In the present study, we have attempted to investigate a feasibility of exhibiting a significant trapping performance by means of multi-pairs of magnetic poles. We here focus on the two representative types of configurations using two pairs of magnetic poles. That is, the first is a vertical configuration of two pairs of magnetic poles, where each pair of magnetic poles is arranged perpendicular to the flow direction, and the second is a parallel configuration, where each pair of magnetic poles is arranged along the wall surface of a circular cylinder. As in the previous study for one pair of magnetic poles, we have here investigated the behavior of magnetic rod-like particles in a Hagen-Poiseuille flow, by means of Brownian dynamics, in the above-mentioned two pairs of magnetic poles, which induce magnetic forces to function to trap magnetic particles around the magnetic poles. In the case of the vertical arrangement of the two pairs of magnetic poles, a largely-packed aggregate is trapped between the first pair of magnetic poles, and this trapping characteristic is reproduced between the second pair of magnetic poles. In this case, these large clusters are mainly formed in the center area of the cylinder perpendicular to the flow direction. In contrast, for the case of the parallel arrangement, a largely-packed cluster is formed between a pair of magnetic poles and located along the wall surface. Different from the previous arrangement of magnetic poles, this largely-packed cluster may sufficiently survive and be trapped between the poles by shifting the position nearer to the wall surface. From these results, we suggest that the parallel arrangement of magnetic poles gives rise to a better trapping performance.

We develop a method to simulate fluid flow near a road tunnel portal with driving cars using an open-source computational fluid dynamics solver OpenFOAM. We employ sliding mesh and Arbitrary Coupled Mesh Interface (ACMI) functionality to realize motion of cars relative to the tunnel. We also employ mapping functionality to realize continuous simulation; the result of simulation with sliding mesh is mapped to the following step of simulations as the initial flow field. Boundary conditions for interface between fixed and sliding meshes are discussed. 2-dimentional flow fields near the tunnel portal with or without driving cars are simulated successfully.

Recently MPFI(Moving Particle Full-Implicit) is advocated as an analytic method for the high viscous fluid flow with the free surface. But there are still few quantitative evaluations about its utility. I expanded MPFI method into 3D and wall boundary model without using wall particles. I held simple validation cases of the hydrostatic pressure and the Hagen-Poiseuille flow, and also held cases of liquid rope coil to check the conservation of angular momentum and got satisfactory results.

Measurement of velocity profile of a fuel jet bifurcating inside a diffusion flame under acoustic excitation is conducted by means of particle tracking velocimetry. It is confirmed prior to the detailed examination that the addition of particles to the fuel gas has negligible effect on the behavior of the jet, and that the measured velocity by this method is reasonably accurate. The results indicate that the velocity profile is not altered by the acoustic forcing in the region in which shadowgraphy shows the jet going straight before meandering. This infers that the bifurcating behavior is originated from not the effect of steady streaming but that of linear instability. On the other hand, the velocity profile oscillates synchronically with the acoustic forcing in the region in which the shadowgraphy shows the jet meandering. A qualitative explanation of the bifurcation of the jet is successfully obtained by considering the probability density distribution of the oscillating fuel jet based on the interpretation of the experimental results.

In the present study we have attempted to investigate a feasibility of exhibiting a significant tapping performance by means of multi-pairs of magnetic poles. We here focus on the two representative types of configurations using two pairs of magnetic poles. That is, the first is a vertical configuration of two pairs of magnetic poles, where each pair of magnetic poles is arranged perpendicular to the flow direction, and the second is a parallel configuration, where each pair of magnetic poles is arranged along the wall surface of a circular cylinder. As in the previous study for one pair of magnetic poles, we have here investigated the behavior of magnetic rod-like particles in a Hagen-Poiseuille flow, by means of Brownian dynamics, in the above-mentioned of two pairs of magnetic poles, which induce magnetic forces to function to trap magnetic particles around the magnetic poles. In the case of the parallel arrangement, a largely-packed cluster is formed between a pair of magnetic poles and located along the wall surface. Different from the previous arrangement of magnetic poles, this largely-packed cluster may sufficiently survive and be trapped between the poles by shifting the position nearer to the wall surface. Appropriate conditions of the magnetic particle-particle interaction strength, the applied magnetic field strength, the separation distance between a pair of magnetic poles, etc., give rise to a better trapping performance in the parallel arrangement of magnetic poles.

This paper aims to investigate flows in a model of microscopic lymphatic vessels of mice for developing noninvasive cancer treatments. The model consists of an axisymmetric tube with its diameter changing linearly along the axis, called a tapered tube. Reynolds number of the flow is assumed to be much smaller than unity because the tube diameter and the flow velocity are small. Continuity equation and Navier-Stokes equations are solved in an analytical manner based on the Stokes approximation. Solutions of the velocity and pressure are represented in nondimensional forms. The friction coefficient of the flow is expressed in a simple form for convenience of applications.

To improve computation efficiency of Molecular dynamics (MD) method dramatically, we developed Renormalized molecular dynamics (RMD) method. This method makes it possible to decrease the number of particles whilst maintaining macroscopic phenomena at similarity. We carried out polymer simulation by using RMD method and have succeeded in replicating several particular phenomena of viscoelastic fluids.

This paper presents a numerical solution to shape optimization for elastic fields considering Fluid-Structure Interaction (FSI). The mean compliance minimization problem in order to achieve stiffness maximization on elastic fields is formulated on volume constraint condition. The shape gradient of the shape optimization problem is derived theoretically using the adjoint variable method, the Lagrange multiplier method and the formulae of the material derivative. Reshaping is carried out by the traction method proposed as an approach to solving shape optimization problems. Numerical analyses program for the shape optimization is developed based on FreeFem++, and the validity of proposed method is confirmed by results of 2D numerical analyses.

In the present study, we have elucidated the behavior of a suspension composed of magnetic disk-like particles that flow in a Hagen-Poiseuille flow in a gradient magnetic field and the trapping characteristics of the magnetic particles by means of multi-pairs of magnetic poles. Brownian dynamics simulations were performed in order to clarify the dependence of the trapping characteristics on a variety of factors such as the magnetic interaction between particles, the strength of a non-uniform magnetic field, the strength of the flow field and the separation distance between two pairs of magnetic poles. The main results obtained here are summarized as follows. An increase in the magnetic field strength improves the trapping characteristics of disk-like particles if the influence of an applied magnetic field is sufficiently more dominant than that of a flow field and also that of the magnetic particle-particle interaction. In the case of a strong magnetic particle-particle interaction, thin chain-like clusters are formed from an anchored particle trapped around a magnetic pole. Moreover, if the separation distance between the two poles is sufficiently near, an arch-type cluster is formed between the magnetic poles, and is located in a vicinity area nearer to the wall surface due to the influence of a flow field. For the case of a small aspect ratio r_p=3, in the situation that the particle volumetric fraction is constant, an arch-type cluster formed between the magnetic poles can remain trapped in the vicinity of the wall surface even under the influence of the strong flow field. Hence, we understand that the use of disk-like particles with a small aspect ratio may be able to improve the trapping performance of particles.

Al₂O₃－水ナノフルードの層流強制対流熱伝達特性を数値解析により検討した．直径の50 倍の長さを有する水平円管は入口から中央部まで断熱され，残りの部分は一定温度で冷却されている．円管に流入する高温のナノフルードは

Needle-free injection device using high-speed liquid microjets is expected to solve serious problems of conventional needles such as pain and blood infection. We investigate a control method of injection volume of high-speed microjet induced by a laser pulse illuminated into a point inside a liquid in a capillary tube. The volume control of a laser-induced bubble generated by laser focusing is important to control drug’s injection volume. In this paper, we aim to predict maximum bubble volume by modifying the previous bubble volume model. For validation of revised model, we compared calculations and experimental results which obtained from images taken by a high-speed camera. As a result, it turned out that the prediction of the revised model deviate from the experimental results. This result is important in that it indicates the necessity of reconsiderations about the model assumptions and fitting parameter estimation methods.

本研究では， X線CTスキャナから得られた間隙画像を対象に，円形要素充填法を用いて二次元場の間隙構造を分析した．また同画像に二相流格子ボルツマン法を適用し，水―LNAPLの二相流In-situシミュレーションを実施した．ダルシ―流速と動粘性係数の積を界面張力で無次元したパラメータであるキャピラリー（C_a）数が10^-4の流動条件では，流入口付近のLNAPLに作用する圧力は小さく，9 voxel未満の間隙までLNAPLが流入することがないことが分かった．またC_a数が10^-3の場合は流入口付近の圧力が増加し，C_a数が10^-4の場合には流入が確認できなかった9 voxel未満の間隙においても流入が確認できた．間隙の大きさによってLNAPLが流入できるC_a数が異なり，C_a数と間隙の大きさの関係が二相流動挙動において間隙中のLNAPLの残留及び浄化に影響を及ぼすことが明らかとなった．

The liposomes have been focused on as the packages of the molecular robots that change their shape by using the actuator molecules such as molecular motors, DNA, RNA, or any other added substance. To achieve the desired change in shape using the small force generated by these actuator molecules, it is crucial to understand the mechanical properties of the liposomes. For evaluating the mechanical properties of the liposomes, we applied a microfluidic device because microfluidic devices can trap and hold multiple liposomes quickly and simultaneously without skilled techniques. The microfluidic device consisted of multiple evaluation areas that connect in series. The evaluation areas were rectangular-shaped funnel channels designed to mimic the shape of the micropipette used in the micropipette aspiration method. The funnel width was approximately 5 μm. When the liposome suspension was introduced into the microchannel, each funnel trapped a single liposome. The membrane tensions of the liposomes were calculated from the deformation of the liposomes. The liposomes were prepared by the water-in-oil (W/O) emulsion method with a composition of POPC : DOPG : Cholesterol = 9 : 1 : 1. We confirmed that 20 funnels could trap liposomes, with a success rate was 45% (in one device). The average membrane tension of three liposomes was 0.40 ± 0.08 mN/m. By estimating the force of molecular actuators required for the formation of the tube structure using derived membrane tension, we demonstrated the effectiveness of the microchannel as a tool for developing molecular robots.

Al₂O₃－水ナノフルードの円管内層流強制対流熱伝達特性を非定常二次元数値解析により検討した．直径の50 倍の長さを有する水平円管は入口から中央部まで断熱され，残りの部分は一定温度で冷却されている．円管に流入する高温のAl₂O₃－水ナノフルードは

We present an analytical platform for visualization of cellular response to complex mechanical stimuli including fluid share stress and tensile stress. By calcium imaging with in vitro vascular model, we can measure intracellular calcium change under controlled mechanical stimuli. Moreover, the complex mechanical stimuli can be estimated by the theoretical calculation based on finite element simulation in order to compare with the measured calcium concentration.We cultured endothelial cells in a PDMS-based microfluidic device with perfusion. In addition, we calculated tensile stress distribution and flow velocity distribution in a microfluidic device with COMSOL simulation. We believe that the platform could be useful for understanding mechanotransduction.

Enhancement of the critical heat flux in pool boiling by the attachment of a micro HPP on a heated surface is investigated experimentally using water under saturated boiling conditions. HPP enhance the CHF from the capillary supply of liquid onto the heated surface through the pores and the release of vapor generated through the channels. When the height of the micro HPP on the heated surface is 1.4 mm, the CHF increases to 2.5 MW/m². While the CHF began to decrease when the thickness was more than1.4 mm. In regions of thin HPP thickness, the CHF can be explained by the Haramura-Katto model. Therefore, in this presentation we examined the CHF mechanism in the thicker HPP region using the capillary limit model.