In order to estimate the error in the low- and high-order plate theories, three-dimensional elastic stress analysis of a thick plate is carried out. The problem treated here is the axisymmetric bending of a clamped circular plate subjected to an annularly distributed load. For this analysis, use is made of the indirect fictitious-boundary integral method. By the examination of the stress distributions in various thickness ratios, the applicability of the classical plate theory as the lowest-order plate theory is investigated and, further, one suggestion for the applicability of the high-order plate theories is presented.

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The applications of boundary integral equation methods (direct methods) to steady-state dynamic problems are investigated. It is shown that in certain cases known integral equations are not equivalent to the elastic boundary value problems, and considerable errors may be occurred in numerical solutions. A technique is developed to obtain modified integral equations, which are always equivalent to the boundary value problems.

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This paper deals with the so-called Reissner-Sagoci problem of an elastic circular finite solid cylinder or a circular thick plate twisted by a pair of annular rigid stamps. For the problem, a method of approach is developed by applying Green's functions for torsional body force and torsional surface force problems of an elastic thick infinite plate. That is, solutions to the problem of a finite solid cylinder are constructed by Green's functions for problems of an elastic thick infinite plate. Stresses, displacements, torques necessary to twist a stamp and torsional forces on the contact plane under the bottom of a stamp for circular solid cylinders or circular thick plates are shown and compared with the results about the Reissner-Sagoci problems of an elastic half space and an elastic thick infinite plate. A comparision with a simple theory of torsion of a circular cylinder is made.

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In order to determine the strength of structures which are required to be leak-tight, when struck by projectile, a series of impact tests for steel plates have been carried out, and an evaluation formula to estimate the critical fracture energy of SGV49 steel plate for SUS304 projectile has been derived so far. In this study, a series of additional tests for steel plates and projectiles of different material were carried out to investigate the effect of each material on the critical fracture energy. As the result, a new evaluation formula which is applicable to other target and projectile materials was derived.

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It is well known that erosion appears behind a circular cylinder due to cavitating flows. It appears in the form of a row. Observation of a trailing bubble which entrains many small bubbles, and measurement of the wall pressure fluctuations were conducted to determine an intermittent spot erosion in the downstream direction. The mechanism the erosion in a row is attributed to slower contraction and re-expansion of the bubble, unlike that of the case of a single spherical bubble. Here, the cavitation flow generated two kinds of pressure shock: one affecting the side wall behind the model, and the other leading to an intermittent erosion in the wake.

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An aerodynamic approach to an optimum compressor cascade in a two-dimensional incompressible flow is described on the basis of two inverse problems; namely, inverse boundary layer problem to produce the optimum velocity distribution and inverse cascade problem to obtain a blade section which realizes a prescribed velocity distribution. A new method for the latter problem is developed in this report. In this method a cascade is transformed into a row of circular cylinders and the blade section is calculated for prescribed velocity distribution, velocity triangle and solidity by solving simultaneous equations about the mapping function. The mapping distortion is exceedingly small in this transformation, and so the inverse problem about the potential flow through a cascade whose solidity, stagger angle and load per blade are high can be solved accurately even near the leading- and trailing-edge.

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Experiments on the total pressure loss coefficient of a cascade in a periodically fluctuating flow generated with a rotating cylinder row are described. similarity of a flow field obtained and one developing after an actual compressor rotor is examined, and the total pressure loss of a test cascade is determined from the measurement of wake profiles using a hot wire anemometer. Total pressure loss coefficient of a lightly loaded cascade in a fluctuating flow increases to 1.11.25 times that in a steady flow. An unstalled range of operation of a cascade enlarges by 3 deg in an incidence with a rise in intensity of the fluctuation. Influence of intensity on the cascade performance is more dominant than that of frequency, but the effect saturats at the intensity 810%.

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Unsteady boundary layers on a cascade in a periodically fluctuating flow have been investigated using an ensemble averaging technique. Time averaged velocity profiles, ensemble averaged instantaneous velocity distributions and turbulence in boundary layers on a test cascade have been obtained. A mechanism of the change in loss characteristics due to a fluctuation has been discussed from the behavior of boundary layers. Boundary layer thickness, 99% thickness, of a lightly loaded cascade remarkably increases with a rise in the intensity of a fluctuation, but momentum thickness is not so affected because some compensating effects occur in a change in velocity profiles. The growth in turbulence in a boundary layer is suppressed by a periodical fluctuation. In the case of a highly loaded cascade, a dynamic stall occurs during a cycle of fluctuation, but the stall is rapidly reestablished as the intensity increases, which causes an enlargement of the unstalled range of operation. However, these effects saturate at the intensity of 810%.

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It is a familiar phenomenon that a small car may be attracted toward a large one when the small one is passed by the large one. It is the purpose of this study to clarify this attraction phenomenon from an aerodynamical point of view. The unstesdy aerodynamical forces generated by an interference of two bluff bodies moving closely are measured by the wind-tunnel-balance. And changes of the yawing moment, the lift and the drag are determined at different speeds, different spacings between the two bodies and different body scales. Moreover, equations of motion for the vehicle are numerically solved by using experimental results with the unsteady aerodynamical forces. The behavior of the vehicle in this unstable situation is discussed for different handling characteristics.

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Swirling flow in a pipe usually has some axi-asymmetricity, detail of which has not been clarified. Here, detailed experimental investigations concerning axi-asymmetric characters of velocity distributions and especially eccentricity of swirl center were performed. Small deviation of velocity distribution from symmetry at inlet section causes non-negligible asymmetricity in downstream section. This increase of asymmetricity in downstream section occurs only in some swirl intensity range. In addition to the velocity distributions, axi-asymmetric character of momentum field and wall pressure were also given.

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Some effects of valve chest on noise and vibrations generated in a test valve are investigated experimentally and theoretically in close relation to flow patterns of internal supersonic air flow and acoustic modes in the valve chest. The test valve consists of a conical plug, a plane seat and a circular chest, and high pressure air is discharged into atmosphere through the valve. The experimental pressure ratio is less than twenty. It is found that the valve chest significantly affects the internal flow, and so noise and vibrations characterized by it are generated. At a relatively large lift and a high pressure ratio, the levels of noise and vibrations increase significantly. This increase is caused by an oscillating conical flow which can be controlled by the characteristics of the valve chest-resonator for certain flow conditions and the geometries. At a relatively small lift, a bending vibration of valve stem is induced by an unstable flow in transition of flow patterns.

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An experimental study on a bubbly two-phase flow has been performed in a horizontal rectangular pipe with rough wall. The bubbles glide under the upper wall, the size of which decreases with an increasing roughness of the wall. The bubble diameter and the bubble population density have been well correlated with F=X^1/3Re^-1K^-1/4, where X, Re and K are quality, Reynolds number and roughness factor respectively. The distorted shape of large bubbles by buoyant force has well agreed with analysis. The bubble velocity is proportional to and lower than the liquid velocity around a bubble. It depends on the size but does not directly depend on the wall roughness.

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The present study investigates the mechanism of falling water limitation under a counter-current flow through a vertical flow path with the experiment of an air/water two-phase flow. The effects of flow path diameter D and length L which are major parameters for the problem are investigated systematically in the experiment. A comparison of the experimental results and the theoretical results reveals that the mechanism is different between a short flow path and a long flow path. The boundary between the short and the long flow paths is located at about L/D=2. For the short flow path, a larger ratio of L/D gives a larger dimensionless superficial liquid velocity J_l* at the same dimensionless superficial gas velocity j_g*. For the long flow path, a larger L/D conversely gives a smaller j_l* at the same j_g* though the effect of D itself is rather small.

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The flow characteristics of a swirling annular-mist two-phase flow induced by a swirler at the entrance of a test section are investigated. The distributions of the liquid film flowrates on the tube wall, the torques of the flow, and the flow angles of the liquid on the tube wall along the tube were measured in an air-water two-phase flow in a tube of 40 mm ID and 5 m length. Empirical formulas for the torque at the outlet of the swirler, the decay of the torque, and the decay of the flow angle along the tube are proposed. Also, the decay of the torque along the tube is analyzed theoretically, and the effectiveness of the swirler for the separation of droplets and the pressure drop by the swirler are presented.

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The liquid film flowrate along a tube (40 mm ID, 5 m length) in swirling downward annular-mist air-water flows, induced by different swirlers at the inlet of the test tube in each run, was measured. The effects of the angle of torsion and length of swirlers, the gas velocity, and the liquid flowrate on the liquid film flowrate along the tube were clarified by experiments. A theoretical analysis of the liquid film flowrate at an outlet of swirler and along a tube was conducted. The calculated results agreed well with the experimental results.

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The heat transfer coefficient decreases remarkably, when a liquid film disappears in the high quality region of evaporating tubes. It is desirable to hold the liquid film on the tube wall by some means. The purpose of this work is to investigate the behaviors of the liquid film and entrained droplets in a non-swirling and in a swirling downward annular-mist air-water flow, induced by a swirler inserted into the inlet of the test section (40 mm ID, 5 m long). This report presents the experimental results on the characteristics of the liquid film along the test section, such as the liquid film thickness, the velocity, and the wave length and the frequency of disturbance waves. Furthermore, the disturbance wave flowrate, the base liquid film flowrate, and the entrained droplet flowrate along the test section are obtained.

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This paper is concerned with a rolling piaton type rotary compressor for air conditioning use. Heat transfer from the cylinder surface to the suction gas in the suction process is investigated. The suction gas heating is experimentally examined by the change of the volumetric efficiency of the compressor when the suction gas temperature is changed while keeping the lubricating oil temperature constart. It is made clear that the volumetric efficiency drop caused by the suction gas heating is 510 % which is equal 1/22/3 of the total volumetric efficiency drop. Based upon that efficiency drop, the heat flow to the suction gas is calculated. It is also calculated using theoretical temperature distribution of cylinder wall. Average heat transfer coefficient in the suction process is estimated in the range of 800 W/(m²·K) ±20 % which is close to the values expected from McAdms' and Adair's correlations.

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In this paper, detailed data on flow fields in premixed jet flames are systematically collected to know their structure over the whole region. It was found from the measurements by LDV that the correlation of axial and radial velocity fluctuations -(u'v')^^^- shows a remarkable negative value near the flame front (F.F.), and that a change in the sign of -(u'v')^^^- occurs corresponding to the rotation of vortex in the downstream of F.F. Concerning the above phenomena, the influences of ambient flow velocity and stoichiometry were also examined.

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The effects of turbulence on the flame propagation in closed vessel were investigated by analyzing the high speed schlieren motion pictures of flames and the pressure changes. Turbulent conditions were prepared by moving a perforated plate quickly once for each experiment, and the characteristics of turbulence were measured by a laser Doppler velocimeter. The main results are as follows: (1) The flame propagation speed and the rate of pressure rise increase with an increasing intensity of turbulence. The volume enveloped by turbulent flame, however, is larger than that by laminar flame at the same mass fraction burned. This fact suggests that turbulent flame has some mass fraction burned. This fact suggests that turbulent flame has some "burning zone", which includes unburned gas cloud. (2) The thickness of burning zone δ_T and the turbulent burning velocity S_T increase with an increasing intensity of turbulence having higher frequency than f₀, where f₀=(S_T/δ_T)/2.

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Measuring the particle sizes and the particle numbers of the adhered particles of fly-ash (mean diameter 2.97 μm) on the adhesive tapes at the various radial positions in the vortex chamber of diameter 140 mm, the mean coefficient of diffusion of the solid particles were estimated by Froude number and by the revolving angle, and the coefficient of variation were estimated by the local inertia parameter and also the standard deviation of the solid particles were estimated by the mechanical equilibrium particles.

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A natural energy autonomous system with an underground water reservoir utilizing solar thermal energy, natural coolness, and sky radiation cooling is presented. The proposed system has two operational modes: i.e. (i) long-term thermal energy storage mode from September to early December, in which solar energy is collected and stored in the underground reservoir and (ii) long-term cool storage mode from April to late June, in which the water temperature of the underground reservoir is cooled by using a sky radiation cooling device, thereby meeting almost all the heating, cooling, and domestic hot water needs in a standard Japanese house. This system is also designed to save domestic water by utilizing rain water. It is especially noted that sky radiation cooling is effectively introduced in the present system, defying the notion that utilization of sky radiation is impossible in the Japanese climate.

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This report deals with flexural vibration of a simply supported beam, along which a body with a pendulum moves slowly at constant velocity. The governing equations of the whole system, which are simultaneous nonlinear ordinary differential equations with slowly varying coefficients, are asymtotically solved by using the method of multiple scales. As the main result, an approximate expression for the deflection of the beam is obtained in the nonresonant case and the maximum deflection is estimated in the internal resonant case. Furthermore the predicted deflections of the beam are confirmed experimentally.

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Vibration of shell of revolution is studied by improved theory. The meridian of the middle surface is a concave circular arc. Under the assumptions of displacements and stresses proposed by Mirsky, the equations of vibration and the boundary conditions are introduced. Rigorous and approximate solutions are obtained and the relations between the frequencies and each parameter or boundary conditions are discussed.

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An elastic rod falling into a vibrating circular cylinder is a model of a control rod falling into a thimble of PWR nuclear reactor core under an earthquake excitation. In this paper, the dynamical behavior of the rod is clarified by taking collision and friction between the rod and the thimble into consideration, and time required for the rod to fall into the thimble is estimated by a simplified analytical model, which is based on the results of a computer simulation. The influences of input acceleration, input frequency, and coefficient of friction upon the falling time of the rod are examined, and it is revealed that the friction at a guide tube located above the thimble plays an important role in determining the falling time of the rod.

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The fundamental nature of the natural frequencies of blades and disk system is studied using a model of the axial vibration of steam turbine blades. The relationship between the vibrations of grouped blades and the disk is discussed in detail. The relations between the number of nodal diameters and the natural frequencies and the transition of natural frequencies according to the change of blade length are clarified. The relationships between the natural frequencies of the grouped blades on a disk and that of a blade alone are also investigated. The natural frequencies of a disk with blades tend to converge towards a constant value related to the natural frequencies of the blade only for an increasing number of nodal diameters.

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Squeeze films between spherical elastic surfaces lubricated by incompressible lubricant under sinusoidal normal motion are numerically analyzed and the effects of the curvature and the squeeze number on the floating height of the thruster, the minimum film thickness and the energy dissipation are investigated. A squeeze film bearing of silicon rubber lubricated by mineral oil is vibrated, and the film pressure and the displacement of the thruster are measured to confirm the theory. It is found that the floating height of the thruster and the minimum film thickness decrease more remarkably with an increase in load in a convex thruster whose lubricating faces are wider than the pressure generating region, the change of the film pressure in one period is very large only at a particular radial position, and this position moves outward with an increase of the load.

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A method to apply the approximation formulae⁽¹⁾ for tooth fillet and root stresses of a thin-rimmed gear to the calculation of stress state of an internal spur gear was developed⁽³⁾. In the case of an internal spur gear which is supported by pinned coupling similar to geared coupling, the tooth fillet and root stresses calculated by this method have shown fairly good agreement with the measured values and the validity of this calculation method has been substantiated. The influences of the supporting conditions, dimensions of the internal spur gear and of the number of planet pinions on the tooth fillet and root stresses have been investigated. It has been clarified from the standpoint of stresses induced in an internal gear that the flexible and distributed supporting of an internal gear such as by pinned coupling and/or geared coupling is better than clamping of an internal gear at some fixed points, e.g., by bolts.

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In order to clarify the initiation and progress of scoring failure on gear tooth flank, scoring tests were carried out using a gear pair of gear ratio 1. The scoring initiates on one tooth pair and then it proceeds or spreads onto successive tooth pairs and finally it covers all the teeth of the gear. The tooth temperature in relation with the driving time takes a steady, saturated value, when no scoring occurs. But when a scoring occurs, the temperature-time curve shows a point of inflection and diverges. These features of scoring phenomena indicate that the analysis of scoring is to be dealt with as a thermal-stability problem.

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To investigate surface failure by scoring or pitting, it is necessary to exactly evaluate the temperature distributions at the surface and in the contacting bodies. In this report, the temperature rise caused by the moving heat sources having various distributions of heat intensity was calculated under the assumption of a three-dimensional heat flow. Further, the degree of the interference between the surface temperature rises when two heat sources move with a constant velocity was examined. From the calculated results it is shown that a considerable degree of the interference between the surface temperature rises caused by the respective heat sources is recognized, and that the surface temperature rise has to be evaluated by means of the three-dimensional heat flow since the effect of the width of the heat source on the surface temperature rise is remarkable.

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