流体力学講演会/第37回航空宇宙数値シミュレーション技術シンポジウム論文集 = JAXA Special Publication: Proceedings of the 51st Fluid Dynamics Conference / the 37th Aerospace Numerical Simulation Symposium (JAXA-SP-19-007), 165-171, 2020-02-04

    IR 

  • Experimental study on the flow-induced vibration of co-rotating disks in a cylindrical enclosure at transitional Reynolds numbers  [in Japanese]

    HATTORI Yoshiyuki , KAWATA Takuya , OBI Shinnosuke

    … <p>To achieve higher density Hard Disk Drive (HDD), Helium–sealed HDD has been used recently in the aim of decreasing the flow–induced vibration (FIV) of the disks. … Previous researches have been conducted at higher Reynolds numbers, at which the flow between the disks is fully turbulent as in commercial HDDs with air. …

    The Proceedings of the Fluids engineering conference 2020(0), OS13-01, 2020

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  • Flow analysis of low aspect ratio Taylor-Couette flow by means of particle image velocimetry  [in Japanese]

    KAWAGUCHI Tatsuya , SAITO Takushi , SATOH Isao

    … <p>Flow measurements and analysis in the low aspect ratio rotating concentric cylinders(Taylor-Couette flow) were performed in terms of the flow structure. … Particle image velocimetry was used to obtain the axial and radial velocity fluctuations on a meridional plane of Taylor-Couette flow. …

    The Proceedings of the Fluids engineering conference 2020(0), OS04-13, 2020

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  • A Study of the Squeeze Flow between Two Parallel Disks under Sinusoidal Pressure Oscillations  [in Japanese]

    KATO Shunya , NAKANISHI Tameo , KOGANEZAWA Takara , SAITOU Junichi , MISAWA Takao , WATANABE Yoshiyuki , KATOH Mutsuto , SAMORI Petrus Yesaya

    … As the first step of the research, we investigated the liquid squeeze flow between the ultrasonic vibrating surface and the static plate without micropores. … The compressibility of the liquid becomes remarkable at high-frequency ultrasonic vibration. … To accommodate this situation with incompressible flow approximation, it is vital to impose a vibrating pressure boundary condition on the vibrating surface. …

    The Proceedings of the Fluids engineering conference 2020(0), OS04-08, 2020

    J-STAGE 

  • Visualization of Flow and Forces in Swimming  [in Japanese]

    NAKASHIMA Motomu

    <p> 水泳,特に泳速度を競う競泳は,物理的に見て非常に複雑な現象である,泳者身体の多くの部分は水中,一部は空中であり,泳者は多自由度の三次元運動を行い,水中の流れは高レイノルズ数の乱流となる,よって力学的な研究対象としては大変チャレンジングであり,逆に言えば研究しがいのある対象である.筆者は20年近く競泳を対象として研究を行っており,本稿では可視化の観点からその取り組みのいくつかを紹 …

    Journal of the Visualization Society of Japan 40(157), 14-17, 2020

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