Chemical mechanical polishing (CMP) is a very precise planarization technique where a wafer is polished by a pad. Slurry is dropped on the rotating pad surface and is supplied between the wafer and the pad. This research aims at reducing the slurry consumption and supplying fresh slurry evenly under the wafer. Grooves on pad are expected to supply slurry evenly and to remove wasted particles. Our objective is to develop the design of the best patterns of grooves using computational fluid dynamics (CFD). In this paper slurry flow is studied using the volume of fluid method (two-phase model for gas and liquid). Slurry flow simulations were carried for flat pad, for circularly grooved pad, for various flow rate and slurry supply position.

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An experimental study of counter-current annular two-phase flow of high-viscosity liquid and air in a large diameter pipe was carried out to investigate the inception criterion for entrainment of molten slag droplet in an entrained flow coal gasifier. Liquid film thickness was measured using a high-speed camera for 4 types of liquid with various viscosities and surface tensions. It was clearly shown that the measured average wave amplitude had a good correlation with the gas Reynolds number, and that the predicted critical gas velocity for droplet inception using new formula of wave amplitude had a good agreement with the experimental results under the condition of very low fluid Reynolds number (Re_f≤10). The critical Weber number Wec=1.73 was obtained as inception criterion of droplet entrainment.

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The MCF conductive rubber, combining the MCF in a silicon-oil rubber, has been developed by Shimada a few years ago. Recently, by means of the MCF electric conductive rubber, we are developing a haptic sensor for the applications to a robotic finger, artificial skin, and so on. For the purpose of the applications, it is important to understand dynamic characteristics of the MCF electric conductive rubber. In this paper, at first, we investigated the Young's modulus and the relation among the Young's modulus, electric resistance and temperature sensitivity. Secondly, we investigated the effects of the concentration of the particles in the MCF rubber and applying magnetic field on the MCF rubber on the dynamic characteristics.

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This paper describes the effect of shape parameters of perforated plates on the flow resistance of the perforated plate used as a vent plate or the cover in electronic equipments. In this study, we focused on the effect of hole shape and opening state of outer edge as the shape parameters of perforated plate. The study was focused on natural air cooled electronic equipments. In this study, in order to demonstrate the effect of hole shape as accessible value for design engineers, the design of experiment (DoE) method was used to design the experimental sample perforated plates. The effect of outer edge was evaluated by comparing the flow resistance of perforated plates with hole on outer edge and the perforated plates without hole on outer edge. In addition, to present the flow resistance data as thermal design information, the flow resistance data obtained in this study was arranged by empirical formula.

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This paper details experimental studies on the flow field around a linear cascade of low-pressure turbine airfoils whose solidity is changeable. Highly loaded low-pressure turbine (LPT) blades are one of the key paths to successful future aero-engines, however these blades are usually accompanied with separation bubble, eventually leading to the increase in aerodynamic performance. The purpose of this study is therefore to clarify any favorable effects of incoming wakes upon the aerodynamic loss of high-lift or ultra high-lift rotor blade cascade through the measurements of wake-affected boundary layers including separation bubble under low Reynolds number conditions. Cylindrical bars on the timing belts work as wake generator to emulate upstream stator wakes that impact the rotor blade. Hot-wire probe measurement is conducted over the blade suction surface to understand to what extent and how the incoming wakes affect the boundary layers containing separation bubble. Time-dependent transitional behaviors due to the wake passing are examined through the detailed inspection of several composite maps of flow properties displayed on time-space diagrams.

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This paper describes a detailed study of the flow structure over repeated two-dimensional flat plates on a ground plane for various values of S/D, and the optimum value of S/D to augment the turbulence intensity near the ground plane. The pitch between the two adjoining flat plates was varied at S/D=2, 4, 8, 12, and 16. The time-mean velocity and turbulence intensity were measured by Laser Doppler Velocimeter. As a result, it is concluded that (i) the flow structure over the repeated two-dimensional flat plate is divided into two types due to the reattachment of streamline left from the top edge of the flat plate on the groove between two plates, and (ii) S/D=8 is optimum to augment the turbulence intensity in the groove between flat plates, when the two-dimension flat plates are aligned on the wall as a turbulence promoter.

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As a part of the study on the jet diffusion, the jet flow issuing from a circular pipe with the fluttering fins made of the artificial cellulose has been investigated. In this paper, the turbulent characteristics of this flow field were examined from the velocity information obtained by the high-speed PIV method. The experiment was carried out without the fins and with the fins having various lengths. As a result, it has been found that the turbulence is enhanced in the jet flow due to the fin oscillation and a large scale fluctuation appears with the increase of the fin length. From the results of the auto-correlation it has been clarified that the turbulent structure contained in the jet flow was destroyed by attaching the fins near the outer edge of the jet flow. Furthermore, from the continuous wavelet transform analysis of the fluctuating velocities, it has been recognized that the jet flow tends to contain the lower frequency with the increase of the fin length.

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In the present study, in order to investigate unsteady effects on propulsion during front crawl swimming, unsteady fluid forces acting on a discoid airfoil simulating a human hand and the vortical flow field were measured in the (sinusoidal) pitching motion for the wind tunnel test, because the motion of a hand in swimming is obviously unsteady. The wind tunnel test has the advantage to enable many unsteady parameters to be changed easily. The pitching motion is available for keeping lift higher after the separation occurs. The delay of stall was observed and also a much larger lift force than the quasi-steady-state value was obtained in the pitching motion. In addition, the hysteresis in dynamic lift curve during the pitching motion decreased with increasing the pitching frequency. The unsteady effects of the pitching airfoil were affected by the stall characteristics of an airfoil under the stationary conditions.

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In the present paper the attention is focused on the relation between acoustic resonance and vortex shedding from tube banks in boiler plant. We have built a similar model of actual boiler plant to clarify the characteristic of acoustic resonant phenomena and vortex shedding. The model includes tube banks with in-line arrangement with a small tube pitch ratio. The relation between the acoustic resonance of actual plant and that of the similar model was examined. We measured the sound pressure level, the mode shape of acoustic pressures, the spectrum of velocity fluctuation and the gap velocity. As a result, the resonant frequencies and the mode shapes of acoustic resonances in actual boiler plant agreed well with those of the similar model. We found many peak frequencies in the spectrum of sound pressure level when the acoustic resonances occurred. The typical Strouhal numbers at onset velocity of acoustic resonances were about 0.19, 0.26 and 0.52. The periodic velocity fluctuation caused by the vortex shedding was remarkably observed inside of tube banks without acoustic resonance. The measured Strouhal number of vortex shedding became 0.15. The acoustic resonances of higher order modes were generated in this plant.

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In this study, characteristics of phase lag between displacement of forcibly oscillating test body and velocity fluctuation caused by vortex formation behind the test body were investigated. A right isosceles triangular cross-sectioned prism was used as the test body. The base of the isosceles triangle is 100 mm and span-wise length of the prism is 300 mm. The test body was rotationally oscillated at seven different frequencies from 0.205 Hz to 0.235 Hz in 0.005 Hz interval providing the natural vortex shedding frequency is 0.220 Hz. As the result, the behavior of the phase lag is summarized as followings. i) In general sense, it is well known that the phase lag is shifted by π within the lock-in region. Besides that, intermittent phase slip was observed. ii) The velocity fluctuation does not synchronize perfectly with the forced oscillation even when the frequency of the forced oscillation is set to natural vortex shedding frequency of the test body. iii) For the case of forced oscillation frequency is set to the natural vortex shedding frequency, synchronization rate of the velocity fluctuation with the oscillation was found to be at most 80%.

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The present paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow that is discharged from a convergent-divergent nozzle. The noise phenomenon of flow is generated by an emission of 'transonic tones'. The results of obtaining show that the frequency of a transonic tone that differs from the frequency of a screech tone due to the shock-cell structures in a jet, and originates in the shock wave in the nozzle increases in proportion to the nozzle pressure ratio. The transonic tone of high-order has the directivity in the direction of the flow. As for the frequency of the transonic tone, the separated zone was calculated by using a simple flow model by whom the propagate perturbation was considered. The calculation results by the model were corresponding to the present experimental results well.

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The objective of the study is to clarify the configuration of micro-layer formed between growing bubble and the heat transfer surface in nucleate pool boiling of region of isolated bubble. Micro-layer thickness was measured by specially devised measuring system applying the laser extinction method. The thin optic fiber of 94 μm in diameter arranged in a thin stainless tube was inserted in the liquid pool with the gas blowing both for preventing the getting wet of fiber made of fluorinated glass and removing the pool water in the path of laser light. The precision of the measurement was improved by using the two high speed cameras to decide the distance from bubble incipient site. It was elucidated that the thickness of the initially formed micro-layer was decided uniquely. The thickness was between 1 μm and 8 μm and was increased with the increase of distance between incipient bubble site and measuring position independently upon heat flux in this experiment.

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Sodium acetate trihydrate is considered as the promising thermal energy storage material due to its high melting enthalpy at the melting temperature of 58°C. However, incongruent melting (phase separation) and remarkable supercooling are made difficult to use. In this study, solidification process of the sodium acetate trihydrate from supercooled state was both experimentally and numerically investigated. On the experiment, effects of supercooling and sodium acetate concentration on the crystal growth rate were measured by varying the supercooling temperature (-48K) and the sodium acetate concentration (40-55wt%) and obtained an empirical equation. Further, simplified crystal growth model, which is based on the experimentally obtained crystal growth rate, was also proposed and the heat release process, which is important for the thermal energy storage equipments, was investigated.

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Direct numerical simulation was performed for a spatially advancing turbulent flow in a two-dimensional curved channel. Fully developed turbulence generated by straight channel simulation was used as the inlet value of curved part simulation. The radius ratio of the curved part, α, was set 0.92, the same as Kobayashi et al.'s experiment. However, the frictional Reynolds number, Re_τ0, was assigned 150, which was roughly quarter the experiment and allowed direct simulation of all the essential scale of turbulence. Computation was made for three cases changing domain size, and mainly discussed was the results from the computational volume extending 150° with spanwise length of 7.2 times channel half width. In this case, total number of 512×61×128 grid points was allocated. Numerically solved mean velocity showed trends consistent with the experiment in spite of the Reynolds number difference. Mean velocity normalized by the local frictional velocity indicated upward and downward offset of the logarithmic region, respectively, in the inner and outer side of the channel, but simulation showed stronger laminarization near the inner wall due to the low Reynolds number effect. Numerical data of mean velocity field illustrated that characteristic behavior of ejection from the outer wall and streamwise vortices appeared with advancement of large scale vortices. Power spectrum analysis implied that coherent structures near the outer wall were related to the birth and formation of large scale vortices.

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High density culture is one of the essential technologies for an engineered tissue where cellular physiological functions such as enzymatic reactions are required. Cellular energy metabolism and adherence to scaffold are the most important factor to design high density culture. In this study, we developed flow chamber with which steady state measurement of glucose and oxygen metabolic rate of HepG2 cell line can be measured. In addition, cell adhesion ratio was measured using the same flow chamber. The results provided not only glucose and oxygen consumption rates to glucose concentration, but also the interaction of both consumption rates on glucose concentration. Cell adhesion ratio under various shear stresses showed that HepG2 cells are detached under the shear stress around 10-60 Pa. This large diversity of detached shear stress suggests that the adhesion force of collagen fibers to substrate may dominate the detachment.

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In order to clarify the effects of vortex core radius on the vortex bursting phenomenon, the premixed flame propagation in swirling flow has been examined by the numerical calculation for various vortex core radii. In this calculation, the flame is fixed in the computational domain by adding an axial flow to the unburnt premixed gas so as to obtain the steady state propagation characteristics. The obtained results are as follows : The obtained relationships between the maximum circumferential velocity and the flame propagation speed or the flame region radius agree with the previous studies. Moreover, the effect of vortex core radius on the flame propagation speed and flame shape are clarified. When the vortex core radius is less than 7 mm, the flame propagation speed is dependent on both the angular speed and the vortex core radius. On the other hand, when the vortex core radius is more than 7 mm, the flame propagation speed is directly proportionate to the angular speed not but the maximum circumferential speed, and it is not dependent on the vortex core radius.

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The flame structure of unsteady two-dimensional counterflow premixed flame is investigated by numerical simulation with elementary reaction mechanism. In order to investigate unsteady behavior sinusoidal fluctuations are added to the inlet velocity as follows : u₀=u_m {1+A·cos (2πky) ·sin (2πft)}. We consider two types of counterflow ; one is methane-air premixed mixture/air counterflow, and the other is methane-air premixed mixture/burnt gas counterflow. The flame structure and the unsteady behavior in each type of counterflow are investigated under the condition of very high intensity of fluctuation (the average velocity : u_m=1.0 m/s, the amplitude : A=5). It is shown that the local quenching, the unburned island and the burnt island are generated. These phenomena are examined by the distributions of chemical species and heat release rate near flame surface. Moreover, it is shown that the turbulent burning velocity, which is evaluated based on 0₂ mass consumption rate, is directly proportionate to the flame surface area, and the time variation of the spatial averaging burning velocity per unit flame surface area is small compared with that of the flame surface area.

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Experimental studies are conducted on extinction of non-premixed dimethyl ether (DME) flames stabilized in the counterflow configuration. Studies are carried out by injecting a fuel stream made up of fuel and inert gas (N₂ or CO₂ or Ar or He) from one duct an oxidizer stream made up of O₂ and inert gas (N₂ or CO₂ or Ar or He) from the other duct. Critical conditions of extinction are measured by increasing the flow rate of the counterflowing streams until the flame extinguishes. Numerical studies are also performed using detailed chemistry at conditions corresponding to those used in the experiments and compared with measurements. The present study highlights the examination of the influence of equilibrium flame temperature, flame structure and kind of inert gas on extinction properties of DME. Results are compared and discussed in terms of Lewis number effect.

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A theoretical study has been made on the transport phenomena of the blood flow in the human body. To develop a discussion about the enthalpy transport in the bio-heat equation, we will need the information about a velocity field of blood flow. Therefore, we have proposed a bio-heat equation along with bio-continuity and momentum equations. With the aid of a local volume averaging, the macroscopic governing equations are derived from the microscopic governing equations, where the flow in the arterial and venous blood vessels is treated as one-dimensional pipe flow and the flow in the capillary blood vessels is approximated as the flow through porous media. Furthermore, we examine the boundary condition at the interface between the fluid and porous layers, and clarify the mechanism of the interfacial heat transfer between the artery (or vein) and the tissue.

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