Details of a Researcher - Obi, Shinnosuke

Presentations -

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Experimental and computational fluid dynamic analysis of laboratory-scaled counter-rotating cross-flow turbines in marine environment

DOAN MINH N., ALAYETO IVAN H., PADRICELLI CLAUDIO, OBI SHINNOSUKE, TOTSUKA YOSHITAKA

ASME 2018 5th Joint US-European Fluids Engineering Summer Conference (Montreal, Quebec, Canada) ,

2018.07

Oral presentation (general), ASME FED

Experimental study on modeled caudal fins propelling by elastic deformation

BABA NAOMICHI, OBI SHINNOSUKE

ASME 2018 5th Joint US-European Fluids Engineering Summer Conference (Montreal, Quebec, Canada) ,

2018.07

Oral presentation (general), ASME FED

Measurement of the fluctuating pressure on the shroud wall of a hard-disk drive model

SONODA YOSHIHIRO, SANADA KOHEI, OBI SHINNOSUKE

9th International Symposium on Turbulence, Heat and Mass Transfer (Rio de Janeiro) ,

2018.07

Oral presentation (general), International Center for Heat and Mass Transfer

Emergent Issues in Education at Japanese Universities

OBI SHINNOSUKE

NAFSA2018 Annual Conference & Expo (Philadelphia, PA) ,

2018.05

Oral presentation (general), NAFSA

Regional Report: Some national projects for internationalization of universities in Japan

OBI SHINNOSUKE

Asia Pacific Association of International Education Conference 2018 (Singapore) ,

2018.03

Other, Asia Pacific Association of International Education

Measurement of Fluctuating Pressure on the Inner Shroud Wall of a Simplified HDD Model with RW Arm

SANADA KOHEI, OBI SHINNOSUKE

IIP2018 情報・知能・精密機器部門講演会 (埼玉) ,

2018.03

Oral presentation (general), 日本機械学会情報・知能・精密機器部門

In the hard disk drive (HDD), the high-speed rotation of the disk generate turbulent air flow. The turbulent flow causes vibration of the disks and RW arm. The flow induced vibration (FIV) is a major obstacle in improving the performance and reliability of the HDD. Therefore, the investigation on the details of the flow structures and its relationship with FIV are of great engineering imp ortance. In this research, fluctuating pressure measurement on the inner wall of simplified HDD model was performed changing arm insertion angle. Accompanying changes in the arm insertion angle, changes in the flow structure and in the frequency of the pressure fluctuation spectrum were confirmed.

Assessment of New Viscous Diffusion Scheme for Vortex Particle Method

KOBAYASHI YUTAKA, KIRCHART MATTHIAS, OBI SHINNOSUKE

第31回数値流体力学シンポジウム (京都) ,

2017.12

Oral presentation (general), 日本流体力学会

Splitting-free vorticity redistribution method was developed in Kirchhart (4) in order to avoid viscous-splitting when modeling the diffusion term of the vorticity transport equation. The method instead approximates the
Laplacian directly. New scheme such as small neighborhoods significantly reduced the method’s computational cost. In the assessment of this method to a radial symmetric vorticity field, fine agreement with the previous calculation done by Beale and Majda (5) in the case of inviscid was confirmed. The second order convergence to the exact solution was also observed. Then, the convergence of the results to the inviscid case for vanishing viscosity was verified.

Design, experimental analysis, and unsteady Reynolds averaged Navier-Stokes simulation of laboratory-scale counter-rotating vertical-axis turbines in marine environment

MINH N. DOAN, CLAUDIO PADRICELLI, OBI SHINNOSUKE, TOTSUKA YOSHITAKA

DFD17 Meeting of The American Physical Society (Denver, Colorado) ,

2017.10

Oral presentation (general), The American Physical Society

We present the torque and power measurement of laboratory-scale counter-rotating vertical-axis hydrokinetic turbines, built around a magnetic hysteresis brake as the speed controller and a Hall-effect sensor as the rotational speed transducer. A couple of straight-three-bladed turbines were linked through a transmission of spur gears and timing belt and coupled to the electronic instrumentation via flexible shaft couplers. A total of 8 experiments in 2 configurations were conducted in the water channel facility (4-m long, 0.3-m wide, and 0.15-m deep). Power generation of the turbines (0.06-m rotor diameter) were measured and compared with that of single turbines of the same size. The wakes generated by these experiments were also measured by particle image velocimetry (PIV) and numerically simulated by unsteady Reynolds-averaged Navier-Stokes (URANS) simulation using OpenFOAM. Preliminary results from wake measurement indicated the mechanism of enhanced power production behind the counter-rotating configuration of vertical-axis turbines.

Experimental study on self-propelling plates by elastic deformation

BABA NAOMICHI, OBI SHINNOSUKE

日本流体力学会年会2017 (東京) ,

2017.09

Oral presentation (general), 日本流体力学会

An experimental study was conducted for self-propelling fin plates in the fluid at rest. The plates were oscillated at constant amplitude and frequency in the direction normal to its plane, and self-propelled in a devise similar to a merry-go-round. The self-propelling speed and vibration characteristics were measured for modeled caudal fins which had two variable geometric parameters: The length of leading edge Llead, and the chord length Lchord along the centerline. The experiments were undertaken for fins of 9 different shapes at the forcing frequency varying from 1.0 Hz to 10 Hz, resulting in the self-propelling speed of nearly 300 mm/s at most. It was found that Llead solely affects the magnitude of trailing edge amplitude and self-propelling speed, while Lchord influences the Vibration mode of the plates. The effect of elasticity has been found to be of primary importance, and there are possibilities to maximize the self-propelling speed by choosing an appropriate combination of the shape and material of the fin and the forcing frequency.

LES Analysis of Horse-shoe Vortex around the Base of a Circular Cylinder by Means of a Lattice Boltzmann Method

SEIKE YUSUKE, OBI SHINNOSUKE, LINTERMANN ANDREAS

日本流体力学会年会 2017 (東京) ,

2017.09

Oral presentation (general), 日本流体力学会

The horse-shoe vortex appearing in front of the circular cylinder placed on the boundary layer was numerically investigated. The unsteady, three-dimensional feature of the flow field was captured by a lattice-Boltzmann method, where more than 300 million grids were used. The visualized instantaneous flow field indicated a complex vortex structure before and behind the cylinder. The spectrum analysis on the fluctuating pressure in these vortices indicated, however, there are only weak correlations between the horse-shoe vortex in front of the cylinder and the shed vortices in the wake. A strong down-ward flow in front of the cylinder was generated as a consequence of the horse-shoe vortex. The wall shear stress on the bottom wall
was found to be maximum around the corner of the cylinder, as a consequence of the flow acceleration due to the down-ward flow which was related to the generation of the horse-shoe vortex.

PIV Measurement of Horseshoe Vortex around a Circular Cylinder in Turbulent Boundary Layer

SUMIMURA NAOYA, OBI SHINNOSUKE

日本流体力学会年会2017 (東京) ,

2017.09

Oral presentation (general), 日本流体力学会

The behavior of horseshoe vortex around a circular cylinder mounted on the bottom of turbulent boundary layer was experimentally investigated. The velocity field was measured by a PIV for the Reynolds number, based on the oncoming flow velocity and the cylinder diameter, of ReD=11,500 on the mid-plane in front of the cylinder. The time-averaged streamlines and vorticity distribution as well as the Q-criteria confirmed the existence of the fluctuating vortices. The PDF of fluctuating velocity beneath the vortices indicated a good agreement with previous studies. The temporal variation of the horseshoe vortex was also analyzed by observing the x-t diagram of u at different planes parallel to the bottom wall. It was confirmed that the horse-shoe vortex meanders within a certain range in the streamwise direction, while it disappears or merges with tertiary vortices at random in time.

Parametric study on a numerical model for nano-second pulse plasma actuator of flow control over an airfoil

KATO KENTARO, OBI SHINNOSUKE, Breitsamter Christian

Annual meeting of JSFM 2016 (Nagoya) ,

2016.09

Oral presentation (general), Japan Society of Fluid Mechanics

HDD内乱流場におかれたアームに作用する流体力の数値シミュレーション

TAMARU AKIHIRO, OBI SHINNOSUKE

IIP2016　情報・知能・精密機器部門（IIP部門）講演会 (東洋大学　白山キャンパス) ,

2016.03

Oral presentation (general), 一般社団法人日本機械学会

HDDモデル内壁面における変動圧力計測

MASAMOTO KAI,NAKAMURA TUNEYOSHI, OBI SHINNOSUKE

IIP2016　情報・知能・精密機器部門（IIP部門）講演会 (東洋大学　白山キャンパス) ,

2016.03

Oral presentation (general), 一般社団法人日本機械学会

ハードディスク内のアームに作用する流体力の計測

NAKAMURA TUNEYOSHI, OBI SHINNOSUKE

関東学生会第55回学生員卒業研究発表講演会 (東京工業大学　大岡山キャンパス) ,

2016.03

Oral presentation (general), 一般社団法人日本機械学会

脳動脈瘤治癒を目的としたステントの流動抵抗計測

TOYODA AKIHIRO, OBI SHINNOSUKE

関東学生会第55回学生員卒業研究発表講演会 (東京工業大学　大岡山キャンパス) ,

2016.03

Oral presentation (general), 一般社団法人日本機械学会

動脈瘤治療を目的としたパイプラインステントの流動解析

クルカルニ　チャイタンニヤ、セガス　ラファエル、デュオング　ダヴィッド、小尾晋之介、立嶋　智

第28回バイオエンジニアリング講演会 (東京工業大学　大岡山キャンパス) ,

2016.01

Oral presentation (general), 一般社団法人日本機械学会

インビトロとCFDを用いた血管屈曲がパイプラインの整流効果に及ぼす影響

OBI SHINNOSUKE

The 31th Annual Meeting of the Japanese Society for Neuroendovascular Therapy (Okayama Convention Center) ,

2015.11

Oral presentation (general), The Japanese Society for Nueroendovascular Therapy

パイプライン留置から動脈瘤の治癒に至る機序は完全に理解されていない。前床突起部など屈曲が強い血管での治療成績が一定せず、コイル塞栓を併用するなどの姑息的解決策が取られている。今回我々は血管屈曲が整流効果に与える影響を検証した。
血管屈曲が整流効果に与える影響は大きく、メッシュ密度と同様に重要なパラメーターとして考慮する必要がある。

ナノ秒パルスプラズマアクチュエータを用いた翼上の流れ制御のための数値モデル

Kentaro Kato, OBI SHINNOSUKE, Breitsamtr Christian

第93期流体工学部門講演会 (東京理科大学　葛飾キャンパス) ,

2015.11

Oral presentation (general), 東京理科大学一般社団法人日本機械学会

移動平板の誘起する渦流れ構造と力の渦法による数値解析

Yusuke Kunii, Alex Jhon Sepnov, Fuminori Hioki, OBI SHINNOSUKE

第93期流体工学部門講演会 (東京理科大学　葛飾キャンパス) ,

2015.11

Oral presentation (general), 東京理科大学一般社団法人日本機械学会

半円オリフィス管内乱流のステレオPIV計測及び壁面静圧計測

Yoshinori Yasuoka, OBI SHINNOSUKE

第93期流体工学部門講演会 (東京理科大学　葛飾キャンパス) ,

2015.11

Oral presentation (general), 東京理科大学一般社団法人日本機械学会

LES study of the turbulent flow in a HDD model

TAMARU AKIHIRO,OBI SHINNOSUKE

8th International Symposium on Turbulence, Heat and Mass Transfer (Sarajevo, Bosnia and Herzegovina) ,

2015.09

Oral presentation (general), Faculty of Mechanical Engineering of the University of Sarajevo, BH International University of Sarajevo, BH

Three-dimensional turbulent recirculating flow in a pipe with semi-circular orifice

YASUOKA YOSHINORI,OBI SHINNOSUKE

8th International Symposium on Turbulence, Heat and Mass Transfer (Sarajevo, Bosnia and Herzegovina) ,

2015.09

Oral presentation (general), Faculty of Mechanical Engineering of the University of Sarajevo, BH International University of Sarajevo, BH

Application of a discrete vortex method to analyze the vortex flow induced by an oscillating flat plate

KUNII YUSUKE, OBI SHINNOSUKE

13th US National Congress on Computational Mechanics (San Diego, CA., USA) ,

2015.07

Oral presentation (general), USACM

Flow control over swept wings using nanosecond-plasma actuator

KATO KENTARO, OBI SHINNOSUKE

9th International Symposium on Turbulence and Shear Flow Phenomena(TSFP-9) (The University of Melbourne) ,

2015.06

Oral presentation (general), The University of Melbourne

Large eddy simulation for turbulent flow in a simplified HDD model using OpenFOAM

TAMARU AKIHIRO, OBI SHINNOSUKE

2015 JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment (Kobe International Conference Center) ,

2015.06

Poster presentation, JSME, ASME

Experimental Study on the Turbulent Flow in a Simplified HDD model

MASAMOTO KAI, OBI SHINNOSUKE

2015 JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment (Kobe International Conference Center) ,

2015.06

Poster presentation, JSME, ASME

圧力計速報を用いた馬蹄形渦の計測

OBI SHINNOSUKE, MAEDA HOSHITO

土木学会第18回応用力学シンポジウム (金沢大学) ,

2015.05

Poster presentation, 土木学会応用力学委員会

Numerical Analysis of Vortex Flow Structure and Force Induced by Oscillating Flat Plate using Vortex Method

KUNII YUSUKE, ALEX JOHN SEPNOV, HIOKI NORIFUMI, OBI SHINNOSUKE

JSME Kanto Chapter 21st Conference (Yokohama) ,

2015.03

Oral presentation (general), Japan Society of Mechanical Engineers

Large eddy simulation for turbulent flow in a HDD model by OpenFOAM

TAMARU AKIHIRO, OBI SHINNOSUKE

JSME Kanto Chapter 21st Conference (Yokohama) ,

2015.03

Oral presentation (general), Japan Society of Mechanical Engineers

Stereo PIV measurement of turbulent pipe flow with semicircle orifice

OBI SHINNOSUKE, YASUOKA YOSHINORI

JSME Kanto Chapter 21st Conference (Yokohama) ,

2015.03

Oral presentation (general), Japan Society of Mechanical Engineers

Fluctuating hydraulic-pressure measurement in a turbulent wingtip vortex

MAEDA HOSHITO, KAWATA TAKUYA, OBI SHINNOSUKE

10th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements (Marbella, Spain) ,

2014.09

Oral presentation (general), ERCOFTAC

Experimental study of turbulent flow between shrouded co-rotating disks

TAKAHASHI MASAYUKI, OBI SHINNOSUKE, KAWATA TAKUYA

10th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements (Marbela, Spain) ,

2014.09

Oral presentation (general), ERCOFTAC

ナノ秒パルスプラズマアクチュエータによる２次元翼，後退翼上における流体制御

KATO KENTARO, CHRISTIAN BREITSAMTER, OBI SHINNOSUKE

2014 年度日本機械学会年次大会講演会 (東京) ,

2014.09

Oral presentation (general), 日本機械学会

ナノ秒パルス波を用いたDBD-PA の2 次元的な流れ，及び3 次元的な流れへ
の制御評価を行った。2 次元的な流れである矩形翼G¨o 387 上に発達する流れでは，迎角の上昇とともに，翼上の剥離がスパン方向にほぼ均一に起こり，急激に揚力が減少した。3 次元的な流れである後退翼NACA65A005上に発達する流れでは，前縁渦は迎え角の増加とともに後方から徐々に崩壊し，緩やかな失速に至った。

HDDモデル内アーム近傍流れのLES解析

SHIMSMURA MASASHI, OBI SHINNOSUKE

第28回生研TSFDシンポジウム (東京) ,

2013.03

Oral presentation (general), 東京大学生産技術研究所TSFD研究グループ

ハードディスクドライブ内に発達する乱流をLESで数値解析し、データ読み書きヘッドを固定するアームに作用する流体力を求めた。アームの背後を通過する流量を変化させることでアームに作用する流体力を変化させ、その影響を、アームに作用する圧力変動トルク、粘性応力変動トルクで評価した。先年に行った類似の計算結果と比較しててわずかなアームの形状変更により流れ場に大きな変化が生じることが明らかになった。

移動壁面を有する密閉容器内流れの渦法解析

OBI SHINNOSUKE

日本機械学会第90期　流体工学部門講演会 (京都) ,

2012.11

Oral presentation (general), 日本機械学会流体工学部門

Experimental and numerical investigation on a fully developed turbulent pipe flow over a semicircle orifice

OKUDA SEIYA, LEPEUT CHARLES-HENRI, RASTI MELIKA, KAWATA TAKUYA, OBI SHINNOSUKE

7th International Symposium on Turbulence, Heat and Mass Transfer (Palermo, Italy) ,

2012.09

Oral presentation (general)

The internal separated flow associated with remarkable mean secondary flow is investigated. The
numerical investigation indicates that the commercially available RANS model group and LES provide obvious
difference in terms of the prediction of the flow reattachment and recovery. The stereo PIV measurement indicates
over-proportional magnitude of the velocity fluctuation across the mean flow direction, and it is obviously
challenging for LES to capture the extremely complex flow pattern. The recirculation region in either side of the
orifice seems to be the source of the streamwise vortex that governs the development of the flow near the flow
reattachment point. The considered flow serves as a useful test case for both RANS modeling and LES.

Simultaneous measurement of fluctuating velocity and pressure using stereo-PIV and static-pressure probe in a turbulent wing-tip vortex

KAWATA TAKUYA, OBI SHINNOSUKE

7th International Symposium on Turbulence, Heat and Mass Transfer (Palermo, Italy) ,

2012.09

Oral presentation (general)

Simultaneous measurement of the fluctuating pressure and velocity field is performed using a
miniature static-pressure probe and a stereo-PIV. The static-pressure probe is placed just behind the velocity
measuring plane illuminated by the laser sheet, and the instantaneous velocity field and the fluctuating
pressure are measured simultaneously in a turbulent wing-tip vortex flow. The instantaneous pressure field
is estimated by numerically solving a discrete two-dimensional Poisson equation for pressure. The result is
compared to directly measured pressure for validation.

ＰＩＶと小型静圧プローブを用いた変動速度・圧力同時計測

OBI SHINNOSUKE

日本流体力学会年会2012 (高知) ,

2012.09

Oral presentation (general), 日本流体力学会

半円オリフィスを過ぎる完全発達管内乱流の実験研究

OBI SHINNOSUKE

日本流体力学会年会2012 (高知) ,

2012.09

Oral presentation (general), 日本流体力学会

回転積層円盤間流れの変動圧力計測

OBI SHINNOSUKE

日本流体力学会年会2012 (高知) ,

2012.09

Oral presentation (general), 日本流体力学会

Investigation of turbulent Couette-like behaviors in a rotating flow

SHIRAI KATSUAKI, SHIGA NOBUO, BUETTNER LARS, OBI SHINNOSUKE, CZARSKE JUERGEN

16th International Symposium on Applications of Laser Techniques to Fluid Mechanics (Lisbon, Portugal) ,

2012.07

Oral presentation (general)

Complex flow inside a hard-disk drive (HDD) was investigated using a simplified 3.5” model to clarify the mechanism causing flow-induced vibration. In contrast to most HDD studies in the past, our model had a non-axisymmetric geometry equipped with a shroud opening and a read/write arm (RWA). The model is designed to serve as a benchmark to study HDD flows both in experiments and in numerical simulations. The secondary flow behavior was likely caused by the shroud opening which wasn’t used in most of the models in the past. In experiment II, the
mean velocity and velocity variance were successfully measured through examination of the flow above and
below the RWA in the space between the rotating disks. The resulting velocity statistics show turbulent
Couette-like flow in the narrow 1 mm space between the disks and the RWA. In addition to the flow
measurements, deflections of components in the model were evaluated during operation, which will provide
precise boundary conditions for future numerical simulations.

Experimental investigation of the flow behavior near the read-and-write arm in a hard disk drive model with shroud opening

SHIRAI KATSUAKI, SHIGA NOBUO, BUETTNER LARS, CZARSKE JUERGEN, OBI SHINNOSUKE

2012 ASME-ISPS /JSME-IIP Joint International Conference on Micromechatronics for Information and Precision Equipment (Santa Clara, CA) ,

2012.06

Oral presentation (general), American Society of Mechanical Engineers

We report a detailed measurement of flow velocities in a simplified, transparent 3.5” hard-disk drive (HDD) model.The simplified geometry of the new model allows systematic flow investigation both in experiments and in numerical simulations. A focus is put on the flow behaviors in the disk-to-disk space with the RWA being inserted. The velocity statistics obtained in the narrow space of 500 μm by means of a novel laser Doppler velocity profile sensor are presented and discussed in this extended abstract.

LES Study of flow between shrouded co-rotating disks

WASHIZU TOMOYA, OBI SHINNOSUKE

9th International ERCOFTAC Symposium on Engineering Turbulence Modeling and Measurements (Thessaloniki, Greece) ,

2012.06

Oral presentation (general), European Research Community of Flow, Turbulence and Combustion

Large eddy simulations of the turbulent flow between shrouded co-rotating disks, representing a simplified model of hard disk drives, are performed.
The computation domain extended a region covering the both sides of a disk, so that the fluctuating pressure field surrounding the disk is simulated.
Besides, the influence of the shroud geometry is investigated by comparing the flat shroud wall and the one with the ribs.
In the case of flat shroud, the fluctuating pressure on the upper- and lower-surface of a disk indicated a strong correlation with the fluid motion travelling across the disk-tip clearance.
In the ribbed shroud case, however, the organized flow structure that is observed in the flat shroud case disappeared, and the fluctuating pressure acting on the surface of the disk is remarkably diminished.

PIV Measurement and force estimation of the flow induced by a heaving elastic plate

KATO KENTARO, OBI SHINNOSUKE

9th International ERCOFTAC Symposium on Engineering Turbulence Modeling and Measurements (Thessaloniki, Greece) ,

2012.06

Oral presentation (general), European Research Community of Flow, Turbulence and Combustion

The vortical uid motion caused by a heaving elastic
plate was experimentally investigated. The thin
plate was oscillated in the direction normal to its plane
in the water at rest. The vortices generated at the tip
of the plate were observed at the mid-span plane and
the velocity eld was measured by means of a particle
image velocimetry (PIV). The measurements were undertaken
at different frequencies of the oscillation relative
to the resonance frequency of the plate. As a result,
phase-averaged momentum ux through these control
surfaces illuminated the effect of relative frequency.

円筒容器内積層回転円盤間乱流のLES

WASHIZU TOMOYA, OBI SHINNOSUKE

第27回生研TSFDシンポジウム (東京) ,

2012.03

Oral presentation (general)

加速する平行平板間流れへの三次元渦法の適用

HIOKI FUMINORI, YOKOTA RIO, OBI SHINNOSUKE

日本流体力学会年会2011 (東京) ,

2011.09

Oral presentation (general), 日本流体力学会

渦度場の時間発展に着目する渦法では、渦度分布を有する渦要素の重ね合わせで渦度場を表現し、渦要素の運動をラグランジュ的に解析する。外部流れのように渦度が領域内の限られた範囲にだけ存在する場合に有利であるが、反面、領域全体が渦度で満たされる内部流れではその検証が十分になされていない。本研究では基礎的な問題として時間とともに発達するチャネル流れを取り上げ、渦度輸送方程式では取り扱うことのできない圧力勾配項を合理的に表現する手法について考察する。

容器内積層回転円盤間乱流のLES

WASHIZU TOMOYA, OBI SHINNOSUKE

日本流体力学会年会2011 (東京) ,

2011.09

Oral presentation (general), 日本流体力学会

過去の実験から得られた知見に基づき，シュ
ラウド壁面が平滑なものと，リブ付きシュラウドの2 つのモデ
ルについて積層回転円盤間に発達する乱流のLES を行い，流体
運動と圧力変動について知見を得ることを目的とする．その際，
1 枚のディスク上下の両面に発達する流れ場の相互干渉を再現
するため，計算領域を3 枚のディスクに囲まれた2 つの隣接す
る領域とした

ヒービング運動する弾性板が誘起する流れ場のPIV 計測

KATO KENTARO, OBI SHINNOSUKE

日本流体力学会年会2011 (東京) ,

2011.09

Oral presentation (general), 日本流体力学会

半円オリフィス乱流のPIV 計測と数値解析

OKUDA SEIYA, LEPEUT CHARLES-HENRI, OBI SHINNOSUKE

日本流体力学会年会2011 (東京) ,

2011.09

Oral presentation (general), 日本流体力学会

Investigation of complex flow behaviors in a hard disk drive model with read-and-write arm and shroud opening

SHIRAI KATSUAKI, SHIGA NOBUO, BÜTTNER LARS, CZARSKE JÜRGEN OBI SHINNOSUKE

Fachtagung “Lasermethoden in der Strömungsmesstechnik” (Ilmenau) ,

2011.09

Oral presentation (general)

Flow inside a hard-disk drive (HDD) is investigated using a simplified 3.5” HDD model with read-and-write arm (RWA) and shroud opening. The model was designed to serve as a benchmark of HDD flow investigation both in experiments and in numerical simulations. In the present study, complex flow behaviors in the narrow disk-to-disk space are focused with the RWA inserted into the space. Especially, the flow behavior near the RWA is of great interest. The velocity statistics are acquired at four different locations using a velocity profile sensor with a spatial resolution of 5 μm along the axial direction. The measurement was carried out at the disk Reynolds number ReD=2.4×105, which corresponds to the rotation speed of 7700 rpm at a real 3.5” HDD for desktop computers. The velocity profile sensor successfully resolved the velocities between the narrow areas without disturbing the flow.

On reformulating the ERM-based second-moment closure towards a more robust turbulence model

HUI JING, OBI SHINNOSUKE, JAKIRLIC SUAD

7th International Symposium on Turbulence and Shear Flow Phenomena (Ottawa) ,

2011.07

Oral presentation (general)

The present study considers a reformulation of the
Durbin’s (1993) ERM-based second-moment closure model
aiming at reduction of the numerical stiffness originating
from the wall boundary conditions. The reformulation
performed represents an analogy to the procedure Hanjalic et
al. (2004) proposed when deriving the eddy-viscosity-based
zeta-f model. The presently reformulated model alternatively
solves the transport equations for the ratio of the Reynolds
stress components to turbulent kinetic energy zeta_ij = u_i u_j/k,
instead of equations governing the Reynolds stress tensor. It is believed that the boundary conditions of the newly derived elliptic relaxation equations will contribute to the numerical robustness of the model with respect to the immediate wall vicinity. Another advantage, analogously to the Hanjalic’s et al. zeta-f model, is the appearance of the Reynolds stress production rate (representing an exact formulation) in the zeta_ij equations instead of dissipation rate epsilon (originating from
the corresponding model equation). Application of the
present model formulation to a plane channel flow in a range
of Reynolds numbers up to Re_t = 2003 results in a good
agreement with available DNS database.

Velocity-pressure correlation measurement using various static-pressure probe in a wake of circular cylinder

KAWATA TAKUYA, NAKA YOSHITSUGU, FUKAGATA KOJI, OBI SHINNOSUKE

7th International Symposium on Turbulence and Shear Flow Phenomena (Ottawa) ,

2011.07

Oral presentation (general)

An experimental investigation is conducted into the effect of the shape of a miniature static-pressure probe on the velocity-pressure correlation measurement.
Ten static-pressure probes, with systematically-changed probe diameters and lengths, are compared in combination with an X-type hot-wire probe to examine the accuracy of the simultaneous measurement of the fluctuating velocity and pressure.
The effect of the probe shape on the distance between the probes, which is necessary to avoid interference, is also investigated for the various pressure probes, and it is found that the change in probe diameter has the primary influence on the probe interference.
In the velocity-pressure correlation measurements, the results of the pressure fluctuation p' and the velocity-pressure correlation up are not affected by the probe shape.
On the other hand, it is indicated that the measurement of vp is extremely sensitive to the configuration of the pressure holes including its orientation.

Velocity measurements of gap flows at a computer hard disk model

SHIRAI KATSUAKI; BUETTNER LARS; CZARSKE JUERGEN, OBI SHINNOSUKE

SENSOR+TEST 2011 (Nuremberg, Germany) ,

2011.06

Oral presentation (general), Organizing Committee

The gap flow in the tip clearance of a hard disk drive model has been investigated with optical measurment techniques. The flow was driven by co-rotating disks inside a cylindrical enclosure in order to simulate a hard disk drive for data storage devices. The main focus of the investigation was the understanding of the complex flow behaviors in the narrow region between the disk tip and the
outer shroud wall, which is supposed to be one of the causes of flow induced vibrations of the disks.

速度・圧力相関計測に対して静圧プローブの形状が与える影響

KAWATA TAKUYA, NAKA YOSHITSUGU, FUKAGATA KOJI, OBI SHINNOSUKE

第60回理論応用力学講演会 (東京) ,

2011.03

Oral presentation (general), 第60回理論応用力学講演会実行委員会

ヒービング運動する弾性板周りのPIV計測

KATO KENTARO, OBI SHINNOSUKE

第60回理論応用力学講演会 (東京) ,

2011.03

Oral presentation (general), 第60回理論応用力学講演会実行委員会

Pressure estimation on the surface of a sinusoidally oscillating plate in quiescent fluid

SURYADI ALEXANDRE, OBI SHINNOSUKE

The 5th International Conference of Vortex Flows and Vortex Models (Caserta, Italy) ,

2010.11

Oral presentation (general)

This paper presents a method to calculate the pressure field from the far-field to the near-surface of a periodically moving plate. The flow around a simple sinusoidally flapping plate was measured to investigate the dynamics of flow separation and its connection to the production of force of a flapping wing. The flow was measured using stereo PIV at different (out-of-plane) positions relative to the plate to resolve the deformation tensor. Torque acting on the rotation axis was estimated from the velocity field data by solving the pressure equation expressed in the form of Poisson equation. The results were compared with torque measured with strain gauges that were applied on the axis of rotation. The result shows dissimilarity of the pressure field between Re = 1580 and Re = 3160. Torque estimated from the pressure field shows similarity with the torque measured with strain gauges. Although the method shows promising result, it requires further rigorous testing.

Investigation of three-dimensional tip clearance flow inside a hard disk drive model

SHIRAI KATSUAKI, YAGUCHI YUSUKE, BUETTNER LARS, CZARSKE JUERGEN, OBI SHINNOSUKE

15th Symposium on Application of Laser Techniques to Fluid Mechanics (Lisbon, Portugal) ,

2010.07

Oral presentation (general)

Flow in the tip clearance of a hard disk drive model has been investigated with laser Doppler techniques. The velocity measurements were carried out with two different types of laser Doppler sensors. One was a conventional
laser Doppler velocimetry and the other a novel laser Doppler velocity profile sensor with a spatial
resolution in the micrometer range. The circumferential velocity component was measured along the axial and radial directions. The velocity statistics obtained with both sensors have good agreements in general, but those measured with the conventional velocimetry suffered from a spatial averaging effect.

Surface pressure calculation of flapping wing from three-dimensional velocity field acquired by PIV

SURYADI ALEXANDRE, OBI SHINNOSUKE

14th International Symposium on Flow Visualization (Daegu, Korea) ,

2010.06

Oral presentation (general)

Aerodynamics of a hard disk drive: Measurements of flow velocity, pressure fluctuation and disk vibration

KURASHIMA DAISUKE, NAKA YOSHITSUGU, FUKAGATA KOJI, OBI SHINNOSUKE

8th ERCOFTAC International Symposium on Engineering Turbulence Modelling and Measurements (Marseille) ,

2010.06

Oral presentation (general), ERCOFTAC

The complex feature inside a prototype hard disk drive is investigated both experimentally and computationally. The experiment focuses on both flow dynamics and the disk vibration, where measurements of fluctuating pressure and velocity are undertaken at some representative points. Certain correlation between the disk vibration and the fluctuating pressure in the turbulent flow between disks is found in the spectra of each signal. The computational approach by LES provides information on the whole flow field as complementary to the point measurements. The experimentally observed fluctuation of pressure and velocity are partly due to the disk vibration and its contribution could be estimated by comparing the experiment with the LES results.

水面波を利用した渦輪の発生

深谷友詞, 長田泰一, 小尾晋之介, 益田重明

第81期日本機械学会流体工学部門講演会 (吹田市) ,

2003.09

Oral presentation (general)

一様流中におかれた２つの鈍い物体周辺の乱流場

酒井圭太, 外海憲彦, 小尾晋之介

第81期日本機械学会流体工学部門講演会 (吹田市) ,

2003.09

Oral presentation (general)

チャネル乱流における乱流エネルギー散逸率輸送方程式へのレイノルズ数効果

津留啓介, 関洋治, 阿部浩幸, 小尾晋之介

日本流体力学会年会2003 (東京) ,

2003.07

Oral presentation (general)

回転円盤上の衝突噴流内乱流統計量

皆川佑介, 小尾晋之介, 益田重明

日本流体力学会年会2002 (仙台) ,

2003.07

Oral presentation (general)

軸対称乱流境界層の剥離挙動

岡田光平, 高木玲, 益田重明

日本流体力学会年会2002 (仙台) ,

2003.07

Oral presentation (general)

マイクロバーストの実験室モデル－重力により駆動される渦輪の性質－

長田泰一, 小尾晋之介, 益田重明

日本流体力学会年会2002 (仙台) ,

2003.07

Oral presentation (general)

MDGRAPE-2を用いた渦法の高速化

朝倉崇顕, 小尾晋之介, 泰岡顕治

第16回数値流体力学シンポジウム (東京) ,

2002.12

Oral presentation (general)

振動を伴うバックステップ乱流のRANSモデル計算

小尾晋之介

日本機械学会,流体工学部門講演会,

2001.10

鈍い物体伴流のRANSモデリング

小尾晋之介

日本流体力学会年会,

2001.08

円錐ディフューザにおける乱流剥離に　伴う壁面静圧変動特性

高木　玲, 市川　正明, 益田　重明,小尾晋之介

日本流体力学会年会,

2001.08

周期的外乱によるバックステップ後流構造の変化について

吉岡　修哉, 小尾晋之介, 益田　重明

日本流体力学会年会,

2001.08

回転積層円盤間の不安定流動と円盤　振動

日下　博之, 小尾晋之介, 益田　重明

日本流体力学会年会,

2001.08

角柱後流の乱流輸送における圧力拡散モデル

小尾晋之介, 中谷　仁之

第38回日本伝熱シンポジウム,

2001.05

鈍い物体伴流の乱流輸送モデル

小尾晋之介、中谷仁之

第16回生研NSTシンポジウム,

2001.03

3次元渦法による乱流解析（粘性散逸に関する検討）

戸塚義孝、小尾晋之介、

第14回数値流体力学シンポジウム,

2000.12

周期的外乱を受けるバックステップ流れの大規模構造

吉岡修哉、小尾晋之介、益田重明

日本機械学会第78期流体工学部門講演会,

2000.09

バックステップ乱流の瞬時圧力分布

小嶋洋太、吉岡修哉、小尾晋之介、益田重明

第32回乱流シンポジウム,

2000.07

3次元渦法解析における高速化手法に関する検討

戸塚義孝、小尾晋之介

第11回計算流体シンポジウム,

2000.07

DNSによる壁面せん断応力計測用ホットフィルムセンサーの評価

河野剛、小尾晋之介、益田重明

第37回日本伝熱シンポジウム,

2000.05

PIV速度データに基づく瞬時圧力場の計測

本坊光朗、小尾晋之介、益田重明

日本機械学会関東支部第6期総会講演会,

2000.03

三次元渦法による渦輪の干渉の並列計算

（戸塚義孝、小尾晋之介）

第13回数値流体力学シンポジウム,

1999.12

代数応力モデルによる二次元非対称ディフューザ内乱流の数値予測

（冲永佳史、小尾晋之介）

第13回数値流体力学シンポジウム,

1999.12

３次元壁面噴流の非等方乱流拡散

（小尾晋之介）

第12回計算力学講演会,

1999.11

代数応力モデルによる二次元非対称ディフューザ内乱流はく離の数値予測

（冲永佳史、小尾晋之介）

第10回計算流体シンポジウム,

1999.07

周期的外乱を受けるはく離せん断層における渦構造について

（吉岡修哉、小尾晋之介、益田重明）

第31回乱流シンポジウム,

1999.07

角柱から放出される渦中の圧力速度相関

（本坊光朗、小尾晋之介、益田重明）

第31回乱流シンポジウム,

1999.07

境界層熱伝達に及ぼすコリオリ力の影響

（江戸　義博、小尾晋之介、益田重明）

第36回日本伝熱シンポジウム,

1999.05

三次元乱流壁面噴流のレイノルズ応力方程式モデルによる数値解析

小尾晋之介

日本機械学会計算工学部門講演会,

1998.11

Oral presentation (general)

バックステップ流れの渦構造に対する周期的外乱の影響について

（吉岡修哉、小尾晋之介、益田重明）

日本機械学会第77期流体工学部門講演会,

1998.10

容器内積層回転円盤間における非定常流

深谷良介市坪健一益田重明小尾晋之介

日本機械学会第76期全国大会,

1998.10

Oral presentation (general)

平板に衝突する渦輪のPIV計測

金谷俊助長田泰一益田重明小尾晋之介

第30回流体力学講演会,

1998.09

Oral presentation (general)

レイノルズ応力方程式を用いたバックステップ流の３次元構造の数値解析

斎藤武小尾晋之介

日本機械学会流体工学部門講演会,

1998.08

Oral presentation (general)

二次元および三次元壁面噴流のレイノルズ応力方程式モデルによる数値解析

小尾晋之介

日本機械学会流体工学部門講演会,

1998.08

Oral presentation (general)

単一傾斜型熱線風速計による二次元混合層の乱流計測

小形俊夫前鶴昭徳小尾晋之介益田重明

第30回乱流シンポジウム,

1998.07

Oral presentation (general)

二次元非対称ディフューザ内乱流のはく離予測について

冲永佳史小尾晋之介

第30回乱流シンポジウム,

1998.07

Oral presentation (general)

回転境界層内のゲルトラー渦と熱伝達特性

小宮山宏江戸義博小尾晋之介益田重明

第30回乱流シンポジウム,

1998.07

Oral presentation (general)

周期的外乱を受けるバックステップ流の運動量輸送について

吉岡修哉小尾晋之介益田重明

第30回乱流シンポジウム,

1998.07

Oral presentation (general)

周期的外乱に対するバックステップ流の応答特性

桝川高久吉岡修哉斎藤武小尾晋之介，益田重明

第29回乱流シンポジウム,

1997.07

二次元混合層における乱流エネルギー収支の測定

小形俊夫伊藤健二小尾晋之介益田重明

第29回乱流シンポジウム,

1997.07

ファイバＬＧＭを用いた壁面せん断応力統計量の計測

古川貴之小尾晋之介益田重明

第34回日本伝熱シンポジウム,

1997.05

主流中の点源撹乱による平板境界層の遷移

濱田慎悟柴田潔小尾晋之介益田重明

日本流体力学会年会96,

1996.07

はく離せん断乱流の周期的外乱に対する応答性

姫木仲秋小尾晋之介益田重明

日本流体力学会年会96,

1996.07

二次元混合層における乱流エネルギー収支の傾斜型熱線による測定

伊藤健二小尾晋之介益田重明

日本流体力学会年会96,

1996.07

回転する積層ディスク間流れの乱流構造

小野孝朗雨宮健一郎小尾晋之介益田重明

日本流体力学会年会96,

1996.07

チャネル乱流の局所壁面せん断応力の統計量

古川貴之今川宏明小尾晋之介益田重明

第33回日本伝熱シンポジウム,

1996.05

乱流せん断層の周期的外乱に対する応答性

姫木仲秋小尾晋之介益田重明

第11回生研ＮＳＴシンポジウム,

1996.03

レイノルズ応力の乱流輸送モデル

原英統小尾晋之介

第27回乱流シンポジウム,

1995.07

二次元混合層における乱流エネルギー消散率の測定

長谷川善幸小尾晋之介益田重明

第27回乱流シンポジウム,

1995.07

周期外乱を受ける乱流はく離流の三次元性

石橋信正小尾晋之介益田重明

第27回乱流シンポジウム,

1995.07

周期的外乱による乱流変動の生成機構に関する数値解析

山本哲也小尾晋之介益田重明

第32回日本伝熱シンポジウム,

1995.05

壁面剪断応力測定のための接着型ホットフィルムの動特性

今川宏明小尾晋之介益田重明

第32回日本伝熱シンポジウム,

1995.05

レーザグラディエントメータによる乱流壁面剪断応力の測定

井上敬太小尾晋之介益田重明

第32回日本伝熱シンポジウム,

1995.05

Prediction of the heat transfer characteristics in a serrated turbulent channel by using a theta-e model

Bethancourt, A. M. Kobayashi, K. P. Yoshida, H. Echigo, R. and Obi, S.

第32回日本伝熱シンポジウム,

1995.05

遠心羽根なしディフューザに発生する旋回失速の自己回帰モデルを用いた能動制御

廣瀬則仁小尾晋之介有賀一郎

日本機械学会第72期通常総会,

1995.03

周期的外乱による乱流はく離制御の数値シミュレーション（レイノルズ応力の生成とはく離制御効果）

山本哲也小尾晋之介益田重明

日本機械学会第72期通常総会,

1995.03

遠心羽根なしディフューザ内の旋回失速に対する能動制御（初期変動の抑制効果）

金井剛有賀一郎小尾晋之介

日本機械学会第72期全国大会,

1994.08

ディフューザ内はく離流における周期変動の発達

石橋信正青木謙太小尾晋之介益田重明

第26回乱流シンポジウム,

1994.07

コリオリ力場の境界層における縦渦に伴う二次不安定性

堀大輔益田重明小尾晋之介

第26回乱流シンポジウム,

1994.07

はく離の周期的な外乱による乱流変動の生成機構

青木謙太小尾晋之介益田重明

第31回日本伝熱シンポジウム,

1994.05

乱流拡散項のモデリングについて

小尾晋之介

第９回生研ＮＳＴシンポジウム,

1994.03

鋸歯状ステップを有する二次元流路内乱流熱伝達の数値解析

小尾晋之介小林健一吉田英夫越後亮三

日本機械学会熱工学講演会,

1993.11

周期的な吹出し吸込みによる乱流制御の数値シミュレーション

山本哲也小尾晋之介益田重明

日本機械学会流体工学部門講演会,

1993.08

周期的外乱による乱流境界層剥離の制御

青木謙太小尾晋之介益田重明

第25回乱流シンポジウム,

1993.07

強い逆圧力勾配を伴う乱流の数値解析のための壁関数の検討

小尾晋之介田中謙介益田重明

第30回日本伝熱シンポジウム,

1993.05

周期的外乱が非定常はく離に及ぼす影響

青木謙太小尾晋之介益田重明

日本機械学会第70期通常総会,

1993.03

低レイノルズ数型乱流モデルを用いた遷移レイノルズ数領域におけるチャンネル流の計算

小尾晋之介益田重明

日本機械学会第70期全国大会,

1992.10

はく離を伴う二次元ディフューザ内乱流の数値解析

小尾晋之介丹羽宏明益田重明

第29回日本伝熱シンポジウム,

1992.05

希薄域における熱線プローブの特性に関する研究

堤一之小尾晋之介益田重明

日本機械学会関西支部第67期定時総会講演会,

1992.03

はく離を伴う逆圧力勾配流れの低Re数型k-εモデルによる数値解析

丹羽宏明小尾晋之介益田重明

日本機械学会関西支部第67期定時総会講演会,

1992.03

周期的な吹出し・吸込みによるディフューザ内乱流剥離の制御

大泉博文小尾晋之介益田重明

日本機械学会関西支部第67期定時総会講演会,

1992.03

レイノルズ応力方程式モデルによる任意形状の流路内乱流の数値解析

小尾晋之介 Peric, M.

第5回数値流体力学シンポジウム,

1991.12

レイノルズ応力方程式モデルによる管内平行流合流過程の数値解析

小尾晋之介益田重明徳山幹夫

日本機械学会流体工学部門講演会,

1991.08

大きな再循環流を伴う円筒容器内の乱流特性

小尾晋之介菱田公一前田昌信横堀誠一

第21回日本伝熱シンポジウム,

1984.06

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