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In the previous paper, the author reported the theory of the Chain Construction with Elastic Joints as well as the results of the experimental study on the Sandwich Curtain Wall. It was shown that the theory could be applied to the wall with c10se approximation in its vertical direction. In the horizontal direction however it was found isotropic. The present paper deals with an experimental study on deflection of the Rectangular Plate composed of isotropic plates and elastic joints. The test plate was constructed with plywood-panels and rubber-strings.

application/pdf, This paper is a part of the experimental investigations on the characteristics of the Flow around flat plates vertically immersed in turbulent boundary layers. In the first and second papers，were the characteristics of the flow around a flat plate i.e. the distributions of velocity and pressure， the flow patterns and interference effects of the tunnel walls on the form drag， discussed. In the present paper， correlations are obtained for the variation of the form drag of double flat plates with the distance of the flat plates and the characteristics of the boundary layer in which it is vertically mounted.

This paper describes the internal structure of curved flows based on measurements of threedimensional velocity components in the curved reaches of smooth rectangular channels underconditions of subcritical flows.Considering the properties of three voriticity components observed, the flow through acurved section was divided into three regions: the generated region, the developed region andthe fully developed region of secondary flow. The magnitude of secondary flow predicted fromthe longitudinal vorticity equation was confirmed by the experimental results in the generatedregion. Further, the radial distribution of tangential velocity measured in the fully developedregion supported the theory of pervious papers.

In this paper, nonlinear free vibrations of clamped rectangular plates with immovable edges are shown by using Karman's equations composed of the terms of the stress function and the deflection of the plate. The solution of this problem is obtained by the application of Galerkin's method in which the normal function of vibration is assumed by the product of the normal mode of clamped-clamped beam with arbitary axial force which is determined so as to give more reliable solution. Numerical results are illustrated for the square plate. At first, small amplitude vibrations of the clamped plate are treated as the special case and the accuracy of the proposed method in this paper is checked. Finally nonlinear vibrations of the clamped plate are analyzed and compared with previous solutions.

Introduction. In the previous paper I have investigated the variation of lift and drag on a model wing in a wind tunnel. The first part of the paper dealt with the case of a flat plate between parallel walls. Recently Rosenhead re-investigated this case and obtained a different result. In the second part of my paper I have dealt with the case of a flat plate in an unbounded jet of air. For this case von Karman has obtained an approximate formula which is in close agreement with mine. It was considered that the case in which the model is put in an unbouned jet of air does not represent the case of a wind tunnel of Gottingen and Eiffel type, and the mouthes of the tunnel must have some effect. For the effect of the exit wall L. Poggi has derived a formula, which shows this effect is very small. Ono also has calculated this effect independently. In the present paper I have treated the problem in a different way, and in the third part of the paper I have investigated the effect of both the exit and the collector walls of the wind tunnel. I. The effect of an exit wall. The form of the flow in this case is shown in Fig.1. The air flows from infinity with the velocity -U between parallel walls till the exit, out of which the air flows as a free jet and impinging upon the model the direction of it is deflected. It is theoretically possible to treat this kind of flow as a two dimensional problem in hydrodynamics, but as it is mathematically very complicated we treat the case shown in Fig.2, which represents infinite number of parallel walls and models. It is enough to consider the region ABPP'B'A', if we obtain some functions with the period id. If we consider the region between two stream lines along AB and A'B' the form of flow resembles very much to that of Fig.1, and so the lift and drag on the model calculated in both cases will be nearly equal. This was proved formerly in my paper in the case where the walls are absent. The analysis is made and the result is shown in the expression (6). II. The case in which the model is replaced by a point vortex. The case resembles to the case treated by Poggi, and the result is the same as that obtained by him. The result is shown in the expression (7). III. The effect of both the exit and the collector walls. The form of flow is shown in Fig.12, and the result is shown in the expression (8). It is shown from the results of investigation made in this paper, the effects of both the exit and the collector walls are very small, and so we can consider as though both the mouthes are absent and the model is put in a free jet in treating the lift and drag on a wing model in a wind tunnel of Gottingen and Eiffel type., 資料番号: SA4146516000

In this paper, nonlinear free vibrations of clamped rectangular plates with immovable edges are shown by using Karman's equations composed of the terms of the stress function and the deflection of the plate. The solution of this problem is obtained by the application of Galerkin's method in which the normal function of vibration is assumed by the product of the normal mode of clamped-clamped beam with arbitary axial force which is determined so as to give more reliable solution. Numerical results are illustrated for the square plate. At first, small amplitude vibrations of the clamped plate are treated as the special case and the accuracy of the proposed method in this paper is checked. Finally nonlinear vibrations of the clamped plate are analyzed and compared with previous solutions., 長崎大学工学部研究報告, (3), pp.55-64; 1972

As described in a previous paper', the flow through a simple curved open channel maybe divided into three regions a generated region, a developing region and a fully developedregion of secondary flow.In the first part of the present paper, the existence and the properties of these regions arereexamined by a series of experiments shown in Table- 1 . From the longitudinal distributionsof three mean vorticity components observed, it was found that the flow in the curved reach hasthe characteristics of the generated region and the developing region, and the fully developedregion will be never reached in many practical cases.In the second part, the vertical distributions of radial velocity with or without the effects ofbed wall friction are discussed. Considering small perturbations from a flow as a free vortex, thedistributions of radial velocity are derived from longitudinal vorticity equations for a laminar anda turbulent flow. The experimental results within the generated region support the theoreticalconsiderations.

In the previous paper,the erosion damages have been discussed by using on two parallel surfaces oscillating at close proximity in liquid. In the present paper,further erosion tests are carried out on the curved surfaces which are frequent1y found in machine elements. In this test conditions,the shearing force of squeezed film becomes very small,and the damages are mainly caused by the collapse pressure of cavitation bubbles. The cavitation bubble moves due to the flow of liquid film in the radial direction and no fixed-type cavitation appears at the small film thickness. Accordingly,t he distribution of damage in the radial direction of the spherical disc depends on the minimum fi1m thickness and also on the curvature of disc.

application/pdf, This paper is a part of experimental investigations on the characteristics of the flow about flat plates vertically immersed in turbulent boundary layers. In the first paper，the characteristics of the flow about a flat plate i.e. the distributions of velocity，pressure and the now patterns， were discussed. The present paper describes both theoretically and experimentally the interference effects of the tunnel walls on the behavior of the streamline separated from the edge of the plate， together with the variation of the form drag of the plate.

Linear stability of a pipe conveying fluid has been studied as a classical problem of the elastic stability problem. The straight position of a pipe can be destabilized by Hopf bifurcation. The critical value of the fluid velocity at which the straight position of a pipe loses its stability is called critical flow velocity. When the fluid velocity is slightly smaller than its critical value for the Hopf bifurcation, the damping ratio of a certain mode becomes very small. In such region, the forced vibration of a pipe comes up as a problem, when subjected to the external excitation. In this paper, we theoretically investigate the frequency response of forced vibration of a pipe which is subjected to the external excitation.

In this paper, modeling for the simulation of the avalanche by a particle method is discussed. There are two kinds of the snow avalanches, one is the surface avalanche which shows a smoke-like flow, and another is the total-layer avalanche which shows a flow like Bingham fluid. In the simulation of the surface avalanche, the particle method in consideration of a rotation resistance model is used. The particle method by Bingham fluid is used in the simulation of the total-layer avalanche. At this time, the plastic viscosity of Bingham fluid is shown from the creep factor and the Glide coefficient of the snow which can be found from an experiment.

Aerodynamic drag accounts for a large portion of the total resistive force when the solar car is running in the race. It is a significant power loss at any speed above 40 km/h. In this paper, an approximate simulation model is presented on MATLAB Simulink. We tried to calculate aerodynamic drag and average speed by using measured value of Solar Car on the simulation model.

This paper presents a method for damping sloshing in a liquid container during its transfer by a cart that is equipped with an active vibration reducer with six-degree-of-freedom parallel linkage. Sloshing is generated during the liquid container transfer. To damp this sloshing, it is tilted and horizontally moved by the active vibration reducer. The reducer is controlled by a linear quadratic regulator. A weighting matrix of the quadratic performance index is optimized using a genetic algorithm. Gain scheduling is used to apply it to any liquid level of the container. The cart is driven along a straight path on a horizontal plane. The usefulness of the control system is verified through a simulation and experiment.

Many kinds of ducts are employed in many places for such purposes as water supply and drainage, inhalation and exhaust of gases, electromagnetic wave guides, and transmitting sound. In this paper the dependence of sound propagation in a finite unflanged circular duct and sound radiation from the open end of a duct on duct length and sound frequency is discussed. The sound pressure at the central duct axis, amplitude and phase of the sound pressure at the open end, and the radiated sound pressure directivity were measured. From these values, the end correction, radiation impedance at the open end, and attenuation value were obtained and compared with similar values in other references. The experimental results were explained from the general theory of sound. As shown in table 1 the experimental values are much the same as in other papers and, in cases with different characteristics, they are similar.

Spark ignition (S.I.) engines are widely used for cars, motorcycles, generators, and so on. However, S.I. engine emits carbon dioxide, which becomes the origin of global warming. Therefore, it is necessary to improve the thermal efficiency of S.I. engine for reducing the emission of the carbon dioxide. A gas flow is often generated in the cylinder of the engine in order to promote combustion for improving the thermal efficiency. While the gas flow increases the thermal loss, as the heat transfer on combustion chamber is promoted. So it is necessary to be obtained relation between the flow velocity and the heat transfer coefficient. Nevertheless, it is difficult to measure the velocity of the in-cylinder burnt gas flow. Whereas, it is thought that the heat transfer coefficient is related to the time after ignition. This paper reports that the heat transfer coefficient on the combustion chamber walls is obtained as a function of time by using of the relation between Nusselt number and Fourier number.

application/pdf, e paper presents a finite element method for the analysis of shape optimization problems of a body in a flow of viscous incompressible fluid. It uses the actitious domain approach extending the çuid domain into the domain occupied by the body. In the fictitious domain method, the body surface is not treated as a part of boundaries of a computational region, and the accuracy of the gradient of an objective function on the body surface decreases. Therefore, it is hard to use the optimization technique that needs diãerential operations on the body surafce with the fictitious domain method. Then, in the present study, we adopt the downhill simplex method which requires only function evaluation, not derivatives. The proposed method is applied to the calculation for obtaining the minimum drag shape of an axisymmetric body in a steady Stokes fiow, and to the optimization of the nose shape of a high-speed train.Encouraging numerical results have been obtained.

Characteristics of the most unstable wave of baroclinic instability are often interpreted as resonance of two Rossby waves in the upper and lower layer. In this paper, we considered this interpretation in more detail to deepen our understanding of baroclinic instability.

This paper discusses a mechanism of nonlinear interactions between tow nonlinear coupled Rayleigh's equations. Rayleigh's equation is well-known as a mathematical model to investigate the self-excited vibration. We present a nonlinear analysis based on the multiple scale method to solve this problems. Using the multiple scale method, we obtain two nonlinear evolutional equations of the amplitudes. The results obtained from this analysis are useful to advance the study of mixed modal self excited and double flutter problem.

Air bubbles in hydraulic oil lower the efficiency of hydraulic systems and contribute to instrument malfunctions. In order to improve these problems, it is useful to use an active bubble elimination device termed a bubble eliminator, which removes air bubbles using a swirl flow. The purpose of this study is to optimize the shape parameters of the device. In this paper, experimental flow visualization and numerical simulations of flow in the device were conducted to investigate the effect of the shape parameters of the device on the behavior of the bubbles in the oil, and shape parameters were optimized using spiral number as a new index.

This paper presents visualization of boiling phenomena and formation of the two-phase flow pattern in a mini tube which has a 0.30mm inner diameter. Test fluid is refrigerant HCFC123. ITO film is formed by vapor deposition over the outer surface of the glass tube. This film is transparent and electrically conductive. Refrigerant HCFC 123 is pumped into the glass tube in liquid phase; it then is boiled away by electrical heating. Bubble formation and growth near the onset point of nucleate boiling and the two-phase flow pattern in the low-quality region is recorded via high-speed video camera (10,000 — 50,000 fps). Appearance of bubble formation and growth in a mini-tube depends on heat flux and mass flux. For low heat flux, an isolated bubble grows to occupy the whole tube cross section, and flows in a form resembling a bullet. Liquid film is not observed between this vapor bubble and the inner tube surface, and evaporation is not so dominant. For high heat flux and low mass flux, bubbles grow to coalesce immediately into a long vapor plug; and both nucleate boiling and evaporation from liquid film between the vapor plug and the inner tube surface remain dominant.

The heat transfer and fluid flow characteristics of a viscoelastic fluid flow in a serpentine channel are described in this paper. The average heat transfer coefficient, pressure loss, and flow visualization were measured under the Reynolds number conditions of Re = 0.5~2.0. Water solutions of polyacrylamide with sucrose and plain sucrose were employed as viscoelastic fluids and Newtonian fluids, respectively. An increase in the Nusselt number with increasing Reynolds number in the case of the viscoelastic fluid flow was observed in the serpentine channel, while in the case of the Newtonian fluid flow, the Nusselt number remained approximately constant. The visualization results revealed that unsteady flows with a large fluctuation and longitudinal vortex-like secondary flows were generated in the case of the viscoelastic fluid flow, particularly downstream of the inflection point of the serpentine channel. This was believed to be attributed to the increase in the flow instability and the normal stresses produced by the elastic property of the fluids. Further, the Nusselt number increased even in the case of the viscoelastic fluid flow in the straight channel, relative to that in the case of the Newtonian fluid flow. However, this increase moderate in comparison to that in case of the serpentine channel, which indicates that the heat transfer enhancement can be obtained effectively by a combination of the viscoelastic fluid flow and channel geometry. A considerable increase in the pressure loss penalty was observed in the case of the viscoelastic fluid flow. However, the viscoelastic fluid case showed a higher overall performance in terms of the pumping power.

本論文ではパーティクル法とウェーブレット解析を用いた高速な乱流シミュレーション手法を提案する．高速に流体の流れを再現するためにパーティクル法の一種であるSPHを用い，そのパーティクル間の相互関係から直接ウェーブレット解析により乱流が発生する領域を検出する方法を提案する．検出された領域にウェーブレットノイズに基づき渦場を付加することで乱流を再現する．さらに，乱流エネルギーに基づきパーティクルを分割・回転させることで，サブパーティクルスケールでの乱流を実現する．最後にこれらの処理のほとんどはGPU上で容易に実装可能であり，リアルタイムに近い速度で実行できることを示す．This paper presents a fast simulation method for turbulent flow which uses a particle method and wavelet analysis. To simulate fluid flow, the method uses smoothed particle hydrodynamics (SPH), which discretizes the fluid into a collection of particles, and detects regions where turbulent flow will occur by using wavelet analysis without a spatial grid. By taking the curl of wavelet noise, the turbulent flow is then appended as a divergence-free turbulence velocity field. Additionally, by using a particle splitting, which characterize the vortex features of turbulence, a sub-particle-scale representation of turbulent flow is proposed. Implementing almost all processes on a graphics processing unit (GPU), simulations are performed in near real time.

In this paper，we discuss the linearity and the nonlinearity of a sequence space Ap(ƒ) induced by a Lp-function ƒ. In particular，we give examples of Lp-functions such that Ap(ƒ) are not linear.

In order to simulate unsteady three-dimensional airflow around urban city area with characteristic length scales of the order of kilometers, we have been examining the large-eddy simulation (LES) technique using a finite-difference method (FDM). In this paper, using the LES technique, we have performed the calculation of buoyant gas diffusion around real urban area with huge computational grids. The various patterns of gas diffusion are clarified, and airflow is also locally accelerated or decelerated, due to the topographic and the obstacle effects.

[Abstract] This paper presents an experimental investigation on forced convective boiling of refrigerant HCFC123 in a mini-tube, and visualization of boiling phenomena at the onset points of nucleate boiling is conducted. It was indicated in the former report that heat transfer characteristics of forced convective boiling in mini-tubes, of which inner diameter is φ0.51mm and φ0.30mm, were different from those in conventional tubes. In order to clarify this difference of heat transfer characteristics, bubble formation and departure at the onset points of nucleate boiling were observed and investigated, using a glass tube on which ITO film is formed. The bubble diameter at departure becomes small with mass flux and becomes large with heat flux in a mini-tube. The bubble occupies almost the whole tube cross section and grows up into a long thin vapor plug as heat flux becomes larger. Accordingly, forced convective evaporation can be dominant for low mass flux and high heat flux, and this is so different from heat transfer characteristics in conventional tubes. From these results, there seems to be some potential that nucleate boiling around the onset points influences formation of flow pattern in mini-tubes.

[Synopsis] The example of matter in the Bose-Einstein condensation is liquid He II . The liquid Hell has many strange properties different from normal liquid. In this paper, we translate a part of "CHAPRER 13 SUPERFLUIDS in STATISTICAL MECHANICS SECOND EDITION written by KERSON HUANG" into Japanese and properly explain the difficult parts of it. The liquid He II is a superfluid and it is a fluid that flows without dissipation of energy. The liquid Hell can flow through the tiniest tube (0.1μm ＞＞ diamete) without viscosity. The liquid He II craw up walls and coat all inside surfaces of its container. And if it is placed in a open beaker, the liquid will craw up the wall, across the rim, and out of the beaker. Tisza's two-fluid model is made up of two components called the normal fluid an the superfluid. The normal fluid is supposed to behave like an ordinary classical fluid, whereas the superfluid has the unusual properties that its entropy is zero. In this way, we can understand many strange properties (mechanocaloric effect, fountain effect, and second sound phenomenon) of liquid He II .

This present paper is intended to show some experiments and discussion about autonomously motion of droplet on hydrophilic/hydrophobic-patterned substrate. An array of triangular PTFE works as specific pattern to have gradient wettability on a glass substrate. Water micro droplet can autonomously moved from hydrophobic region to hydrophilic region along the pattern. Both of pattern geometry and droplet size become the difference between success and failure of the droplet motion. Contact line geometries of water droplet allow us to estimate driving force and necessary condition for autonomously droplet motion. The obtained value is well consistent with the experimental results. The authors also apply multi-step motion by sandwiching in droplet between two patterned substrates. Another substrate changes in direction of droplet after initial motion on a substrate. The droplet position can be controlled with mm-scale resolution.

[Abstract] In this paper, it is a purpose to obtain basic information of a hydrogen jet and combustion flame characteristics of the hydrogen rotary engine. The jet characteristics of the hydrogen gas injector were measured by using the high-speed shadowgraph method. As the result, the jet penetration of the low density gas was weak. The mixing of the direction of the jet axis was disturbed for the low jet pressure. Next, the combustion flame propagation of the hydrogen rotary engine was visualized by high-speed camera system with a transparent engine. The flame propagation was fast in the hydrogen combustion. It became clear that the end gas burn quickly at upstream combustion chamber.

[synopsis]In this paper, it aimed to clarify the behavior and the flow field of a supersonic jet flow issuing from a divergent nozzle widely used in industry. Especially, the separation point of the flow was controlled by vertical control jets to the separated supersonic jet flow at the divergent part of the nozzle. By such a method, the boundary layer control of the supersonic jet flow issuing from the divergent nozzle was clarified. In this time, the flow field of the main jet flow has been clarified when the control jets were issued for the main jet flow with various stagnation pressures. Experiments and numerical analyses were completed when the stagnation pressure ratios of the main jet flow were given as Po/Pa ＝ 1.0, 3.0, 6.0 and the stagnation pressure ratio of the control jets were given as Pc/Pa ＝ 3.0. The control jets were vertically issued from eight small holes for the main jet flow. Moreover, numerical analyses were also made when the stagnation pressure ratios of the main jet flow were given as Po/Pa ＝ 10.0 and 20.0. In the experiment, the total pressures were measured around the exit of the divergent nozzle and the equi-total pressure distributions were examined. In the numerical analysis, the velocity contours of the flow were examined for the inside of the divergent nozzle and the downstream region of the flow. As a result, the main jet flow issuing from the divergent nozzle didn't be a round jet by a remarkable influence from the control jets. Moreover, it was found that the shape of the main jet flow was influenced considerably by difference of the stagnation pressure ratio.

In a core wall system high-rise building, the center core of which consists of four L-shaped core walls, under the action of a diagonal seismic force, the axial load of the core wall is very high. Particularly the corner and the area near the corner of the L-shaped core wall are subject to high compressive stress. Reinforcing these areas is therefore considered effective in improving the deformation capacity of the core walls. In this paper, lateral loading tests were conducted on wall columns which simulated the corner and the area near the corner of the L-shaped core wall.

The Fluid Flow in Rock Fractures during Shearing Processes Was Investigated in This Paper Considering the Evolutions of Aperture (Void Geom.) with Shear Displacement Histories under Constant Norm. Stress. the Distr. of Fracture Aperture and Its Evol. during Shear Were Calculated from the Initial Aperture and Shear Dilations Measured in the Lab. Coupled Shear-flow Tests. for the Fluid Flow Simulations, Three-dimensional Navier-Stokes (NS) and Two-dimensional Reynolds (Loc. Cubic Law) Were Solved Numerically and Simulat. Results Were Compared., 材料, 59(3), pp.205-210; 2010

In recent years, hydraulic energy as clean natural energy has attracted a lot of attention. In this paper, we proposed jet-type cross-flow water turbine for micro hydraulic generation. The characteristics of the jet-type cross-flow water turbine were examined and the experiments on the visualization of flow were conducted by using transparent model water turbine. The following were clarified in this study. The jet-type cross-flow water turbine makes it possible to generate electricity in the low head. Internal flow of jet-type cross-flow water turbine is classified into two types: reactiontype and impulse-type. The flow becomes reaction-type when rotational speed of water turbine is slow and impulse-type when it is fast. Inclining the direction of the jet flow makes wider the range of the rotational speed in reaction-type flow.

This paper presents the recent efforts to characterize the maximum load experienced by a Disk-Gap-Band type parachute to support Mars landing mission currently considered at JAXA. We simulated the structure-flow interaction with CFD solver coupled with a mass-spring-damper structural model. The interaction was modeled using a 3D elastic canopy model and the immersed boundary method. Flow parameters were computed for a Mach 1.6 free stream condition. The flow field solution was post processed to yield the drag coefficient. In addition, experimental campaigns were conducted at JAXA supersonic wind tunnel facilities. The time histories of the drag coefficient were recorded; the shock shapes and the canopy opening process were visualized by Schlieren diagnostics to provide data and validate the numerical models. The computed averaged drag coefficient was found to be within 5% with the measurement. The breathing frequency computed from Fast Fourier Transform analysis was found to be a similar tendency with the experimental data., 形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: DS1740292004

This paper describes about identification of damping coefficient of stir fin in liquid of vibrating mixer. We developed mixer of vibration type by using magnetically levitated fin. In device, mixing fin is levitated with the magnetic repulsive force in the mixer tank and excited from the outside by the magnetic field. The motion of the magnetically levitated fin has a very strong nonlinearity shows complex behavior. The damping coefficient is an important parameter to specify the motion of the magnetically levitated fin. In general, it is very difficult to estimate the damping coefficient of oscillator when damping is large. In this study, damping coefficient of stir fin of vibrating fin in water is identified by using phase method. The damping coefficient can be obtained by the experiment, and it was confirmed that damping coefficient is changed greatly depending on frequency.

The flow near the shoreline is deeply related to the growth and survival of living things of a tidal flat. Therefore, prediction of the coastal flow due to tides is important. In this paper, the cross-shore current due to the tides is studied combining the continuity equation for one dimensional flow and the water level change. The equations for line flux and the depth averaged velocity were btained by integrating the continuity equation from the instantaneous shoreline to the arbitrary position beyond the shoreline. Samples of calculation indicate that the stagnation of the flow occurs in front of the vertical structure constructed on the tide flat.

[Abstract] It is known that small quantities of surfactant additives can greatly reduce the friction factors during the flow of a heat transfer medium. This is because the generation of turbulent vortices is suppressed by the formation of rod-like micelles, and the flow remains laminar in the high Reynolds number range. However, the values of the heat transfer coefficients decrease during flow laminarization; this would result in a requirement for heat exchangers witha larger heat transfer area. The research objective is to examine heat transfer enhancement effects by air injection. This paper presents an experimental investigation on the heat transfer and flow characteristics in an air-surfactant solution two-phase flow through a vertical tube. Heat transfer coefficients were enhanced drastically with the injection of air into a drag-reducing surfactant solution flow. The enhancement rates were much larger for the surfactant solution than for water. However, heat transfer coefficients were smaller for an air-surfactant solution flowthan for an air-water flow due to the drag-reducing effects. As the gas quality increased, the heat transfer coefficients for air-surfactant solution flow approached those for air-water flow.

The uplift of the flat-bottom cylindrical shell tank has been considered to contribute to the various damage of the tanks. The motion of the free surface and the fluid pressure characterize dynamical effects of the fluid on the tank induced by the uplift motion. Therefore, to properly evaluate the seismic-resistance performance of the tank, account must be made of these behaviors mathematically and numerically. The present paper examines the applicability of the explicit FE-Analysis to numerically compute these behaviors. As we shortly see, the explicit FE-Analysis accurately predicts the motion of the free surface observed during the free rocking test of the tank and the fluid pressure on the tank mathematically derived based on Laplace equation and associate boundary conditions.

The purpose of this study is to make clear the effect of the spin-up acceleration on the boundary layer over the rotating wafer surface. In this paper, onset and breakdown of transient vortices are investigated because transient vortices interfere with the formation of uniform thin film. The air flow fields on the wafer surface are measured by a hot wire anemometer. The onset of transient vortices over the rotating wafer is detected by the spectra of the tangential fluctuating velocity. It is found that transient vortices appear at higher Reynolds number in the case of higher spin-up acceleration of the wafer. On the other hand, transient vortices break down at a certain Reynolds number and the transition of the boundary layer to the turbulent state is independent of the spin up acceleration.

In this paper, aerodynamic characteristics of the cross flow type of wind turbine were studied experimentally by using sub-scale model, considering the effect of guide vanes and its arrangement. The aerodynamics characteristics of the turbine for wind flow direction were discussed by reference to the power and the torque coefficients correlation of tip speed ratio for various combinations of approaching optimized guide vanes number and optimal configuration.

In a core wall system high-rise building, the center core of which consists of four L-shaped core walls, under the action of a diagonal seismic force, the axial load of the core wall is very high. Particularly the corner and the area near the corner of the L-shaped core wall are subject to high compressive stress. Reinforcing these areas is therefore considered effective in improving the deformation capacity of the core walls. In this paper, Eccentric compression tests were conducted on rectangular sections of columns which simulated the corner and the area near the corner of the L-shaped core wall.

In high-rise buildings with the core wall system, the axial load of the core wall is very high under the action of a diagonal seismic force. Particularly the area near the corner of the core wall is subject to high compressive stress. Reinforcing these areas is therefore considered effective in improving the deformation capacity of the core walls. In this paper, the lateral loading tests of core walls were analyzed using three-dimensional nonlinear finite element method. As a result of analysis, the influence of confinement effect of concrete at the area near the corner of the core walls to the deformation capacity was shown.

In this paper, a multi-objective design exploration for a three-element airfoil which consists of a slat, main wing, and flap was carried out by paying attention to the span wise flow effect. Reynolds Averaged Navier-Stokes Solver (RANS) was used for the evaluation during the design process. To reduce computational time, '2.5-dimensional span wise calculation' was used. In this calculation, two same planes were arranged along span wise direction. They were diagonally arranged to represent the sweep angle and periodic boundary condition was used for the infinite span wise calculation. Kriging based Multi-Objective Genetic Algorithm (MOGA) and ANalysis Of VAriance (ANOVA) were used for the design exploration. The objective functions were defined as the maximization of lift coefficient at landing and near stall conditions simultaneously. In this study, 54 sample points were evaluated for the construction of the Kriging model. Based on present evaluation method, the span wise flow was observed and it has an influence on the separation on the flap. Through the design exploration process, the differences of the designed results between 2.5D and 2D evaluation were observed by visualizing the design space., 資料番号: AA0063742012, レポート番号: JAXA-SP-07-016

In this paper, a study on sound propagation of H-2A rocket plume duct with deflector is analyzed using a hybrid code of an Euler flow solver and a Linearized Euler Equations solver. Several cases of calculation for modeled jet configurations of H-2A main engine, 202, and 204 rockets have been conducted. The results of these calculations indicate that sound waves from the modeled duct have different characteristic frequency according to jet configuration., 資料番号: AA0063742034, レポート番号: JAXA-SP-07-016

This paper presents a numerical study on ligament breakup mechanism due to capillary force. In contrast to the classical Rayleigh analysis, the effect of ligament tip is included to examine the role of capillary waves from the tip. The numerical setup corresponds to a series of microgravity experiments conducted at Nagoya University. Based on Weber's similarity law (We is approximately O(1)), a low-speed jet of liquid SF6 is injected into high-pressure (9.1 MPa) ambient nitrogen and short-wave breakup that is different from Rayleigh's analysis is observed in the experiment. The present numerical simulation has reproduced the same pinch-off and shown that droplet pinch-off from the tip is a combination of multiple phenomena. One is the short-wave breakup. Capillary waves from the tip propagate upstream, become unstable and lead to droplet formation at the tip. This is a closed and self-sustained cycle. This destabilization process is driven by the dynamics of the tip bulb and capillary waves. The elongation by the gas flow also strengthens the pinch-off. As the liquid column length becomes longer, the other mode of long-wave instability also appears. This mode corresponds to the convective Rayleigh mode. Short capillary waves from the tip reach the nozzle exit and are reflected. They become the source of this convective instability. The present study has shown that the ligament tip plays an important role in droplet breakup., 資料番号: AA0063742026, レポート番号: JAXA-SP-07-016

This paper provides the results of a numerical analysis on the sound transmission to modeled solid and hollow walls in order to investigate an acoustic characteristic of a honeycomb sandwich structure. The Finite Difference Time Domain (FDTD) method is used in this study because it is possible to solve both sound wave propagation in fluid and elastic wave propagation in solid simultaneously. From the results of isotropic solid wall calculations, there is the second transmission wave in the case of thick wall model, which is not observed in the case of thin wall model. On the other hand, the arch-shaped transmission wave is observed in the case of hollow wall model calculation, which is totally different from that of simple solid wall models., 資料番号: AA0063742019, レポート番号: JAXA-SP-07-016

In［2], we studied interpolation formulas for ten nodes, using the Taylor expansion. But, the errors at the top and the bottom of the nodes are bigger than the errors at the center. Therefore, at the top and the bottom of nodes, it is preferable to use the twelve-node interpolation formula or the fourteen-node interpolation formula. The purpose of this paper is to produce the twelve-node interpolation formulas using Taylor expansion for obtaining accurate values at the top and the bottom of nodes.

When we solve the initial value problem of ordinary differential equations, if we attempt to cut the step size in half using the ten-node central value interpolation formula, we find that it is not possible to cut the five nodes at the top and the bottom in half. The purpose of this paper is to produce formulas for the five nodes at the top and the bottom using Taylor expansions. The errors at the top and the bottom are bigger than the errors at the center. therefore, at the top and the bottom it is preferable to use the twelve-node interpolation formula, presented in ［2］.

On designing and developing products, the finite element analysis of three dimensional eddy current-thermal problems is very useful. This paper shows effectiveness of a large scale eddy current-thermal analysis for a transformer tank using the domain decomposition method.

In this paper, experimental results were reported to investigate a behavior of combustion wave when a shock wave was transmitted into a combustible premixed gas of oxygen and hydrogen. In general, phenomena occurring in the premixed gas would be classified into four types, i.e. (a) the shock wave was just transmitted without causing ignition for the shock wave propagated with low-Mach number, (b) the gas was ignited behind the shock wave and a deflagration wave was propagated following the shock wave, (c) the deflagration wave was transited to a detonation wave behind the shock wave, (d) a detonation wave was directly initiated just behind incident shock wave having high-propagation Mach number. In this study, a shock wave produced by a detonation-driven shock tube was transmitted into a premixed gas of oxygen and hydrogen varied with an equivalence ratio, initial pressure of premixed gas and Mach number of the shock wave. As a result, the phenomena of combustion wave were classified using a cell-size of steady-propagating detonation wave. For sensitive gases having small cell-size, the detonation wave was directly initiated behind the shock wave even though the Mach number of the shock wave was relatively low. Empirical equations to evaluate a Mach number and temperature behind shock wave were obtained, which are threshold parameters to cause detonation wave behind transmitted shock wave., rights: 社団法人日本機械学会rights: 本文データは学協会の許諾に基づきCiNiiから複製したものであるrelation: IsVersionOf: http://ci.nii.ac.jp/naid/110006655833/

The present paper describes an experimental and numerical works to investigate a noise phenomenon in supersonic flow that are discharged from a convergent-divergent nozzle with a constant area duct. The noise phenomenon of flow is generated by an emission of acoustic tones. The results obtained shows that unlike the frequency of the screech tone due to the shock-cell structures in the jet flow, the one of the acoustic tone due to the shock wave in the nozzle increases proportional to the nozzle pressure ratio. The frequency of the acoustic tone is depending on the distance from the shockwave to nozzle exit.