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The load distribution of the fan blade is basic concept to design fan s. The momentum source model is proposed to design the blade geometry. It is checked the performance of the sirocco fan for the various momentum source distributions in previous paper. In this paper, the momentum source distributions for the loaded blade are estimated. The components of momentum sources are checked. It is pointe d out that the momentum sources are mainly derived from the deviation of the flow characteristics . It is cleared for the sirocco fan blade that the spanwise momentum source is almost ze ro and the radial momentum source is very small, but the tangential momentum source is very large. The tangential source is mainly caused by the pressure difference between pressure and suction side of blade. Especially the pressure difference near the leading edge is very large because of the leading edge separation., 長崎大学大学院工学研究科研究報告, 52(98), pp.1-7; 2022

This paper discusses a strength evaluation method of precast multi-story shear wall system which allows slip failure of the vertical joint between wall panels and boundary columns. Shear force of the vertical joint is transmitted by cotters and the joint reinforcements of beam position. Ultimate strength of the wall system is evaluated by adding strength of a wall panel by the calculation method shown in our previous paper and shear forces of the columns. The results of this method were compared with loading tests of the precast wall systems. The calculated values were in good agreement with the experiments.

This paper deals with the flow around a square cylinder with different angles of incidence α. Attention was focused on a range of Reynolds number below 3.1 × 10^4, for which a previous paper reported some Reynolds-number effect on Strouhal number only for 11°. We found that the skewness of the histogram of time series increases in keeping with Re for α～11°. Furthermore, a distinct drop in the cross-correlation between velocity fluctuations and drag coefficient at around α～13° suggested a remarkable difference between upper and lower vortex shedding from the rectangular cylinder.

Since wind-borne debris causes damage in strong winds, it is important to understand flying conditions of debris. In this paper, flying conditions of rectangular flat plates with uniform mass distributions and non-uniform mass distributions was investigated in a uniform flow based on wind tunnel experiments. And flying conditions of plates using a numerical simulation were compared with experimental results. Experimental flying conditions of flat plate with uniform mass distribution coincided with past test results by Tachikawa. Flying trajectories and motions of flat plates with non-uniform mass distribution differs due to an installation angle of plate. Flying conditions of flat plates using our numerical simulation corresponded to experiments in this paper. It seems that our computational method is validated in flying simulation of flat plates.

The purpose of this paper is to simulate the advanced direct shear test by using Distinct Element Method (DEM). The advanced direct shear test is the shearing test suggested by Hajime Matsuoka. Compared with the ordinary direct shear test, when assuming the equal scale simulation this test allows to decrease the number of the particles required. During the analysis, it is confirmed that the shear stress curve declines drastically according to the stick-slip phenomenon. And it is also confirmed that the shear stress and the dilatancy curve vary as the initial position of the particles changes. This indicates that some contrivances are needed to prevent those irregularities. For this, the averaging is suggested in this paper. As a result, the advanced direct shear test is correctly simulated by using DEM. Furthermore, the characteristics of the 2-dimensional DEM simulation such as stick-slip phenomenon and the effect caused by the initial position of elements are revealed., 本研究は個別要素法を用いて砂質土を対象とした簡易一面せん断試験をシミュレーションにより再現すること，および，そこでの個別要素法の特性を把握することを目的としている．本試験を採用することにより，従来の一面せん断試験シミュレーションと比較して，せん断抵抗力の算定法が大幅に変更され，また，同規模の試験を想定した場合，解析に使用する粒子数の低減，解析時間の短縮が期待できる．

In this paper, the Moving-Grid Finite-Volume Method (MGFVM) has been developed and has been applied to various flow problems. The MGFVM is the numerical method suitable for simulations of an unsteady flow driven by moving boundary, such as a body moving in a fluid. The MGFVM is a finite-volume method constructed based on a four-dimensional control-volume in the space and time unified domain (x, y, z, t); therefore, the method satisfies automatically both geometric conservation laws (GCL) and physical conservation laws simultaneously. Three kinds of developments of the MGFVM have been performed in this paper. Firstly, the MGFVM has been extended to unstructured grid system. For compressible flows, it has been developed on both structured grid system and unstructured grid system. For incompressible flows, however, it has been developed on only structured grid system. Thus, in this paper, the detailed formulation of the MGFVM for incompressible flows on unstructured grid system has been described and it has been validated using test problems. Secondly, the MGFVM has been applied to the simulation of fluid-body interaction. As is well known, “Digital Flight” is a recent grand challenge in the research field of computational fluid dynamics. In this paper, as a one of the approaches to the Digital Flight, the simulation procedure of fluid-body interaction using the MGFVM is presented. The MGFVM for fluid-flow solver, the Forward-Euler finite-difference scheme for body-motion solver and the Quaternion for representation of body-rotation are combined in order to solve the system of the fluid-body interaction in the procedure. The approach has been applied to a floating motion of “Fukidama”, a flying motion of “Boomerang”, a fall motion of “Parachute” and a swimming motion of “Jelly-fish”. The results have shown excellent agreement with experimental data. Finally, in order to refine a resolution of flow solutions at discontinuity existing in flow field, a “Neural network” approach has been combined with the MGFVM. The neural network is a system of programs that simulates the operation of the human brain. In this paper, an adaptive mesh refinement has been implemented using the information of the flow discontinuities such as shock wave detected by the neural network of spatiotemporal visual processing. The results have shown good improvement of the resolution at the discontinuities.

Computing a flow around a pitching airfoil, the unstructured moving-grid finite-volume method is developed in this paper. The method has been proposed for various moving boundary problems. However, it is limited for compressible inviscid flows. In the case of calculating a viscous flow at high Reynolds number as a flow around a pitching airfoil, it is necessary to solve a boundary layer. So, a hybrid gird system of a prismatic mesh for boundary layer region and tetrahedral mesh for other regions is suitable. In this paper, the unstructured hybrid moving-grid finite-volume method is formulated in four dimensional space-time unified domain to satisfy a geometric conservation law on such a moving grid in addition to satisfy a physical conservation law. The method is apply to a flow around a pitching NACA0012 airfoil, then the results show that the method is effective for a high Reynolds number viscous flow around a moving body.

An advanced micro-bubble generator with a spherical body in a flowing water tube was invented by Sadatomi in 2003. In the present paper, as an industrial application of the micro-bubble generator, a bubble-jet-type air-lift-pump also invented by Sadatomi in 2005 has been presented together with the results of its feasibility test. In the test, effects of particles size, submergence ratio (=the riser length submerged in water divided by the total riser length), and water and air supply rates to the bubble-jet generator on the pump rerformance have been studied. Yoshinaga-Sato model for predicting water and particles discharge rates has been modified and tested against the present experimental data to confirm its validity. The results of such experiments and analyses are reported in this paper.

The purpose of this paper is to apply a stabilized finite element method using a new bubble element to the unsteady fluid flow expressed by the compressible Navier-Stokes equations to save efficient computational memory for computers. The formulation is based on the mixed interpolation for a transient term. The main idea of the present paper is the mixed interpolation of the transient term with bubble function as the weighting function and with linear function as the interpolation function. The stabilizing effect of the bubble function is effectively used. Temporal discretization is based on the theta method. The formulation leads to the stabilizing effect and efficiency to the unsteady fluid flow problems and is verified by the numerical studies, in which, a shock tube problem, Carter's flat plate problem and compression corner problem are carried out. The present method is shown to be useful for the computation of the compressible viscous flow., 資料番号: AA0063742025, レポート番号: JAXA-SP-07-016

Experimental studies on telescopic aerospikes for aerodynamic control are reported in this paper. Parametric study on the aerodynamic characteristics of the aerospike has performed including the effect of spike length L, base diameter of tip cone D, spike translating speed and direction. The Axial force coefficient Ca of the aerospike suddenly increases at L/D=3.0 due to flow mode transition from the separation to the reattachment. Reattachment/separation flow mode transition phenomenon can be applicable to a newly invented aerodynamic control device, which is called air-breathing aerospike. In this paper, verification test results of this air-breathing aerospike are also reported. A small solenoid valve in the body cylinder successfully controls reattachment/separation flow mode transition at the angle of attacks from 0 to 12 degree. The spiked bodies’ Ca varies according to the mode transition. As a result, we can control the aerodynamic property of the spiked body by opening/closing the valves periodically.

論文(Article), This paper presents the numerical simulation of unstable flow along the surface of a circular cylinder in the Coanda effect. The unstable phenomenon is governed by a nominal Reynolds number Re^*= U_j√ and the nozzle height of the jet, h. In this paper, the changing phenomenon of two-dimensional jet direction is found numerically and is compared with the experimental results. The numerical calculation was carried out by using the finite-difference method for the conditions of unstable phenomenon, that is, 1.0X10^4

In the previous paper, we presented an axisymmetric solution for the stresses and displacements in an elastic thick plate containing an oblate spheroidal inclusion under axisymmetric bending around the z axis normal to the surface of the thick plate. In the present paper, we studied an asymmetric solution for an elastic thick plate containing an oblate spheroidal inclusion under transverse bending. Numerical results are given for different values of size, aspect ratio and stiffness ratio. The stress distributions around inclusion are shown graphically, and are compared with the axisymmetric results.

Piston motion which interacts with lubrication characteristics including friction force between the piston and cylinder has been measured in order to prove the oil whirl phenomena in an axial piston pump and motor which had been found theoretically in the previous paper. The piston motion has been measured by means of eddy current displacement sensors, comparing with calculated results. It has been verified that the piston has whirled in the cylinder under certain operating conditions and specifications, similar to the oiI whirl phenomena as self-excited vibration in journal bearings. The phenomena have not occurred for wide clearance and short sealing part between the piston and the cylinder as the previous paper predicted them. The period of piston whirl has coincided with that of friction force variation.

This paper reports the experimental results of reinforced concrete L-shaped section shear walls that has the maximum load before longitudinal bar of boundary column yields. The stress transfer mechanism of L-shaped section shear wall is discussed and the ultimate strength equation of L-shaped section shear walls is derived. The calculated value by the equation proposed in this paper agrees well with the test results.

The previous study revealed that a nanobubble generator using honeycomb structures may produce a large amount of water including large nanobubble density in a short time. In this paper, numerical simulations are performed for bubbly flow in the honeycomb structure by applying a computational fluid dynamics (CFD) coupled with a population balance model (PBM). The numerical model is based on the Eulerian multiphase model and the PBM was used to calculate the gas bubble size distribution considering the bubble coalescence and breakage. The results show that bubble size distributions in the honeycomb structure under different inlet absolute pressure can be predicted by the PBM. It may be concluded that the maximum shear stress is the main controlling factor for the nanobubble generation.

We present a numerical analysis method for optimization problems of domains in which incompressible steady-state viscous flow field problems are defined. Reshaping was accomplished by the traction method that was proposed as a solution to domain optimization problems in which elliptic boundary value problems were defined. In the previous paper, to total dissipation energy minimization problems we applied the traction method to the Stokes flow field problems ignoring the convective terms. The present paper describes an application of the traction method to the viscous flow field problems including convective terms. For the numerical analyses we employ the finite-element method. The successful results to two-dimensional low-Reynolds-number problems of a bending channel and a channel in which an isolated body exists show the validity of the present method.

In the preceding paper, we reported that the flows around a circular cylinder with a rib are classified into three patterns of re-attached, bi-stable and separated flow. In this paper, it was investigated experimentally the effect of Reynolds number and the scale of rib on the regions of located rib observed each flow patterns, and in case of the bi-stable flow pattern, in order to confirm that the re-attached and separated flow turn alternatively, the pressure distribution along the surface of a circular cylinder are measured. The following properties became evident after examining the experimental results. The value of Strouhal number based on the variation on lift force are small in case of the re-attached flow and large in case of separated flow in compared to a circular cylinder without rib and these values change by the ratio of the duration time of each flow patterns.

A new theory is proposed in this paper explaining the generating of upwellings in ocean currents near the shore and in rivers. Up until now, there have been the bursting phenomenon theory and the cork-boil Eddies theory about upwellings. The proposed theory in this paper is based on the Ekman Pumping theory and is completely different from previous theories. The validity of this newly proposed theory has been proven through numerical calculations.

The present paper was concerned with a part of the series of study on the expansion channel flow by authors. The flow over a backward facing step mounted in a two-dimensional channel was investigated numerically, and was especially examined for the relation between recirculating flow zone length and inflow velocity profile. The Navier-Stokes equation and continuity equation (a stream function-vorticity formulation) were solved by the finite difference method (using the pseudo-unsteady technique). The calculation was performed for the range of Reynolds number Re≦500,and for three cases of different inflow velocity profiles at the step of constant step ratio h/H=0.5 (h and H being step height and channel width respectively). A basic data concerning the effect of inflow velocity profile on the reattachment length has already been reported in our previous paper (1988 and 1993). In this report, relation between the pressure gradient on the wall surface and recirculating flow zone was examined near the reattachment point.

Cold crucible is a levitation melting device, and it is a useful device for melting metal without contamination because the molten metal is levitated by electromagnetic force in the crucible. In this paper, three-dimensional eddy current distributions in cold crucibles are analyzed by using an integro-differential method. In order to reduce computer resources for the analysis of eddy current distribution of the cold crucibles, the authors employed a current sheet approximation for eddy current distribution because penetration depth of the eddy current is relatively small in comparison with the dimension of the conducting bodies. The eddy current distributions approximated by current sheets are solved by an integro-differential method using an electric vector potential. Furthermore, magnetic flux density, power loss, Lorentz force and levitation force of the molten metals are obtained from the solved eddy current distribution. In this paper, eddy current distributions and power loss distributions are investigated.

In this paper, the transonic flow in the throat region of a axially-symmetric nozzle, which is identical with the flow treated in the previous paper, is studied. It is shown that an inner solution to the fourthorder approximation can be derived systematically by the derivation of an outer solution to the ninth-order approximation and by using the methods of matched asymptotic expansions. When comparing the inner solution obtained in this paper with Hall's solution, though his solution corresponds to the present inner solution to the third-order approximation, and in reviewing his work, it was discovered that his axisymmetric solution contained errors in the third-order solution and the ratio of the mass flow. Since his work is widely used in the field, the corrected third-order axisymmetric solution is given. Numerical examples are also given for air (the ratio of specific heats γ=1.4) flowing through nozzles with some values of small parameter E.

In this paper, flow patterns in a circular water tank with three different aeration rates are in estimated by gas and liquid phase flow simulations. As the result, vortex center positions measured from visualization experiments had a good agreement with simulation ones. And when the aeration rates increase, the strength of large vortex increased.

In most of the available work, the Reynolds number based on the step height (step Reynolds number R_) was used as a single parameter that defined the reattachment length (recirculation zone length) in the laminar backward facing step flow. However, B. F. Armaly et al. (1983) suggested that the reattachment length in the laminar backward facing step flow was not a function of a single variable but was more likely to be a function of three or more variables such as the expansion ratio or step ratio, the velocity profile at the step or inlet-section and the step Reynolds number. A basic data concerning this suggestion has already been reported in our previous paper (1988). In this paper, the variation of the reattachment length was examined as a function of the step Reynolds number and the step ratio. For the flow over a backward facing step mounted in a two-dimensional channel, the Navier-Stokes equations and the continuity equation were solved numerically by the finite difference method. The calcuation was performed for the range of step Reynolds number 1≦R_≦250,and for the range of step ratio 0.1≦h_s≦1.0. The calculation results clearly indicated that the reattachment length increased with increasing the step Reynolds number and decreasing the step ratio. In addition, the reattachment length for a constant step Reynolds number in channel with different step ratios was presented and was discussed in order to search for the step ratio on the reattachment length.

In this paper, we propose a method of turbulent flow simulation by D3Q27 Multiple-relaxation-time Lattice Boltzmann method using one-equation SGS model. We apply this method to backstep flow and compare the result with one obtained using the Smagorinsky model.

In this paper, we analyzed the effect of artificial viscosity on the landslide flow distance in the Smoothed Particle Hydrodynamics (SPH) method. Moreover, to show the applicability to an estimation of flow distance, we conducted a two-dimensional simulation of the Aratozawa landslide. As a result, we obtained good agreement with actual damage of flow distance and residual deformation by reducing re-sidual internal friction angle until the shear resistance angle with pore water pressure. It showed that the SPH method considering artificial viscosity could be applied to geo-disasters with large deformation of liquefied ground, such as earthquake-triggered landslides, the lateral spread of liquefied ground, et al.

The aerodynamic noise generated from a perforated metal plate varied by air-flow direction. In the case of expansion type perforated metal plate, it generates very large level aerodynamic noise with a prominent peak in the frequency characteristic. In this paper, velocity fluctuation at some measuring points is measured by a hotwire anemometer to examine its cause. In the experiment, coherent output power (COP) of velocity fluctuation is calculated. The coherence function is defined by the relations between the generated noise and velocity fluctuation of air flow behind perforated metal plate. The expansion type perforated metal plate generates orderly vortex shedding and it brings the vibration of perforated metal plate. The distribution of partial overall value of COP indicates strong correlation with the plate vibration mode. That phenomenon is predicted as lock-in phenomenon between vortex and vibration of the plate.

It is an effective solution to use a bubble eliminator to solve various problems such as cavitation in hydraulic systems. The purpose of this research is to solve the problem in hydraulic system by actively removing air bubbles in hydraulic oil by the bubble eliminator. CFD is one of powerful tools for design of the bubble eliminator having complex flow. It is important to know the dynamic behavior of bubbles in the bubble eliminator in order to remove from the hydraulic oil. In this paper, the accuracy of the performance evaluation for bubble eliminator with CFD has been improved, and the behavior of the fine bubbles which is difficult to remove has been analyzed.

It is proposed the new type turbine for OWC that consists of Wells and Impulse rotors. Wells and impulse rotors are setconcentrically for both high efficiency and starting characteristics. This paper presentsthe concept of the turbine and some geometrical variation withthe numerical simulations in steady flow condition; hub ratio, split duct length and sweep blade. The maximum efficiency is obtained at the low flow coefficient that is fitted to the high-speed operation. The variation of efficiency with flow coefficient is small for large flow coefficient that advantages to the starting characteristics. The maximum efficiency is large at small hub ratio for the flow rate of wells turbine part decreased. The swept blade is not fit for the impulse rotor. The split duct is designed to fit the flow coefficient at the maximum efficiencies of Wells and Impulse turbines. It is pointed out that the geometry of the split duct is important to improve the turbine performance.

Metal cutting operation involves generation of heat due to friction between the tool and the cutting materials. This heat needs to be carried away otherwise it creates white spots. To reduce this abnormal heat cutting fluid is used. Cutting fluid also has an important role in the lubrication of the cutting edges of machine tools and the pieces, and in sluicing away the resulting swarf. As a cutting fluid, water is a great conductor of heat but is not stable at high temperatures, so to improve stability an emulsion type mixed fluid with water and oil is often used. It is pumped over the cutting site of cutting machines as a state of atomized water droplet coated with oil by using jet flow. In this paper, to develop cutting fluid supplying nozzle with ultra-thin oil film coating of water droplet, a numerical analysis of three dimensional mixed fluid jet flows through multi-stage nozzle was carried out by using a finite volume method. Jet flow characteristics such as nozzle exit velocity, development of mixing region, re-entrance and jet intensity were analyzed. Detailed mixing process of air, water and oil in multi-component fluid were also investigated. And the important flow information for advance design of cutting fluid supplying nozzle was drawn.

Planar and non-planar vibrations of Pipes conveying fluid have been studied for a long time as the generic problems of the flow-induced vibrations. However, many of these studies are devoted to the vibrations of the straight pipes conveying fluid. In this paper, as the first step to clarify the dynamics of curved pipes conveying fluid, we study the planar vibrations of a bent part in the articulated pipes due to the pulsating fluid flow. We derive the governing equation of bent part of the articulated pipe conveying fluid consisting of three rigid pipes. From the physical estimation of the governing equation, it is clarified that the bent part of the articulated pipes are forced excited due to the pulsating fluid flow. From the experimental results, theoretical results are qualitatively verified.

Firstly, this paper studies a Direct Yaw Control (DYC) to reduce spin tendency. To reduce load rate of rear tires, a DYC control law to zero cornering force of rear wheels is formulated. Further vehicle response with this control is obtained. This vehicle response is first order delay system. Its time constant value is similar to the time constant with active rear steer control to zero vehicle slip angle at C.G. Since to zero cornering force of rear wheels is equivalent to zero vehicle slip angle at rear wheels, the relation of the position whose vehicle slip angle is zeroed and vehicles behavior is also considered., Ⅲ.論文集, [再録元]自動車技術会秋季学術講演会発表資料

The both viscometers of the usual falling sphere type and the lifting liquid type are based on Stokes’ law. The latter viscometer can be carried out the viscosity measurement at any desired velocity. In this paper, for the lifting ball type, the results of experiments are shown that the coefficient of viscosity calculated by Stokes’ law depended on the lifting ball velocity becomes limiting value when the velocity draws near zero. This simple viscometer of the lifting ball type can be thought of applicable to the student experiment.

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.

Fluid behavior in microgravity (µg) is different from in ground gravity since surface tension and wetting are dominant in µg conditions. In propellant tanks for artificial satellites and future on-orbit spacecraft, sloshing due to disturbance and settling behavior from changes in acceleration have to be understood for the design of the propellant supply system and attitude control system. In this paper, we observed sloshing behaviors in cylindrical containers in µg conditions created by a drop tower facility. In order to investigate the effects of the contact line velocity on dynamic contact angle, we measured dynamic contact angle using a capillary tube. CFD analysis introducing Cox’s equation in consideration of capillary experimental results were also conducted and these results were compared with µg experimental results. Regarding the experimental results, the diameter of the test tank, excitation acceleration, and kinematic viscosity were found to have a significant effect on sloshing behavior in a µg condition. Regarding the comparison between the CFD analysis results and the experimental results, there was a slight difference in the wave shape and the time required for the liquid to reach the top of the test tank. Conversely, there was a qualitative agreement between the fluctuation period and the approximate shape of the liquid surface over time.

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.

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.

In the high-speed flow in duct, the shock wave which has occured when the supersonic flow was decelarated to the subsonic flow interacts with the wall boundary layer. Then, the length of the compression region is lengthened and becomes some times of the duct length. Such a shock wave is called pseudo-shock wave being distinguished from the normal shock wave. It is thought that the interaction problems of shock waves and boundary layers have been learned mainly from the view point of the outer flow aerodynamics such as aeronautics and there are few investigations from the view point of the inner flow aerodynamics, so there remains many unknown points about the behaviour and the structure of pseudoshock waves in ducts. In this paper, pseudo-shock waves in ducts were investigated experimentally and theoretically. Chapter 1 of this paper gives a review of the investigations of shock-boundary layer interactions and pseudo-shock waves. In chapters 2 and 3, the behaviour of pseudo-shock waves in fairly long ducts and at the portion of sudden enlargement of duct area were learned and the results were explained by the theory of one-dimensional adiabatic friction flow. Further, it was reported that there was the history in the behaviour of pseudo-shock at the sudden enlargement portion and that the oscillation of pseudo-shock wave gave great influencies to the duct wall locally. In chapter 4, the structure of pseudo-shock waves of various inflow Mach numbers were ovserved and a diffusion model of pseudo-shock wave was presented which was obtained by reforming Crocco's shockless model. This model could explain the length of pseudo-shock and the pressure distribution along the duct in the region of pseudo-shock wave, and closer agreements between the theory and the experimental data by author and other researchers were obtained. In chapter 5, it was cleared that the pseudo-shock wave in a straight duct was not steady but always oscillating to and fro in the duct, and theoretical considerations of causes and frequencies of the oscillations were presented. Chapter 6 gives the conclusions of this investigation. Finally in the appendix, the basic theories of the high speed aerodynamics in ducts which were used in this paper were summarized.

論文(Article), The problem of oscillation of an incompresible fluid in an open-ended U-tube is frequently discussed in the textbooks of hydraulics, vibrations, and automatic control, etc. Most of them usually give the term of viscous resistance in the kinematic equation of fluid column by using a skin frictional force derived from Hagen-Poiseuille law, which is only applicable to the laminar flow in steady, fully developed motion. But as the flow is dependent on time, it is doubtful if the theoretical equation given in the usual textbooks can explain the experimental results. Therefore, the theoretical kinematic equations using the term of viscous resistance which is derived from not only the case Of laminar flow, but also the case of turbuient flow in steady motion are presented in this paper. And these equations show it impossible to explain the experimental results. Then what sort of explanation for the oscillations of an incompressible fluid in an open-ended U-tube is there? In fact, many theoretical and experimental studies which are different from those in usual textbooks have been taken hitherto, and a brief perspective of the study between 1911 and 1967 is given by J C Biery. And recently a new theoretical study has been presented by D A P Jayasinghe and others. However, it does not secm that tbe definitive solution of this problem has been given. So a new attempt is presented in this paper. On the basis of our experimental results, it is assumed that the deviation from equilliblium fluid level in U-tube is expressed as a second order ordinary differential equation with constant coefficients and the damping factor depends only on Valensi Number. Under these assumptions, it is shown that the approximate formula of the damping factor which may be utilized, at least, in the case of Valensi Numbers ranging from 20 to 180, can be established.

The shear walls with a U shaped section are commonly employed in building structure to resist the forces imposed by earthquakes. A method for analysis of space-frame with open-section shear walls subjected to lateral loading was presented in the authors' previous paper 1). The purpose of this paper is to present a more refine theory on the torsional analysis of U shaped section shear walls considering the shearing strains and deformation. It retains the basic assumption that is given by authors' theory 1). However, St. Venant torsional moment is taken into account exactly.

In orded to search for the influence of roughness on the vascular lesion from hydrodynamical point of view, the flow in a two-dimensional channel with several roughness elements was investigated numerically as a model of the blood flow in an artery with rough surface. Under the condition that the wall of vascular was rigid and the blood was assumed to be Newtonian fluid, the Navier-stokes equation was solved by the finite difference method for the range of Reynolds number of 50≦Re≦2000. From the calculation results, the influence of roughness on the vascular lesion was discussed about the acting shear stress and pressure on the rough wall which were considered as being a source of vascular lesion. A part of the present investigation has already been reported in the Journal of JSME (1986). In this paper, a reconsideration was made synthetically with the some additional data of the flow structure. In addition, an example of experimental result utilizing the flow-visualization technique by authers was also presented in this paper. Good agreement was obtained between the experimental and numerical results for the flow pattern over the rough wall.

application/pdf, In the previous paper, the basic equations of waterhammer were derived in the case of air-entrainment flow in a pressure pipe. In this paper, the method of solution of the basic equation is discussed. And the calculatioin method of mean velocity in the pipe, mean density, modulus of elasticity and speed of pressure wave is described. A geophysical model of analysis is given. And the results of the analytical method used is compared with those of the experimental method, they are almost in agreement., 前報においては, 管内に混入空気が含まれている場合の水撃作用の基礎方程式の誘導を行った. 本論文においては, その基礎方程式の解法を論じた. さらに, 管内流水中に混入空気が含まれている場合の管内平均流速, 平均密度, 弾性係数および圧力波の伝パ速度の計算方法を述べた. また, 解析の幾何学的モデルが提示されている. 本論文において述べた解析方法による結果と実験結果が比較され, これらはよく適合した.

This paper is concerned with a new aseismic design method for building structures named ""Structual Response Control Design using Viscous Damping Walls(in brief VD-Wall)"". The VD-Wall's design formulas obtained from a series of tests using high viscous fluid materials and the practical structure with VD-Walls has experienced some earthquakes. The response analyses for the practical structure, using inelastic time-history dynamic analysis，are executed and the results show good agreements with the observations. Some remarks were derived from these results as follows; 1) This energy dissipator ""VD-Wall"" can provide sufficient damping to structure and reduce the dynamic response of it. 2) The analytical method，presented on this paper，is a simple and sufficiently effective measure to estimate the dynamic response of the structure with VD-Walls. This technology is considered to be practical., 構造工学論文集, 35B, pp.43-55; 1989

In plate bending problems, it is well known that the effects of shear deformation on rectangular and circular plates are studied by the use of Reissner's theory, while the effects of shear deformation and rotatory inertia on dynamic rectangular and circular plates are studied by the use of Mindlin's theory. Their theories have been used with almost strict separation for the cases of static and dynamic plate problems. But, their theories are very similar for almost level of their formulation process with exceptions of difference of shear correction factors and neglection of the terms of time derivatives. The first purpose of the present paper is to propose a refined theory considering to shear deformation, rotatory inertia and thickness normal stress of plate. The second purpose of the paper is to give an account of the modification of Reissner's and Mindlin's plate theories.

In the previous papers, the relationship between the power exerting the combustion chamber wall and the combustion noise power radiated from the outer wall of engine was studied with both a single combustion excitation and running operation. This relationship was denoted by the transmission-radiation coefficient, and was compaired with some different types of engine. In this paper, the vibration transmission coefficient and the noise radiation coefficient were separately obtained as two parts of the transmission-radiation coefficient of the engine structure. The generation mechanisms of combustion induced engine noise were investigated in detail calculating these coefficients for each engine wall and their contributions to the total.

In previous paper, experimental studies were reported to examine the turbulence structure in circular and annulus ducts in turbulent flow region.The behaviour of velocity profile, the turbulence intensity and Reynolds stress were measured by using 2-channel hot wire anemometer.In this paper, flow fluctuation of turbulent component in the axial and radius direction were observed in order to study the scale of the organezed structure of the fluctuation in both channels., 前報では乱流域における管および環状流路内の乱流構造の実験的研究を報告した。そして2チャンネル熱線流速計によって速度分布，乱流強度，レイノルズ応力が測定され，検討を加えた。本報では，軸方向および半径方向の乱流成分の変動の挙動が，両流路内の変動の組織的構造の規模を明らかにするために観察された。

This paper is concerned with a new aseismic design method for building structures named ""Structual Response Control Design using Viscous Damping Walls(in brief VD-Wall)"". The VD-Wall's design formulas obtained from a series of tests using high viscous fluid materials and the practical structure with VD-Walls has experienced some earthquakes. The response analyses for the practical structure, using inelastic time-history dynamic analysis，are executed and the results show good agreements with the observations.Some remarks were derived from these results as follows;1) This energy dissipator ""VD-Wall"" can provide sufficient damping to structure and reduce the dynamic response of it.2) The analytical method，presented on this paper，is a simple and sufficiently effective measure to estimate the dynamic response of the structure with VD-Walls.This technology is considered to be practical.

This paper deals with a longitudinal mixing of particles which are instantaneously releasedin a bounded turbulent shear flow. The movements of particles are described in view of theLagrangian particle analysis. The similarity of concerned phenomena to the turbulent diffu-sion by continuous movements in a uniform turbulent flow is studied. The discrepancy oftwo phenomena is also shown with some discussions. In the mixing the Lagrangian auto-correlation function plays the most important role. Some auto-correlation functions in aturbulent shear flow are introduced and their dependency on a released position and traveltime is discussed. The discussion gives useful information of estimating the Lagrangianauto-correlation function in a turbulent shear flow. Finally, the model of the Lagrangianauto-correlation function proposed by the authors in the other paper is referred, and thegeneral features of longitudinal mixing given by the proposed model are compared withthe past knowledge experimentally obtained.

This paper treats the Parabolized Navier-Stokes equations. We previously solved the Euler equations by finite volume method. The results showed good agreement with experimental results. Then, this was extended to include viscous effect by solving the Navier-Stokes equations, using Beam-Warming scheme. These results also showed good agreement with the Euler code. we also could obtain thermal effect on the Shuttle-like body. In this paper, we employed the PNS equations in order to reduce CPU time. Actually, the calculation time was reduced to some thousands as much as the thin layer Navier-Stokes equations. The two cases were calculated. One is hemisphere cylinder, and another is hemisphere-eliptic cylinder at an attack angle. The first case was compared with the time-dependent thin-layer NS equations. The comparison between them was good. The second case showed clear effect of attack angle such as the turn of flow from the lower surface to the upper surface., 資料番号: NALSP0008006, レポート番号: NAL SP-8