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Published: September 04, 2010
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Article type: Index
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A1-A8
Published: September 04, 2010
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Masashi ICHIMIYA
Article type: Article
Session ID: J0101-1-1
Published: September 04, 2010
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In order to indicate the complexity of signals in turbulent flows quantitatively, we used a concept of Kolmogorov complexity in computational science. The velocity data was compressed with the use of software for compression. The ratio of data size after compressed one to original one reflects the complexity of the data. Thus we named the ratio "Approximated Kolmogorov Complexity(AK)". First, we checked the validity of AK as the representation of complexity with the aid of simple data. The difference of AK among three compression methods was tested. Then, the present analysis was applied to the laminar-turbulent transition process in a boundary layer. In turbulent region AK showed larger values, on the other hand, in laminar region AK showed smaller values. The existence of a coherent structure close to the wall was suggested.
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Masashi ICHIMIYA, Yasushi FUJIWARA
Article type: Article
Session ID: J0101-1-2
Published: September 04, 2010
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In order to indicate the complexity of signals in turbulent flows quantitatively, we used a concept of Kolmogorov complexity in computational science. The velocity data was compressed with the use of software for compression. The ratio of data size after compressed one to original one reflects the complexity of the data. Thus we named the ratio "Approximated Kolmogorov Complexity". The present analysis was applied to the laminar-turbulent transition process in a boundary layer and compared with the intermittency factor. At turbulent region, the intermittency factor became unity near the wall. On the other hand, the approximated Kolmogorov complexity had a rather smaller value than at y/δ ≒ 0.05. This tendency suggested an existence of the coherent structure of turbulent boundary layer.
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Masashi ICHIMIYA, Shinya KAmADA
Article type: Article
Session ID: J0101-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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In order to indicate the complexity of signals in turbulent flows quantitatively, we used a concept of Kolmogorov complexity in computational science. The velocity data was compressed with the use of software for compression. The ratio of data size after compressed one to original one reflects the complexity of the data. Thus we named the ratio "Approximated Kolmogorov Complexity". The present analysis was applied to the laminar-turbulent transition process in a mixing layer formed at an exit of a two-dimensional nozzle and compared with the randomness factor which has been used for the measure of turbulent transition process in free shear flow. The randomness factor did not vary monotonically since it decreased at first and turned to increase following the progress of turbulent transition. On the other hand, approximated Kolmogorov complexity varied monotonically.
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Koji SHIMOYAMA, Kazuyuki SUGIMURA, Shinkyu JEONG, Shigeru OBAYASHI
Article type: Article
Session ID: J0101-1-4
Published: September 04, 2010
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This paper proposes and demonstrates the construction of performance maps, which represent relations between various performance and geometry parameters, with the aid of data mining techniques. Data mining can reveal characteristic patterns in high-dimensional data with performance and geometry parameters. Therefore, the data mining results make it easy to interpret complex features of performance vs. geometry relations, and help engineers to discover new knowledge for engineering design through interpretation. The present demonstration of a centrifugal diffuser demonstrated that the data mining techniques are suitable and applicable to high-dimensional performance map construction, together with actual acquisition of new knowledge for diffuser design that was unknown from conventional quasi-one-dimensional nozzle theory.
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Yuta KONDO, Hiroyuki FURUKAWA
Article type: Article
Session ID: J0101-2-1
Published: September 04, 2010
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In a study, we focus on "edge effect" of the rotating disk in a cylindrical container. The gaps of the radial and axial directions between the casing base and the rotating disk cause a great influence on the flow in the container. This is called "edge effect". In this study, we used different sizes of the rotating disks, and changed the size of gaps in the radial and axial directions. The influences of the gap to the flow near the fixed container are investigated. As a result, "bead-like vortex" is observed between the rotating disk and the container. The appearance of bead-like vortices depends on the gap length in the radial direction.
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Akihiro KAWAGUCHI, Hiroyuki FURUKAWA
Article type: Article
Session ID: J0101-2-2
Published: September 04, 2010
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In previous studies of a flow caused by a rotating disk in a casing, the geometry of a rotating disk is not considered significantly. Recent studies unveil that a gap of radius direction has an great influence on a flow between a casing base and rotating disks. In this study, we used some kind of rotating disks, and investigate about the influence of a radius direction gap to a flow near the fixed disk. As a result, we confirm that the difference of disk geometries cause different "Front angle" in each disks. Our experimental study analyze "Front angle" in detail.
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Takashi WATANABE, Hiroyuki FURUKAWA
Article type: Article
Session ID: J0101-2-3
Published: September 04, 2010
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Flow around a rotating disk in a cylindrical casing is numerically and experimentally investigated. While the disk is thick and the axial gap is narrow, the radial gap between the disk rim and the shroud of the casing is large. In this case, Taylor-Couette vortex like flow appears in the radial clearance. When the rotating speed is moderate, the vortex flow is wavy and has some disturbances. The thinness of the axial gap prohibits the penetration of the disturbances into the inner region. Instead, a bead-like flow and a sickle-like vortex flow appear.
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Yuriko TAKESHIMA, Takashi TOKUMASU, Issei FUJISHIRO
Article type: Article
Session ID: J0101-2-4
Published: September 04, 2010
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In visual analysis, it is important to maintain interactive and stable rendering framerates, because it is known that unstable framerates may cause stress and distraction problems to the users. For stabilizaing framerates in large-scale particle visualization, we deploy a fast rendering method based on shaded texture mapping and a high-quality method using implicit surfaces in a combined manner. Actual rendering method for each particle is decided on the fly according to the measured distance between the center of the particle and the viewpoint. We propose a framerate stabilization scheme using PID control, which dynamically changes the switching-distance to control the number of particles rendered by each method. We illustrate how well our dynamic framerate stability control works through experiments with practical molecular dynamics simulation datasets.
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Susumu SHIROYAMA
Article type: Article
Session ID: J0101-2-5
Published: September 04, 2010
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As complexity of computational/experimental raw data in fluid dynamics increases, methods or methodologies to extract useful information from such data have been studied from various standpoints. However, most of them are based on high-performance computing techniques or highly-efficient devices for computer graphics. Although such studies have succeeded in visualizing ultra-scale data, several issues remain unsolved. In this paper, a flexible visualization methodology based on "analysis of visualization process" is introduced. A possibility that a visualization agent designed from a process model helps to reduce the difficulty of handling huge data is described.
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Noritaka SUZUKI, Gou TANAKA, Hiroyuki FURUKAWA
Article type: Article
Session ID: J0101-3-1
Published: September 04, 2010
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Taylor vortex flow between two concentric rotating cylinders appears in a journal bearing or the chemical reactors. It is useful in the engineering point of view to analyze the behavior of the flow. The governing parameter of the flow are the aspect ratio and Reynolds number. The aspect ratio of the cylinder height to the gap between the inner and outer cylinders. Reynolds number is defined using the speed of the inner cylinder. In this study , Taylor vortex flow at small aspect ratio is analyzed by using PIV method. The flow structure is investigated quantitatively. The PIV results are compared with the results obtained by the numerical method.
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Tsuyoshi WATANABE, Hiroyuki FURUKAWA
Article type: Article
Session ID: J0101-3-2
Published: September 04, 2010
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Taylor vortex flow appears between two concentric rotating cylinders, for example, fluid bearings of hard disks etc. It is important to investigate Taylor vortex flow in order to control flows. When the velocity of inner cylinder changes, the flow suddenly becomes unstable and develops into vortex flow having different number of cells. Cylinder torque applied to the cylinder walls and mean kinetic energy change sharply, and it leads to the deterioration and destruction of the container. The boundary layer of the end plane affected to the entire flow. In this study, we change the boundary condition of the end plane, and analyze the influence to the bifurcation diagram. When Raynolds number is decreased, the bifurcation occurs.
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Yorinobu TOYA, Takashi WATANABE
Article type: Article
Session ID: J0101-3-3
Published: September 04, 2010
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This study is concerned with a bifurcation relationship between Taylor vortex flow and wavy Taylor vortex flow. We used three-dimensional numerical calculation. Our concern is a criterion for the estimation of the critical Reynolds number at which the wavy Taylor flow bifurcates to the Taylor flow. We calculated the spatially averaged energy of the bottom vortex of the flow. Before the estimation of the critical Reynolds number, we had to find the criterion for the judgment of the Taylor flow and the wavy Taylor flow. Then we checked the amplitude of the variation of the energy. From the result of the width of the amplitudes of the variations of the energy around the critical point, we established the width of the variation of the energy 0.001 as the standard value. And then we measured the critical Reynolds number between the Taylor flow and the wavy Taylor flow with aspect ratio. Finally the numerical results are compared with the experimental results.
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Shohei FUJISAWA, Takashi WATANABE, Yorinobu TOYA
Article type: Article
Session ID: J0101-3-4
Published: September 04, 2010
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The onset flow developing between a rotating inner cylinder and a stationary outer cylinder is investigated by the numerical approach. The both ends of the cylinders are stationary. Reynolds number that controls flow is decided from circumferential velocity of the inner cylinder and width between two cylinders. In the initial state, the flow remains stationary in the whole area, and it is assumed that the inner cylinder accelerates rapidly until a constant Reynolds number is attained. The Ginzburg-Landau equation and the solution are proposed to one of the models when the flow develops. This is a model of flow development of the time dependent disturbance when a spatially infinity is assumed. In this study, this model is adopted and the quantitative evaluation that how proper the model is for the flow between two rotating cylinders with finite lengths.
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Hidetoshi TAKAHASHI, Kiyoshi MATSUMOTO, Isao SHIMOYAMA
Article type: Article
Session ID: J0205-1-1
Published: September 04, 2010
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This paper reports on direct measurement of differential pressure on a butterfly wing during free flight. Differential pressure was measured using a micro-fabricated sensor. A piezo-resistive cantilever was used as a differential pressure sensor. The sensor was 1.0 mm × 1.0 mm × 0.3 mm in size and 0.7 mg in weight so that it did not interfere with wing motion. By attaching the sensor to the center of a butterfly forewing with a flexible wiring, the differential pressure on the wing was measured during free flight. We revealed that the maximum pressure value was 11.7 Pa at the end of stroke. The maximum aerodynamic force in free-flight is 10 times as large as the gravity acting on the body.
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Shou WATANABE, Akihisa KONNO, Satoshi TERADA
Article type: Article
Session ID: J0205-1-2
Published: September 04, 2010
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To investigate mechanism of three-dimensional flapping propulsion for a fishlike underwater vehicle, calculation method of flow field around three-dimensional wing with flapping and pitching motion is developed. We use OpenFOAM CFD software and develop a routine to represent three-dimensional, flapping and pitching motion of a wing with arbitrary amplitude and phase difference. Calculation under laminar flow condition is conducted; Reynolds number is 1000 and NACA0018 rectangular wing is used. Both flapping and pitching amplitude is 0.25 rad/s, phase difference π/2 rad, and C-shape grid is used. The result suggests that our method can investigate the flow field around three-dimensional flapping wing.
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Chikara KANAZAWA, Toshiyuki NAKATA, Yoshinobu INADA, Hiroyuki KATO, Ha ...
Article type: Article
Session ID: J0205-1-3
Published: September 04, 2010
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Research and development of Micro Air Vehicles (MAVs) aiming at the investigation and the information gathering in the hazard area is now an active field. Flapping flight of insects and birds that are capable to perform precise hovering flight and to make rapid turn and maneuver steadily in sudden gust has been attracting specific attentions in the last decades. In this study, in order to validate a biology-inspired dynamic flight simulator that is designed to model realistic flapping-wing flights and to evaluate novel mechanisms in bio-flights, we conducted measurements and analysis of low Reynolds number unsetady flows around a flapping-wing robot "MOTH-1" by utilizing PIV techniques in a wind tunnel (JAXA). Our PIV results have thereby confirmed the strong leading-edge vortices and the vortex rings as predicted in our previous simulation study.
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Tadatsugu IMURA, Masaki FUCHIWAKI, Kazuhiro TANAKA
Article type: Article
Session ID: J0205-1-4
Published: September 04, 2010
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Micro-Air-Vehicle (MAV) using insect and bird flight mechanisms have been researching all over the world in recent years since the micro-electro-mechanical systems (MEMS) have been developed. Many researchers have developed MAV with various actuators and devices however their MAV have not been put to practical use yet. One of the reasons is that flying mechanism of birds and insect has not been clarified sufficiently. In this study, the authors developed the micro flapping robot used insect and bird flight mechanisms. The micro flapping robot has two wings which have the proper elasticity and do not have tail plane. The proper elasticity of wing realizes elastic deformation in the trailing edge of wing. The wing deformation of micro flapping robot realizes stable body angle in a flight and a stable flight for 15 minutes which was the battery's duration.
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Rina NEMOTO, Satoshi NISHIMOTO, Yoshiyuki KAWAMURA, Koji ISOGAI
Article type: Article
Session ID: J0205-1-5
Published: September 04, 2010
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In this study, we have developed synchronized continuous stroboscopic photography with high resolution for observation of the moving membrane wing. We also have developed a calculation program for the analysis of the results obtained using DLT (Direct Linear Transformation) method for motion analysis of 3-demensions. We have successfully applied measurement results obtained by the method described above to CFD (Computational Fluid Dynamics) program.
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Kiyotaka YAMAMOTO, Hiroki SHIBATA, Yoshiyuki KAWAMURA, Teruo TSUJI
Article type: Article
Session ID: J0205-1-6
Published: September 04, 2010
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Recently, the research of MAVs (Micro Air Vehicles) is advanced because of the miniaturization of the motor and the battery. There are the features that flapping-MAV is strong to the gust and able to hover. It is important to observe the aerodynamic characteristics of the flight of MAVs without support rod in case of flapping MAVs. In the development of the flight experimental system in a wind tunnel, we have succeeded in the stable flight by fixed-wing MAV as an initial stage. We developed the flight system with feedback control using image device which consists of two CCD cameras and image processing device to measure the position and yaw angle of the MAV.
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Akinori SATO, Toshiyuki NAKATA, Hao LIU
Article type: Article
Session ID: J0205-1-7
Published: September 04, 2010
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This paper describes the evaluation of aerodynamic performance of insect-inspired flapping wings for MAVs design. The insect-inspired wings are made of stiff leading edges and flexible membranes so as to employ the passive wing deformations due to inertial and aerodynamic forces in terms of feathering and camber. In this study, the effect of wing stiffness on the aerodynamic performance of flapping micro air vehicle is investigated. The wing stiffness is realized by attaching ribs on the wing surface and tape on the trailing edge of the wings. The wings are attached to a prototype MAV, which is designed to employ the "clap and fling" mechanism with four wings cross between. The thrust force on the flapping wings is further measured to evaluate the aerodynamic performance of the MAV. The experimental results indicate that the wing stiffness to achieve the maximum thrust depends on the flapping frequency. When the flapping frequency is high, the thrust force increase with the wing stiffness. In experimental range of this study, the wings that have higher stiffness showed high performance at more than 18Hz. This result shows that the stiffness of flapping wing is an important factor for the design of MAV.
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Shotaro YOSHIDA, Daisuke ISHIHARA, Takanori SHIMURA, Tomoyoshi HORIE, ...
Article type: Article
Session ID: J0205-2-1
Published: September 04, 2010
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In this study, we evaluated passive pitching motions and lift force during flapping flights of three diferent Dipteras using the dynamically scaled model. Since the wing and the surrounding fluid interact with each other, the dynamic similarity between the model and the insect flight was measured using not only the Reynolds and Strouhal numbers but also the mass and Cauchy numbers. Our model includes the plate spring to simulate the low torsional stiffness of the insect wing. Our model simulated the pitching motion similar to the actual insect and generated the enough force to lift the insect.
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Naoki TAKAGI, Masao FUKASE, Kazutaka KITAGAWA, Yasue TANAKA, Koichi OK ...
Article type: Article
Session ID: J0205-2-2
Published: September 04, 2010
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Recently, the unsteady aerodynamics of flitting flights for birds and insects has attracted the interest of many researchers. They take aerodynamics property of flapping flight as research for a bat, a bird, a dragonfly, a mosquito, a bee and a butterfly, etc. The present work is aim to investigate the flapping flight of small beetle such as Anomala japonica. The flapping motion and flow field of wing are visualized with high speed video recording, dynamic PIV and CFD. Measured flapping frequency is about 71Hz. Anomala japonica has six phases of wing motions, feathering, clap and filing, lead-lug, upstroke and downstroke processes.
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Ayumi FUJITA, Tasuku MIYOSHI
Article type: Article
Session ID: J0205-2-3
Published: September 04, 2010
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The purpose of this study is to develop a Micro Air Vehicle based on an insect's flapping motion that can be used as an explorer in special environments. We constructed the prototype mechanism of the flapping motion by using the elastic deformation of the exoskeleton and applying the principle of leverage. In this mechanism, the vibration generated from the solenoid was transmitted to the exoskeleton, and the wing was moved indirectly. The phosphor bronze, 0.2mm in thickness, was used to form an exoskeleton frame and the wing rods. This mechanism enabled two degree of freedom of movement. In this paper, we compared the flapping and feathering motions of the prototype compared with those of the natural insect.
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Satoshi NAGAI, Shinya KOSEKI, Hiromu HAHSIMOTO
Article type: Article
Session ID: J0205-2-4
Published: September 04, 2010
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The purpose of this study is to clarify the dragonfly's aerodynamic characteristics. The dragonflies have excellent flight ability such as high-speed flight and hovering flight. But we can't design the flying machine like dragonflies according to conventional laws of aerodynamics. The flying law is very difficult to understand because it is coupled problem about flutter motion, surface structure and elastic deformation of the wings. So we characterize an aerodynamics by visualization experiment. In this paper, we investigated the aerodynamic characteristic of the surface structure of the wings. Dragonflies have characteristic surface structures of the wings such as nervure and reticulation. We made the artificial wings imitated their surface structures, and the characteristics were clarified by the experiment.
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Naoshi NISHIHASHI, Kenichi TSUBOTA, Hao LIU
Article type: Article
Session ID: J0205-2-5
Published: September 04, 2010
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Here we present a study on three-dimensional shape optimization of flapping wings. A vertical force maximization problem for insect flight is formulated in the domain of unsteady-state, low Reynolds number viscous flow field. Adjoint method, a type of sensitivity analysis based on the variational principle, is modeled by the Navier-Stokes equations and discretized with the finite volume method. With the method, shape optimization of the wings of a model fruit fly in hovering flight is attempted. Rectangles, having both the aspect ratios and the surface areas identical to those of the realistic wings, are taken as the initial shapes. As a result, their sensitivities to the shape modifications are derived.
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T. Ishikawa, N. Yoshida, H. Ueno, N. Matsuki, Y. Imai, T. Yamaguchi
Article type: Article
Session ID: J0205-3-1
Published: September 04, 2010
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Kouhei KASAHARA, Tonau NAKAI, Tomonobu GOTO
Article type: Article
Session ID: J0205-3-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Rotating helices are often found as flagella, organs of locomotion, in microorganisms and they are expected to be useful as screws or pumps in the flow of very low Reynolds number. When a helix is rotated by a torque along its helical axis, a propelling force is generated as a reaction of the force exerted on the surrounding fluid by the helix. In this study, we considered the ratio of the propelling force to the input torque as a measure of the efficiency of the helix, and numerically investigated the shape of the helix which maximizes the ratio. The boundary element method was employed to calculate the force and torque. According to our results, the most efficient helix has the wavelength of tenth of the filament's diameter, the pitch angle of 30 degrees, and the number of turns of around 1.
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Takuya INOUE, Tonau NAKAI, Tomonobu GOTO
Article type: Article
Session ID: J0205-3-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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We experimentally investigate three-dimensional swimming trajectories of bacteria near a surface. In order to measure the position of depth direction of the view, we elucidated the relationship between apparent color of the bacteria and distance from the focal plane. Distance between bacteria and the focal plane was successfully deduced as a function of gradation value in gray scale. By using this relationship, we measured the curvature of trajectories in bacterial swimming which is hydrodynamically affected by a surface. It results in more influence of a rigid surface on the bacterial swimming than a free surface.
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Katsuya KUGAI, Ryuichi HAMAGUCHI, Tomoaki NAKAI, Yuya SAKAGUCHI
Article type: Article
Session ID: J0205-3-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The swimming motion of Tuna type fishes has excellent ability for its speed and efficiency. In the former study, propulsive force of tale fin is estimated from experimental data of lift and drag force by using 1/1 scale tale fin model. Additionally, drag force of tuna body is also measured by using 1/1 scale body model. This paper shows how to design the tale fin driving architecture to realize fastest swimming robot. The difference of this driving architecture is independent two motor. One drives tale fin oscillating motion, and another drives tale fin angle. So, this robot can verify the efficiency of swimming motion in preceding study and our study.
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Yukio OHKUBO, Akihisa KONNO, Shinichiro ITO, Koichi HIRATA, Yoichi NIK ...
Article type: Article
Session ID: J0205-3-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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A fishlike autonomous underwater robot was developed. Three infrared distance sensors and a microcomputer circuit are built into the robot. These systems can detect obstacles and the robot can perform evasion movement. This robot has two actuators: a caudal fin and a pectoral fin. Motion of a caudal fin with the phase difference is realized by using a special mechanism. Experiments were carried out to observe the robot performance of obstacle avoidance. As a result, the robot could avoid the obstacles by turning and ascending movements.
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Shingo SUZUKI, Motomu NAKASHIMA, Kenji NAKAJIMA
Article type: Article
Session ID: J0205-3-6
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The objective of this study was to develop a simulation method for monofin swimming which can consider the mechanical interaction between the monofin and swimmer. For this objective, SWUM (Swimming Human Simulation Model) was extended to the monofin swimming. The body geometry and joint motion of the swimmer were aquired from the experiment using a subject swimmer. In order to identify the bending stiffness and damping coefficient of the monofin, the static and dynamic bending tests of a monofin were conducted. In order to identify the fluid force coefficients of the monofin, the fluid force acting on the monofin was measured in the experiment. From the simulation of monofin swimming using the identified model parameters, it was found that the whole behavior of the swimmer and monofin in the simulation agrees well with that in the experiment.
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Shun MAEDA, Motomu NAKAJIMA
Article type: Article
Session ID: J0205-3-7
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The objective of this study was to optimize the crawl stroke by the computer simulation. For this objective, the Particle Swarm Optimization was incorporated into our swimming human simulation model SWUM. With respect to the constrained condition, the maximum joint torque characteristics for the shoulder and elbow joints were imposed. In order to acquire these characteristics, the musculoskeletal simulation for the upper limb was employed. From the result of optimization, it was found that the optimized stoke was close to the so-called S-shape stroke.
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Ryosuke MORI, Hirohisa MORIKAWA, Shunichi KOBAYASHI, Motomu NAKAZIMA, ...
Article type: Article
Session ID: J0205-4-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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It is known that a dolphin swims fast and freely in water. The propulsive performance and the kinetic performance of the dolphin are one of great concerns among researchers. We paid attention to the dolphin's tail flukes which had an important role to generate a propulsive force. The swimming behavior of the dolphin which lost most part of its tail flukes by diseases was investigated when an artificial tail fin was attached to the dolphin's. The propulsive forces were obtained by using data on the behavior of the tail fin. The effectiveness of artificial tail fin was discussed.
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Hidetake YAMAMOTO, Tsukasa KOBAYASHI, Nobuaki TAKAHASHI, Yusuke KAKUNO ...
Article type: Article
Session ID: J0205-4-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This research purpose is development of the bioinspired intelligent materials applying biphasic composition of biocompatible piezoelectric rubber multicellular structures and inert gas in order to create the multifunctional effect of the solid-fluid dynamic dispersion for cancellous bone and the impact shock absorption and the piezoelectricity for fibrous tissues such as muscles. This is the first paper reporting on manufacture of the two-dimensional model for rubber multicellular structures to constitute active shock absorption due to the biphasic composition and measurement of the viscous elastic in-plane deformation of its hexagonal cell units. Quasistatic in-plane indentation properties of the urethane rubber hexagonal cells depended on the rubber's viscous elasticity at the speeds from 0.1 to 100 mm a minute. As for the multicellular structure built of urethane rubber hexagonal cells, the in-plane indentation to the central cell on the top cell-layer at the speed of 10 mm a minute illustrated the bottom cell-layer's load distributions based on the in-plane anisotropy of multicellular deformation.
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Kenji KIKUCHI, Seiji ICHIKAWA, Osamu MOCHIZUKI
Article type: Article
Session ID: J0205-4-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The purpose of our study is to know the interaction between a flow and a surface of hydro gel. Tissue of living organ like blood vessel, cartilage and eyeball is a hydro gel. It contains water, so that the surface of hydro gel is considered to be water. Thus, it is a hydrophilic material. We expect it to show good reduction of friction if we use it the wall of a conduit. To check the concept, we measured velocity profile of a film flow on the hydro gel by a micro PIV method, estimating wall share stress from the velocity gradient at the wall. We confirmed slip-velocity depending on degree of swelling of hydro gel and the flow inside of gel induced by shear stress.
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Tetsuya YANO, Masayoshi SAKAI, Seiichi SUDO
Article type: Article
Session ID: J0205-4-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Recently, many researchers have been developing the various types of micro aerial vehicles (MAV). These developments are conducted on the basis of the computational and experimental fluid dynamics studies. We believe that the findings from the winged seed of plants would serve useful information for the development of such aerial vehicles. In this study, we investigated the gliding performance of the winged seed of Alsomitra macrocarpa. Furthermore, the microasperity structure on the surface of the seed was observed and measured using the conforcal laser microscope.
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Takaaki SATO, Hitoshi MIYAKE
Article type: Article
Session ID: J0205-4-6
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Various biomimetics had been analyzed and utilized in various fields. The muscle spindle is an invaluable displacement sensor in the living body. It is able to change resolution and to adjust sensitivity. In this paper, a new biomimetics tension sensor which has the characteristic muscle spindle and skeletal muscle structure and function was developed. The biomimetic tensiometer was created by fixing the piezo actuator as intrafusal muscle fiber mimetics and strain gauge. The muscle spindle mimetics consisted of the piezo actuator and the strain gauge and elastic component. The tensiometer utilized the muscle spindle mimetics and the skeletal muscle mimetics proportional variable length. Consequently a proportional variable length tensiometer was developed.
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Shinji MATSUSHITA, Yasuhiro INOUE, Masaki HOJO, Masahiro SOKABE, Taiji ...
Article type: Article
Session ID: J0206-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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It is essential to investigate the nanomechanical behavior of cytoskeletal actin filaments in order to understand their critical role as mechanical components in various cellular functional activities. These actin filaments consisting of monomeric molecules function in the thermal fluctuations. Hence, it is important to understand their mechanical behavior on the microscopic scale by comparing the stiffness based on thermal fluctuations with the one experimentally measured on the macroscopic scale. In this study, we perform a large-scale molecular dynamics (MD) simulation for a half-turn structure of an actin filament. We analyzed its longitudinal and twisting Brownian motions in equilibrium and evaluated its apparent extensional and torsional stiffness on the nanosecond scale. Upon increasing the sampling-window durations for analysis, the apparent stiffness gradually decreases and exhibits a trend to converge to a value that is close to the experimental value.
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Yasuhiro Inoue, Shunsuke Tsuda, Taiji Adachi, Masaki Hojo
Article type: Article
Session ID: J0206-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Actomyosin contractility is a major force-generating mechanism that drives rearrangement of actomyosin networks; it is fundamental to cellular functions, such as cellular reshaping and movements. Thus, to clarify the mechanochemical foundation of the emergence of cellular functions, understanding the relationship between actomyosin contractility and rearrangement of actomyosin networks is crucial. For this purpose, in this study, we present a new particulate-base model for simulating the motions of actin, non-muscle myosin II, and α-actinin. We simulated the dynamic rearrangement of actomyosin networks. Our simulation results indicate that an increase in the density fraction of myosin induces a higher-order structural transition of actomyosin filaments from networks to bundles, in addition to developing the force generated by actomyosin filaments in the network. On the basis of our results, we describe the mechanical and biochemical roles of a-actinin in sustaining the network and a positive feedback loop observed in the formation of actomyosin bundles.
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Yohei NANAZAWA, Noriko TAMURA, Shinya GOTO
Article type: Article
Session ID: J0206-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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We develop a basic model of platelets as a cell forming thrombi. In the model, the platelet intracellular reaction is produced by the contact of the platelet with a vessel injury area. According to this reaction, adhesions and agglutinations of the platelet occur. In this report, we focus on the filamentous existence caused by bonding GPIba and VWF and verify it.
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Makoto SAITOH, Shigeru AOMURA, Hiromichi NAKADATE, Yuelin ZHANG, Satos ...
Article type: Article
Session ID: J0206-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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When the human head is loaded by the rotational impact, a diffuse axonal injury (DAI) is caused in human brain. DAI is caused by the shear strain and shear strain rate that arises at the brain stem when the head does the rotation movement by the angular acceleration. However, the influences on the shear strain and shear strain rate by the change in parameters of the angular acceleration were not described. In this study, various accelerations that differs parameters were given to a human head finite element model, the influence on the shear strain and shear strain rate caused on the brain stem was considered. In this report, rise time of angular acceleration was focused on. As the result, the change in rise time did not influence the shear strain so much. But the change in the rise time greatly influenced the shear strain rate.
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Seishin TAKAO, Shigeru TADANO, Hayato SUZUKI, Hiroki SHIRATO
Article type: Article
Session ID: J0206-1-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Radiotherapy shrinks solid tumors by irradiating cancer cells. Radiation effects on genes in cancer cells and causes apoptosis or arrest of cell cycle by changing patterns of protein expression. If it is possible to know about the tumor protein and enzyme reactions, more effective treatment would be performed. In this study, based on the concept of systems biology, we aimed to simulate the reaction mechanism of cancer cells in cell cycle to radiotherapy. Main agents of cell cycle machinery are cyclin, cyclin dependent kinase (CKI) and CDK inhibitor (CKI). Various cyclins are produced in each of cell cycle phases and configure complexes with particular CDK. These complexes promote cell cycle. Meanwhile, CKIs inhibit cell cycle by inactivating the cyclin-CDK complexes. This study modeled interactions among these agents and simulated sequential progression of cell cycle in normal cells. Based on the normal cell cycle model, cancer cell cycle model and radiotherapy model were constructed by modifying expressions of control agents. Simulation results showed that each cyclin-CDK complex was activated at appropriate time in normal cell cycle model, suggesting that cell cycle proceeded properly. In radiotherapy model, cell cycle did not progress because particular cyclin-CDK complexes did not progress due to expression of p53 gene. From the above results, the model proposed here seems to be suitable to simulate cell cycle progress.
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Kohei OKITA, Nicolas LEDUC, Kazuyasu SUGIYAMA, Shu TAKAGI, Yoichiro MA ...
Article type: Article
Session ID: J0206-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Although nowadays widely spread for imaging and treatments uses, HIFU techniques are still limited by the distortion of the wave front due to refraction and reflection over the inhomogeneous media inside the human body. CT-scan Time Reversal (TR) procedure has risen as a promising candidate for focus control. A finite difference time domain parallelized code is used to provide simulations of TR-enhanced propagation through elements of the human body and implement a simple algorithm to address the issue of grating lobes, or pressure secondary peaks due to natural diffraction of phased array and enhanced by medium heterogeneity. Using an iterative, progressive process combining secondary sound sources and independent signals summation, the primary peak is strengthened while secondary peaks are increasingly obliterated. This method supports the feasibility of precise modification and enhancement of the pressure profile in the targeted area through Time Reversal based solutions.
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Takaaki SHIMURA, Kohei OKITA, Shu TAKAGI, Yoichiro MATSUMOTO
Article type: Article
Session ID: J0206-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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In current High Intensity Focused Ultrasound (HIFU) simulation, the influence of the transverse wave due to the elasticity is not taken into account. To examine the effect of the elastic body on the focusing of ultrasound, we developed the fluid-elastic coupled calculation code which can treat inhomogeneous media such as human cells, bones, and organs, where the linear elastic body is assumed for bones and organs. The numerical method is based on the FDTD method. The calculation of the focusing ultrasound through a elastic plate results that the intensity of ultrasound in the elastic plate becomes lower than that in the fluid plate which neglects the transverse wave.
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Fuyou LIANG, Shu TAKAGI, Shigeho NODA, Hao LIU, Marie Oshima
Article type: Article
Session ID: J0206-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Definition of boundary conditions is a crucial step in three-dimensional (3-D) hemodynamic computation. An improper treatment of boundary conditions may result in misleading predictions no matter how precisely the geometric model has been constructed. In consideration of the fact that any arterial segment belongs to the cardiovascular system, a reasonable means of getting rid of difficulties in boundary condition definition is to place a 3-D hemodynamic model into a model which represents a broader cardiovascular area. In this study, we develop a multi-scale model by coupling models of dimensional levels. The model integrates 3-D flows, arterial wave propagation and global hemodynamics into a unique computational system. Benchmark tests demonstrate that the model is able to reasonably describe hemodynamic phenomena in various physiological conditions.
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