A transversely isotropic hollow cylinder subjected to a ring of radial load is considered within the framework of the three dimensional theory of anisotropic elasticity. A set of two stress functions introduced by Elliot is employed and the method of Fourier transforms is applied to satisfy the boundary conditions. Numerical results show the effects of anisotropy and the ratio of inner radius to outer one on the stress and displacement distributions. The effects of elastic constants on the stress values are also examined.

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To examine the anisotropy of aging under the multiaxial stress state in a mild steel, the strain aged tubular specimens were subjected to combined axial load and torsion. In this paper, mainly the effects of prestrain and aging temperature were examined. The increase in the yield stress due to aging was resolved into two components ; the increase in the lower yield point due to the formation of Cottrell atmosphere and the recovery of elastic limit which was associated with precipitation hardening. By the separation of these two sources of hardening, a quantitative evaluation was made as to the aging effect and the elimination of anisotropy. Furthermore, the yield function containing the third stress invariant, proposed by Edelman and Drucker and partly corrected by the authors, was in good agreement with the experimental results. The direction of the plastic increment vector at the end of yield point elongation was shown to be normal to the yield surface.

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The effect of the vane angles on the performance of a vortex blower as well as on the noise level is investigated. A proper selection of the inlet angle α and the outlet angle β greatly improves the performance ; a combination of α=5°∼30°and β≈15°would be recommended from the viewpoint of the pressure coefficient, the efficiency and the noise level. At the same time, a simple one-dimensional theory is developed based on the angular momentum theory to predict the performance of a vortex blower. The effects of the vane angles, the splitter and the roundness in the corner of the impeller vanes are evaluated in the theory. The calculated results are compared with the experimental results.

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A previous investigation revealed that, when turbulent bursts occur, the instantaneous velocity distribution and friction factor in an oscillating pipe flow are represented by the well-known 1/7 power law and by the turbulent quasi-steady values, respectively. Theses facts suggest that the mechanism of generating turbulence in an oscillating pipe flow is similar to that in a steady flow. Here an evaluation method of the critical Reynolds number is proposed by assuming that the generation region of turbulence is the same as that in a steady flow and by defining that the critical Reynolds number Reos, c is the value when the generation region is built up in a flow field. The estimated results agreed well with the experimental values. In addition, the relation between mean burst period T^^-_B in a steady turbulent pipe flow and critical frequency in an oscillating pipe flow at which turbulent bursts occur was obtained.

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The diffusion of a slightly heated jet issuing from a semi-circular tube into quiescent air along plane wall was studied experimentally. Measurements of instantaneous temperature and three velocity components were made by using a four-element constant-temperature hot-wire probe with digital signal processing. As to time-mean characteristics, the measurements confirm the previous findings that the diffusion in spanwise direction is considerably larger than the one in normal direction in far field. Measurements of turbulence indicate no distinct character in the fluctuations of three velocity components, but it is found that Reynolds stress and turbulent heat flux in spanwise direction are markedly higher than those in normal direction. Three-dimensional mixing-length model is applied to predict Reynolds stress and turbulent heat flux. Though the predicted values in normal direction show good agreement with measurements, the predicted values in spanwise direction are essentially lower than the measured ones.

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Pulsatile flow in a circular pipe can be characterized by three parameters, i.e., the dimensionless frequency, the time-averaged Reynolds number, and the velocity amplitude ratio. Here by changing the time-averaged Reynolds number from 0 to about 2.4×10⁴, velocity measurements were made by means of a hot wire anemometer. From output signals of pulsatile velocity the flows near the transition region were classified into the following three types ; (1) laminar flow, (2) disturbed flow, and (3) turbulent flow. The distributions of oscillatory and time-averaged axial velocity components in each type of flow were characterized with respect to time-averaged Reynolds number.

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Momentum transfer from particles to gas in a decelerated flow of suspensions is confirmed experimentally in a sudden expansion of pipes of different expansion ratios by using different particles, when the flux Richardson number exceeds 0.0015. Mean axial velocity profiles of air in a suspension are measured by a thermistor anemometer in a larger pipe in case of the expansion ratio 0.523, and it is shown that an approximately uniform profile near the maximum pressure point disappears when the flux Richardson number is 2.07×l0^-3.

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By using the results for a two-dimensional jet flow issuing from a finite width nozzle, an approximate calculation of the reattachment flow having various offsets, inclinations of the reattachment wall and initial turbulence intensities was done and compared with experiments. The calculated results of a reattachment distance agree well with the experimental ones in a wide range of offsets, except very small ones. The approximate calculation reveals that the maximum inclination which maintains the reattachment is independent of both the initial turbulence intensity and the offset. The experimental results show that there exist three distinct regions, that is, a natural reattachment region, a forced reattachment region and a non-reattachment region, according to the inclination. Both the results of the calculation and the experiment reveal that the mean bubble pressure shows the minimum value at a certain inclination.

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The dynamic behavior of a submarine cable towed in a uniform sea flow was studied through a 1 km cable towing oceanic experiment. The cable form was obtained by using depth data from seven sensor units fixed in the cable at 100 meter intervals, and the straight distances between two supersonic transmitters fixed to both sides of the ship and seven supersonic receivers in the same sensor units. Cable vibration was measured with a 3-axial accelerometer fixed in the cable 150 meters from the cable end. As the result of the experiment, it was clarified that the submarine cable vibrated owing to a vortex-excited oscillation phenomenon, and that the drag coefficient C_d for the cable was about 1.30∼1.66, which was larger than the C_d (=1.2) for an infinite-length steady circular cylinder normal to a uniform flow.

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The analysis is carried out on the radiative transfer in the real application of a doubly painted layer containing different pigments. The reflective properties for oblique and hemispherical incidences are investigated in the wavelength range from 0.45 to 10 μm. The effects of the scattering properties and volume concentrations of the pigments, optical thicknesses and reflection characteristics of the substrate on the bidirectional and hemispherical reflectances are examined.

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Heat transfer in pulsating laminar flow in a pipe is studied theoretically on the assumption that both the fluid properties and the wall temperature are constant. First, the instantaneous pipe friction factor and the maximum amplitude of pressure-gradient which does not cause a reverse flow are studied. The amplitude of the wall shear stress is represented by a simple equation. Second, the difference in transferred heat between the pulsating case and the steady-state case is studied, and the reason why the locations, where the difference vanishes, appear cyclically in X-direction is explained theoretically. The fluctuations of Nusselt number along X are also illustrated.

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Boiling heat transfer experiments are performed on a Freon 113 upward flow in a uniformly heated tube, and the liquid film flow rate and the size of drops entrained in the vapor core are measured at the exit end of the heated tube. The exit film flow rate at the critical heat flux condition is near to zero in a range of low heat fluxes, but it shows a trend to increase with increasing heat flux over a certain value. An empirical equation for the arithmetical mean diameter of the entrained drops is proposed, and it has been shown that the size distribution of drops can be suitably described by a gamma distribution.

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A frequency analysis technique is proposed to identify various vibrations and noises induced by many impacts in a running engine. The frequency spectra of the vibration and noise which correspond to each impact in a particular time segment within one cycle are discussed by using this technique. According to the result, this technique makes it possible to obtain accurate frequency characteristics of noise radiated in each time segment and the contribution ratio to the total engine noise, and to deduce the band frequency components of vibration and noise which are correlated to each impact produced in the engine structure. Thus it is shown that the analysis technique proposed in this paper gives an effective means to clarify the mechanisms of the engine noise generation.

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This report shows the effects of experimental factors such as the swirl strength, fuel injection period, number of fuel injector nozzle holes and initial fuel injection pressure on the heat release pattern from experimental results by use of a single cylinder, four stroke cycle, medium speed diesel engine. It is clear that while the magnitude of heat release rates is strongly affected by the quantity of residual fuel in the combustion chamber, it is not a suitable factor for analysing the combustion phenomena of a fuel oil spray or the effect of factors involved in the combustion phenomena. Therefore the authors have proposed an effective combustion rate Ke as an analysis coefficient. Ke is not affected by the quantity of residual fuel. Ke includes only the factors required to express the fuel oil spray conditions. Then, the use of the Ke can relate the results of a model test to actual engine performances.

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This paper presents some experimental results on the shape of multiple diesel sprays and the air movement between neighbouring sprays when injected in the quiescent charge with a high pressure at a room temperature. The following conclusions can be drawn from the experiments : (1)The spray tip penetration, the spray cone angle and the equivalent spray angle are not influenced by the sprays located beside the measured spray. (2)The length of initial part and that of penetration part of multiple sprays are greater than those of single spray. (3)Between neighbouring sprays, there is an air movement in the direction of nozzle tip. (4)The air velocity around spray injected between walls is twice as fast as in the case of no wall. (5)The flame growth in the direction of nozzle tip increases as the number of nozzle holes increases.

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Super-summed-and-differential harmonic oscillations in rotating shaft systems are studied theoretically and experimentally. This kind of nonlinear forced oscillation occurred experimentally in the unsymmetrical shaft system carrying a disc and in the unsymmetrical rotor system where the rotor was mounted on a shaft with circular cross section (a round shaft). We have also compared these oscillations with those in the system where a disc is installed on a round shaft. It is concluded theoretically that large unsymmetry of a rotating shaft or a rotor makes it easier for super-summed-and-differential harmonic oscillations to occur in a rotating shaft system. Not only stable stationary oscillations but also unstable ones may occur. The experimental results are consistent qualitatively with those theoretical ones.

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Q-factor is usually a pratical means for predicting maximum amplitude at critical speeds. However, it is not accurate in the case of systems with strong gyroscopic effect, large damping coefficients and asymmetric properties in bearing dynamics. In this study these problems are solved through a new definition of the Q-factor. The unbalance vibration is formulated at each damped critical speed, based upon orthogonality of the undamped critical speed mode, and rearranged by the equation derived from the corresponding damped eigenvalues. The result proves that Q-factor and damped critical speed Ωc are not functions of only modal damping ratio ζ, but also vary with gyroscopic factor γ which is the ratio of modal gyro per modal mass, as follows. [numerical formula1] [numerical formula2] [numerical formula3] The new definition is characterized by value γ reflecting the gyroscopic effect in the system. The value γ=0 is an old and incorrect definition as it does not consider gyroscopic effect. To demonstrate the validity of the method, numerical examples are shown for a 3-disk rotor supported with symmetric and tilting pad type bearings.

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Analytical results on the fundamental critical speed of a shaft in a viscous fluid are presented. When the fluid is set in motion by the shaft whirling, dynamic forces imposed by the fluid on the shaft are obtained by solving the two-dimensional Navier -Stokes equations under appropriate boundary conditions and on the assumption of small amplitude of the whirling motion. Added mass coefficients of the fluid and viscous damping coefficients are determined using these dynamic forces, and accordingly the equations of whirling motion of the shaft are derived. The critical speed of the shaft are found by solving these equations of whirl motion. In this analysis, configurations of the shaft are assumed to be a uniform elastic beam or a diskattached elastic beam, whose both ends are simply supported by bearings. For the latter case, an experimental study was made in order to confirm the analytical results. From this study, it was revealed that the critical speed decreases for large viscosity of the fluid, and when the fluid fills an annulus between the shaft and a cylindrical wall, the critical speed decreases for small annular gap width.

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In this paper, the authors investigated theoretically and experimentally the influence of the fluid inertia forces generated at the restricted part on the dynamic characteristics of externally pressurized circular thrust bearings with capillary restriction. From comperison with the experiment, it may be concluded that the influence on the dynamic characteristics should be considerable when the kinematic viscosity of the lubricant becomes too low, and that the presented analysis yields good predictions for both the bearing stiffness and the damping coefficient in a wide range of designing conditions.

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Although there are many reports referred to the threaded connections subjected to an external load, no reports have fully investigated the contact surfaces. This paper introduces a numerical method to analyse such cases as the threaded connections subjected to a transverse displacement and the flange coupling under an arbitrary type of load for the typical examples of the threaded connections subjected to external load. And the selfloosening mechanism of the threaded connections and the relation between the axial tension and the external load are discussed by the analytical results.

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