In connection with the stress state of the discontinuous fiber reinforced composite materials or the finite cylinder inserted in a hole, we consider the problem of an infinite body under tension with a rigid cylindrical inclusion of finite length bonded to the inner surface of an infinite cylindrical cavity, within the framework of the three dimensional theory of elasticity. Dougall's stress functions are used and the method of Fourier transforms is applied to satisfy the boundary conditions. The dual integral equations thus obtained are reduced to a linear system of the simultaneous equations of infinite degree by assuming their solutions in a form of the infinite series with the stress singularities.

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The effect of vacuum environment on the creep rupture properties of Inconel 617 was investigated at 1000°C. (1) Creep rupture time of unnotched and notched specimens in 0.3 torr was shorter than that in air in the range of stresses from 3.5 Kgf/mm² to 6.0 Kgf/mm² and the grain sizes from ASTM Nos.2 to 4 tested. (2) This effect resulted from both early initiation and fast propagation of the creep crack in 0.3 torr. (3) It was estimated that both the early crack initiation and the fast propagation in 0.3 torr resulted from an increase of local creep rate at both the notch root of the specimen and the crack tip. (4) It was supposed that the increase of local creep rate in 0.3 torr resulted from the decarburization of the specimen through the non-protective oxide layer which was produced by lack of oxygen it the vacuum.

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Transient response of an inhomogeneous elastic half space to an impulsive torsional load is discussed. Variations of rigidity and density are assumed as the functions of depth, μ/μ₀=ρ/ρ₀=(1+ε_Z)^υ. Exact solutions are obtained for two cases, υ=±2. It is found that there exists a disturbance in a region, where no disturbance is observed in the case of a homogeneous solid. Numerical computations are carried out in detail and they show that the inhomogeneous effect on the response is more remarkable when material parameters increase with depth than when those decrease.

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Theoretical and experimental investigations are reported in this paper, concerning the wake interaction in a turbomachine. Theoretical calculations are made on the unsteady force induced on a cambered blade with angle of attack due to the passing wake of an upstream moving cylinder. The results are compared with the experiments. The reason why discrepancies arise is considered by the experimental data of the three-dimensional unsteady velocity distribution around the blade. Discussions are also made about the wake interaction.

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A numerical method is presented for analysing the unsteady 2-D incompressible laminar flows past an obstacle in a uniform flow. In general, in the methods using the stream function and the vorticity, a unique solution can be obtained only taking account of the one-valued pressure condition. In Part 2, first the method to satisfy this condition for the duct flows proposed in Part 1 is extended to the flows past in obstacle in a free stream. For such flows, it is also important how to treat the outer boundary condition. Therefore, next a pitching method is proposed in which outside of the outer boundary a potential flow is supplemented, the flow is solved analytically, and the solution is patched smoothly to the inside numerical solution. By the mithod the solution satisfying the uniform flow condition accurately can be obtained in a relatively short computer time.

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A finite-difference method is developed for analysing the unsteady two-dimensional incompressible viscous flows around more than two obstac1es in a uniform flow and a duct. In the method the vorticity transport equation and Poisson's equation for stream function are solved, and the values of stream function in the uniform flow and on the duct walls are specified but the values on the obstacles are unknown. These unknown va1ues can be determined from the one-valued pressure conditions for the multi-connected region. In the present paper first a calculating procedure of the stream function on the obstacles is proposed. Then as numerical examples the flows around two square cylinders arranged tandem and side by side in a uniform flow are analysed, and the convergency of solutions and the behaviors of the flows are shown.

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The numerical solution of the flow around an oscillating sphere in a uniform flow is presented. The stream function and the vorticity are expanded in Fourier series with respect to time, which are substituted into the Navier-Stokes equations of motion and the continuity equation. Partial differential equations are obtained from the Fourier coefficients as functions of the spatial coordinates. These equations are solved numerically by finite-difference method. Consequently the plots of the streamlines, the equi-vorticity lines, the hydrodynamic factors and the unsteady drag are obtained.

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The transient flow caused by a rotationally decelerated disk enclosed in a housing is studied theoretically and experimentally, in order to determine the influence of non-steadiness on the flow at the stopping period of the disk. The main results obtained are as follows : During the whole deceleration period there exists, despite the deceleration-rate, a core region similar to that of the steady-state with uniformly decreasing tangential ve1ocity, and its flow pattern is well approximated by a forced vortex. This uniform deceleration of the core is mainly due to the secondary flow in the boundary layer while the disk speed is larger than the core velocity, and due to the radial outward flow induced in the core when the disk speed becomes smaller than the core velocity. The theoretical analysis based on the assumption of a forced vortex gives satisfactory results, though the steady-state characteristics of the boundary layer are used.

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Based on the calculation of our previous paper, the transport characteristics of capsule in pipelines are examined by varying the pipe inlet pressure, pipe length and pipe diameter, and further it is shown that by the use of an exhaust valve placed at the middle of the pipeline an efficient transport of capsule can be achieved. To confirm the numerical analysis some experimental works are carried out and it is found that the numerical analysis is valid. The measurements according to Cudlin and Harman and those obtained with practical capsule pipelines are qualitatively predicted by the present calculation as well.

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The hydraulic, radial force fluctuation acting on the runner of a Francis-type pump-turbine was investigated experimentally. Five model pump-turbines of different specific speeds were tested. In pumping operation, the amplitude of the fluctuation increases as discharge decreases. In generating operation, the maximum amplitude appears with the draft surge frequency during partial load operation. The runner speed frequency component always appears. Components with 0.5 to 1.0 times the runner speed frequency become dominant when maximum amplitude fluctuation occurs during transient operations.

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By measuring stress fluctuations in runner vanes of a prototype 500 m class Francis-type pump-turbine and a 1/12 reduced scale model of that pump-turbine, it was revealed that the stress fluctuations consist of (1) components of higher harmonics of runner speed n, (2) components whose frequencies are constant, that is, independent of runner speed, and (3) components caused by interference from the wicket gates. The 1st components are generated by an unequal distribution of flow properties on the periphery of the runner. The 2nd components are estimated as components of acoustic resonance in flow paths very close to the runner. Comparisons of the prototype and the model are made about the overall amplitude and amplitudes of major frequency components of the stress fluctuations.

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This paper presents some experimental data about evaporating heat transfer in horizontal tubes about 4.75mm I.D. with small internal spiral grooves using R efrigerant R12. The groove inclinations of the tested internal spiral-grooved tubes are 4, 7, 15 and 30 degrees. It is found that a spiral-grooved tube can increase the evaporating heat transfer coefficient in tubes from one and a half times to twice as much as that of a smooth tube for annular flow region, and about ten times due to capillary phenomenon in grooves for stratified flow region.

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A free-piston type rapid compression machine has been developed to simulate combustion process occurring in a diesel engine. A light piston is pneumatically shot and gets hammered in a stop ring at the compression end. A satisfactory performance has been achieved by this device, permitting a near-constant elevated pressure and temperature sufficient to explore ignition of a fuel spray and the subsequent combustion. From a series of tests carried out on this machine, it has been shown that the ignition lag exhibits little or small dependence on pressure and temperature at some elevated pressures and temperatures. It has been also pointed out that in the so-called diffusive burning period, combustion proceeds with self-accelerating rate of heat release in the case when much fuel is allotted to this period, while the rate declines monotonically with time in the contrary case.

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In order to obtain the higher order approximate solutions for steady oscillations of a nonlinear system, a so-called multi-harmonic balance method is suggested, for computing a number of harmonic components simultaneously. The formalization of the computation in the successive approximation is devised by applying the complex Fourier series and the general and detailed procedure is indicated clearly. Using as an example the homogeneous Duffing equation, for which an exact solution is known, the accuracy and the mechanism by which the computational errors occur are discussed. The method is fully examined generally and with regard to the technique of machine computation.

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Thermally induced acoustic oscillations in a pipe have been studied analytically and experimentally. Temperature distributions have been obtained near a heat source in a uniform flow with an acoustic field by solving heat-conduction equations. The temperature change of gas causes a volumetric change, and it may convert thermal energy to acoustic energy under certain conditions which have already been clarified only qualitatively. Using the calculated temperature distributions, the amount of converted energy in a cycle has been computed and proved to be a function of the heat source location, the current velocity, the frequency and the thermal diffusivity of the fluid. Experimental results agreed well with the analysis where the modified current velocity is used considering the boundary-layer around the heater. Some other characteristics of the oscillation have been discovered ; for example, the growth rate of oscillation changes when turbulent transition occurs over a certain amplitude.

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A seismic response analysis method for a cylindrical liquid storage tank subjected to a horizontal earthquake is presented in this paper. The kinetic and strain energies of an empty tank shell are estimated assuming it as an axisymmetric shell. The virtual work of liquid pressure exerting on the tank wall is also estimated analytically by assuming that the behaviour of the liquid follows the velocity potential theory which includes the effect of sloshing. The Lagrangian formulation for the coupled vibration is then derived. Coupling this equation with the Bernoulli equation for the boundary condition of a liquid free surface, an eigenvalue analysis method for the coupled vibration can be obtained. And, a seismic response analysis method is also made using the exciting energy due to a seismic wave. As a result of numerical studies, this solution is proved to be an effective and reasonable method for the seismic response analysis of a cylindrical liquid storage tank.

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In the present paper, the stresses and deformtion at tooth and rim of gears with a thin rim caused by loading on tooth were examined by various experiments and finite element method. Moreover, the bending fatigue strength of gears with a thin rim was compared with that of solid gears. The following conclusions were obtained. (1) The change of stresses at the root fillet of tooth of gears with a thin rim is partial alternating. For this reason the bending fatigue strength is lower than that of solid gears. (2) A practical formla of stresses at loaded side of the root fillet of tooth corresponding to the center of sector hole can be introduced, and consequently the bending fatigue limit of gears with a thin rim can be estimated from the endurance limit diagram.

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Acoustic behaviour of a pair of gears, of 156 teeth with 2mm module, is investigated by means of acoustical holography which is capable of indicating the location and the intensity distribution of sound sources. Several improvements on the system have been performed for the practical measurements, such as applying two hologram planes and a complex hologram. The sound of tooth contact frequency (7.88 kHz) is radiated strongly from the meshing point in the meshing direction with about 100 times greater power than that in the axial direction. Natural vibrations of the gear wheel occur in any conditions, and rotate together with the gear. The sound is produced according to the vibration from a spatially fixed viewpoint, thus the vibration causes two frequency sounds around the natural frequency instead of itself.

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The effect of metal coating on the cutting characteristics was investigated by carrying out experiments employing a single point tool and a grinding wheel coated with a high thermal conductivity metal. It was found that, in the case of a coated single fly-tool, the cutting temperature and the deformation of the work-hardened layer decrease, accompanied by a pronounced effect on the metallurgical structure of the work material. In the case of plunge-grinding with Ni plated wheels, relatively smaller depth of thermally-affected layer and finer roughness of machined surface were obtained, with a large difference in the surface temperature and grinding forces, as compared to those with a normal grinding wheel.

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Sealing performance of gas dynamic seals with rectangular spiral grooves is studied experimentally for the purpose of comparison with the theory previously reported by Sawada. Systematic experiments are made for several seals with various geometries over a wide pressure range from the free molecule to slip flow regimes. A new sealing coefficient for the extremely low pressure range which is based on pressure ratio is proposed and is calculated under the condition of a free molecule flow. Suggestions are made regarding the optimum configurations for the rarefied gas dynamic seal.

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