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流体工学部門講演会講演論文集の検索結果

もしかして: 流体工学部門講演会講演論文集 英語 

消化器系管腔粘膜の表面微細構造が摩擦特性へ及ぼす影響 CiNiiでみる

著者名:
下笠 賢二  小原 弘道  水沼 博 

抄録:

Swallowing disorder has been becoming a serious issue with increasing in elderly people. Disorder sometimes appears with a decrease in saliva, because saliva has an important role in lubrication over the oral cavity and throat. Though the structure of biological mucosa has been studied physiologically, there are only few studies that examined the influence of its micro structure on fluid lubrication. Therefore, we investigated the friction characteristics by reproducing the micro structure of oral cavity and pharynx. As an example of the oral cavity mucous membrane, the tongue of a pig was subjected to observation by microscope and laser surface shape and roughness measuring machine. As a result, roughness properties of a pig tongue differed from root part to tip part, and it was confirmed that hemispherical protrusions were observed on the tip part by irregular arrangement. An imitation tongue was produced using a high-precision 3D printer. Furthermore, the concentration of thickener was determined from the measurement of the viscous characteristic by the rotational viscometer to have the same viscosity as that of saliva. It is necessary to evaluate the rheological properties of mucus with low viscosity and high spinnability like saliva, and the viscosity characteristics different from the shear viscosity. Therefore, we investigated the rheological characteristics by measuring the extensional viscosity to make a mucus that simulates saliva.We measured friction force on the imitation tongue lubricated by artificial saliva. The friction force were changed depending on the lubrication condition and the moving speed.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-8 , 
ISSN:

下腎杯内流れと腎結石の挙動の数値シミュレーション CiNiiでみる

著者名:
内田 日出  戸本 幸志郎  永田 貴之  高橋 俊  福田 紘大  木村 啓志  古目谷 暢  松崎 純一 

抄録:

Urinary stones are calcium oxalate stones in the urinary tract. According to the 2005 national survey, the lifetime prevalence of urinary stones is 15.1% for Japanese men and 6.8% for women. In addition, 96% of the whole are upper urinary tract stones such as kidney stones. Small stones are excreted in the urine without feeling great pain in the process of excreting, but when they become large, natural excretory becomes difficult and it causes severe pain when it descends into a narrow ureter. Therefore, it is desirable to establish a treatment that can be discharged before growing. However, the mechanism of the flow around kidney stones from the upper urinary tract has not been fully investigated, and confirmation by follow-up observation is also difficult. Furthermore, the natural excretion can be difficult from the lower kidney calix because of the gravity. We analyzed flows around a stone by numerical simulation using immersed boundary method. First, the numerical results and the actual experiment were compared with the free fall sphere. As a result, accuracy of the numerical simulation was confirmed. Furthermore, the lower kidney calix model was created based on medical computed tomography images, and the flow of stones was analyzed by numerical simulation.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-9 , 
ISSN:

体外循環流路における血栓形成の電気的計測:(有限要素法によるシミュレーションを使用したコネクタセンサの評価) CiNiiでみる

著者名:
上村 拓生  樫山 昇太郎  川嶋 大介  李 建平  武居 昌宏 

抄録:

Connector-tube interface is where very easily to occur thrombus formation in extracorporeal blood circulating system. For early detection of thrombus formation at the connector-tube interface, connector sensor was developed (by incorporating sensing electrodes on the connector). The aim of this study is to improve the electrode shape of the connector sensor for quantitative evaluation of thrombus. In this study, three types of electrode shapes were devised and evaluated using finite element method (FEM) simulation. The measurement area of each electrode was found from the current density distribution image. Also, simulations were performed with various types of thrombus, and the relationship between the thrombus volume and the change in permittivity was compared to clarify the electrode performance. From these simulations, it was found that the type of connector sensor using two arc-shaped electrodes is most suitable for thrombus quantitative evaluation.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-10 , 
ISSN:

細胞周りの電気二重層に関連したイオン輸送に関する研究 CiNiiでみる

著者名:
川嶋 大介  李 淞什  菅原 路子  小原 弘道  武居 昌宏 

抄録:

出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-7 , 
ISSN:

Optical Coherence Doppler Velocigraphy (OCDV)を用いた再生組織内部における流速分布マイクロ断層可視化法の検討 CiNiiでみる

著者名:
佐伯 壮一  古川 大介 

抄録:

出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-6 , 
ISSN:

未破裂脳動脈瘤治療用多孔薄膜カバードステントの血流抑止能の定量評価:―弯曲親血管における動脈瘤の開口位置が塞栓性能におよぼす影響― CiNiiでみる

著者名:
廣野 充  田地川 勉  中山 泰秀 

抄録:

We have developed a novel microporous covered stent (MCS) for the endovascular embolization treatment of intracranial aneurysm (IA). This stent promotes progressive thrombosis by flow divertion and facilitates IA embolization treatment by clotting of whole blood in the IA. However, difference of geometric configuration of each aneurysms affects the performance. In this study, we investigated intra-aneurysmal flow with various aneurysm position at a curved parent vessel by using in-vitro flow simulator. The IA models were placed at the outer-sidewall at the U-bend parent vessel, of which curvature was as same as that of human carotid siphon. The IA opening position on U-bend vessel was located at θa = 30, 60, 90, 120, 150 and 180 deg. Reynolds number of the parent vessel flow was set at 190 - 970 to simulate CCA blood flow. Microporous sheet (pore diameter: 100μm, aperture ratio: 30%) was placed as a model of a MCS at opening of IA. Flow velocity field at the IA model were measured by PIV. As the results, by MCS stenting, volumetric mean share rate (VMSR) in IA model became about 15 times smaller than before stenting. Dimensionless VMSR was increased proportionally by dimensionless IA in-coming/out-going flow rate increasing. These results suggest that our developed MCS has one of the best embolization device for IA therapy and is expected high embolic effects due to obstruction of direction flow in aneurysm.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-11 , 
ISSN:

浸透圧差によるヒト赤血球の膨潤・溶血挙動:(吸光特性を利用したヘモグロビン濃度変化の可視化) CiNiiでみる

著者名:
米田 悠希  大友 涼子 

抄録:

The osmotic resistance of human erythrocytes under the hypotonic condition is studied. We experimentally observed the swelling and hemolytic behavior of a human erythrocyte caused by a hypotonic solution. The volume change by swelling was approximately estimated from the two-dimensional images of the erythrocyte during the experiments. The results show that the erythrocytes swell until getting spherical shape, and they tend to be reduced in volume and finally hemolyzed. Based on the light absorption characteristics, the mass of the hemoglobin included in an erythrocyte was estimated. Although the hemoglobin mass in an erythrocyte does not change immediately after the hypotonic solution was added, it starts to decrease at a certain time, indicating that the hemoglobin starts to leach out of the erythrocytes due to the hemolysis. The onset time would coincide with the time at which the erythrocyte volume starts to decrease. It is found that the hemoglobin leaching would begin after the erythrocyte getting spherical and it would cause the volume decrease. Additionally, we have attempted to visualize the hemoglobin concentration both in and out of the erythrocyte. The time-dependent concentration change was captured.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-12 , 
ISSN:

感温磁性流体の流れ場計測 CiNiiでみる

著者名:
石井 慶子  相沢 亮汰  麓 耕二 

抄録:

In this study, a new magnetic material was made by microencapsulating the Temperature-sensitive magnetic fluid. Microcapsules are made by dissolving the organic solvent, polymer, Temperature-sensitive magnetic fluid, dropping it into pure water and stirring with a homomixer. Fluorescence observation of particles and visualization of flow field are performed by mixing fluorescent dye in microcapsules. As the results it was confirmed that microcapsules formed clusters by supplying a magnetic field. It was shown that the flow of microcapsule solution can be visualized by using self - made magnetic capsule containing fluorescent dye. The forced convection flow characteristics were investigated using a 1mm×1mm micro channel.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS7-6 , 
ISSN:

臓器移植・再生医療のための機械灌流における流体工学 CiNiiでみる

著者名:
小原 弘道  朱 蔚駿  渡辺 大智  長谷川 海地  二方 幹弥  松野 直徒 

抄録:

出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-14 , 
ISSN:

熱交換器モデル流路内のナノ流体の数値熱流動解析 CiNiiでみる

著者名:
辻中 優哉  山本 剛宏 

抄録:

出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS7-7 , 
ISSN:

小型昆虫を参考にした羽ばたき翼における翼形状の影響 CiNiiでみる

著者名:
加瀬 篤志  野崎 楓  山下 唯人  川口 清司 

抄録:

The small insect, especially the Diptera (for example, fly, mosquito and so on) has a pair of wing and can fly with high mobility and high efficiency. Hence, by consulting the flapping flight of Diptera, it will develop the small flight device which has high flight performance. We focused the planer shape of wing. Then the rectangular wing model whose aspect ratio is agree with that of Diptera wing was treated as the standard model and create some wing model. To study the aerodynamic feature, we performed the numerical simulation of flow around flapping wing by using ANSYS CFX. Then the behavior of the wing model was treated as the immersed boundary by using the "Immersed Solid" function. As results, the following became clear. The average lift force during half stroke is proportional to the squared flapping frequency and the wing area. When the two rectangular wings which have the same wing area were compared the average lift force, the long span wing is higher than the long cord wing. Comparing the mosquito like wing model (Real0) and the rectangle wing (Rect0) which has same cord and span with the Real0, the average Lift and thrust forces per wing area during half stroke were almost same value when the attachment angle of wing model was changed 0 to 60 degrees. Hence, the Real0 has more efficient than the Rect0 from the viewpoint of the generated force per unit area.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-4 , 
ISSN:

サボテンが有する吸水ネットワークの特徴 CiNiiでみる

著者名:
小峰 健矢  窪田 佳寛 

抄録:

Plant gets the good function with the shape of body to survive. In the desert, the cactus needs to realize the saving water in a body and the evaporation of water for the growing. We examined the characteristics shape of cactus and what kind of water absorption network in the stem. We observed the surface of cactus using Scanning Electron Microscope (SEM). Root is similar with other plants. Spines are consisted long spines and short spines. Long spines are shaped like a bundled thin tube and have like a barb. Cactus has stoma on epidermis of the stem for the water absorption. Cactus has no leaf but cactus complement function. The result for path of absorbed in cactus shows that vascular bundle was divided into two when the body is branching. Observed from cross section, conduit extends along the side of stem. One of conduit branches for spines. Spines are connected with conduit. The dye flow visualization shows that the cactus has the mesh-patterned network in a stem. From the graph theory, the network of cactus for water absorption is closely connected and it is consist of nodes with similar function.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-1 , 
ISSN:

Optical Coherence Doppler Velocigraphy (OCDV)を用いた爪郭における血管走行および血流速のマイクロ断層計測法の検討 CiNiiでみる

著者名:
古川 大介  佐伯 壮一 

抄録:

出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-5 , 
ISSN:

MCFゴムセンサを用いた壁面せん断応力の計測 CiNiiでみる

著者名:
宮地 駿弥  窪田 佳寛  望月 修  島田 邦雄 

抄録:

The purpose of this study is the development of an elastic sensor for measuring wall shear stress induced by flow water. We used a flexible sensor by MCF Rubber. MCF is the abbreviation for magnetic compound fluid. MCF Rubber is composed of NR-latex, nickel powder, and magnetic fluid. These materials are mixed, then polymerized with electric heat. The MCF Rubber can measure the force normal to rubber sensor and the shearing force acting on the rubber since the MCF rubber is conductive rubber. The magnitude of the force measured with the change of electric conductivity of MCF Rubber. The change of electric conductivity causes when the deformation of rubber by some time force acting on the MCF rubber. For the consideration of shear stress measurement with MCF Rubber, we used mechanism of a rotational viscometer. Rotational viscometer consists with a rotor rotates by a motor, and the rotor makes a flow in circular container. The wall shear stress can be changed with a rotational velocity of rotor. The strength of wall shear stress can be defined as σ=/2πR3 on Japanese Industrial Standard (JIS). Here, τ is the torque acting on the motor shaft, and R is the radius of rotor. So, the torque converter is installed between the motor and rotor to measure the torque. Six type rotational velocity ranging from 100 to 600 revolution per minute (rpm) to understand the characteristics of MCF Rubber sensor for the wall shear stress measurement. The result shows that the MCF Rubber can measure the change of wall shear stress under the unsteady flow condition.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-2 , 
ISSN:

カヌースラローム競技に向けた艇の自己位置推定手法 CiNiiでみる

著者名:
山田 雄太  窪田 佳寛 

抄録:

ABSTRACT The purpose of this study is the development of a training system for improving technical skills of canoe slalom athletes. One of the most important technique in the canoe slalom competition is the selection of optimal line between the gates. We are trying to visualize the path line of canoe to understand the difference from the optimal line. As the first step to develop the training system, we understand the characteristics of self-position estimation using BLE beacon. The results show the beacon needs to keep the distance less than 1m.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS9-3 , 
ISSN:

Numerical heat transfer study of turbulent square-duct flow through inline V-shaped discrete ribs CiNiiでみる

著者名:
Yu Stu. Shichao  Tsuneyoshi Tatsuya  Yoshihashi Sachiko  Hamaji Yukinori  Ito Takahiro  Tsuji Yoshiyuki 

抄録:

A numerical study has been conducted to examine turbulent flow and heat transfer characteristics in a three-dimensional square-duct with V-shaped ribs. The computations are based on RANS and LES models. Water is the working fluid with the flow rate of which Reynolds numbers equals to 18500. The computation reveals that two symmetrical fully developed helical flow and developed heat transfer profile are generated. Effects of different rib shape on thermal characteristics for a ribbed duct flow are investigated. The change of the shape leads to increase in heat transfer and pressure loss. The velocity profile in the vicinity of ribs and streamline has been investigated, indicates that the different flow structures generated by the rib shape leads to superior heat transfer performance. Vortices are visualized, which indicates the connection between the heat transfer and flow structure


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS8-7 , 
ISSN:

順圧力勾配下に発達する乱流境界層の外層における構造 CiNiiでみる

著者名:
水上 須弥子  鈴木 博貴  望月 信介 

抄録:

Effect of favorable pressure gradient on the similarity in the turbulent boundary layer has been investigated experimentally. In an equilibrium turbulent boundary layer under favorable pressure gradient, mean velocity, Reynolds stresses and wall shear stress were measured and compared with similarities as seen in flat plate boundary layers. The logarithmic mean velocity profile holds in the inner layer under the favorable pressure gradient. Otherwise, the wake component in the outer layer disappears due to the favorable pressure gradient. Turbulent kinematic energy budget is evaluated and compared for zero and favorable pressure gradients. The production and dissipation are almost balanced in the inner layer under zero and favorable pressure gradients. However, the production, dissipation and diffusion terms are reduced in magnitude under favorable pressure gradient. In the intermittency of the turbulent-nonturbulent interface, turbulent region seems to be enlarged due to favorable pressure gradient.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS8-5 , 
ISSN:

透過性メッシュ状境界を用いたチャネル乱流のDNS CiNiiでみる

著者名:
菅野 雅也  横嶋 哲 

抄録:

A series of direct simulations of a fully-developed turbulent flow over a mesh-screen type permeable plate whose geometrical property is systematically changed is performed to identify the relationship between the wall pore structure and the flow characteristics in a wall-bounded turbulent flow. The flow resistance is found to be increased by increasing the porosity of the plate or by decreasing the pore size, and to be closely associated with the blowing/suction intensity through the pores. However, there exists a certain critical pore size, below which the flow resistance is decreased by decreasing the pore size, and the flow goes back to the classical impermeable channel ow. It physically means that, below the critical pore size, the pore is too small for fluid to go through it freely.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS8-6 , 
ISSN:

平板乱流境界層の数値解析を用いたLES壁面モデルの検討 CiNiiでみる

著者名:
三木 悠也  加藤 千幸 

抄録:

In this study, we investigated the wall model for large eddy simulation by using flat plate boundary layer flow simulation. We conducted flow simulation by using different grid resolution, to find out the effect of grid resolution. We showed that the lack of resolution near the wall is affected to the overestimation of the production of kinetic energy. In addition to do simulation, we calculated the correlation between WRLES's instantaneous flow and model's result to evaluate the accuracy of the wall modeled LES by using spalding law as model. We found that there is no correlation between WRLES's data and spalding law's result.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS8-10 , 
ISSN:

乱流境界層中の最大スケール渦はヘアピン状である CiNiiでみる

著者名:
本告 遊太郎  後藤 晋 

抄録:

We examine two datasets of high-Reynolds-number turbulent boundary layers. One is a new dataset obtained by direct numerical simulations on the K computer, and the other is a dataset examined in our previous studies. By using these two datasets, we investigate the shape and sustaining mechanism of the largest-scale vortices in turbulent boundary layers. For this purpose, we identify the largest-scale structures by a coarse-graining method. First, visualizations in physical space show that vortices as large as the boundary layer thickness are hairpin-like. This explains the disappearance of smaller-scale hairpin vortices as the Reynolds number increases. Second, to quantitatively show the dominance of hairpin vortices at the largest scale, we take an average, conditioned by the existence of the low-speed structures at the height of the boundary layer thickness, of the second invariant of the coarse-grained velocity gradient tensor. This simple procedure, indeed, reveals a (largest-scale) hairpin vortex. It is also verified that a low-speed structure is located between the legs of the hairpin vortex.


出版年月日:
2019 , 
巻:
2019 , 
号:
0 , 
ページ:
OS8-11 , 
ISSN: