This paper is concerned in the analysis of the stress distribution arising a transversely isotropic, homogeneous, elastic half space having two spherical cavities under all-around tension. The traction-free boundary conditions on the plane face and on the surface of the two cavities are well satisfied with the aid of Hankel transforms and the Schmidt method, respectively. Numerical calculations for some practical materials are carried out and the influences of transverse isotropy and geometric configuration upon the elastic stress distribution are presented.

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In this paper, the three-dimensional problems of the short rectangular prism, which are fixed at one end and partially loaded vertically on the upper surface near the opposite end, namely, which are analogous to a cantilever, are analyzed by the use of J.Boussinesq's or an extended H.Neuber's approach. From the result of numerical calculations the following conclusions are obtained. Both longitudinal normal and shear stress distributions vary irregularly in the neighborhoods of the fixed and the loaded ends. In the regions far from those ends the former distributions are nearly linear and the latter ones almost parabolic.

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This paper presents a stress analysis at the root of a bolt thread with pitch error or flank angle error by the finite element method and the copper-electroplating method which are the same methods as mentioned in the previous papers. Firstly, as a three dimensional axially symmetrical problems, the load distribution at the bolt thread which is screwed in a nut thread, is computed by the finite element method comfactor under this load distribution is computed. Secondly, a measuring method of the stress concentration factor by the copper-electroplating method presented in the 1st report, is applied to the bolt threads with four levels of pitch errors or four levels of flank angle errors. The obtained results are as follows : (1) The pitch error has an important effect upon the load distribution and the stress distribution along the bolt thread. Therefore, in order to reduce the stress concentration factor, it is necessary to make uniform the stress distribution at each root of bolt thread. (2) The flank angle error has a little effect upon the stress concentration factor.

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By applying the extended Meyer's law proposed by the author to the relation among the depth of indentation h, the initial load P_o, the major load P_m and the diameter of steel ball D, the following equation was obtained analytically : [numerical formula]where A and n called Meyer's index are constants for the material and P_t=P_o+P_m. The relation was verified as correct experimentally. Furthermore, the effects of errors in P_o, P_m and D on the hardness H_K were calculated from the above relation and verified, and the total error ΣΔH_K due to each permissible error of the tester can be restricted to ΣΔH_K^K/H≒±5 % in the worst case.

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In this paper, the linearized problem of a supercavitating cambered hydrofoil with a jet flap, which is operated near a free surface, is solved by using the conformal mapping technique. Analyses and discussions on the lift and drag coefficients, the cavty configuration and the jet sheet configuration are carried out. The obtained results are as follows : (1) There occurs a lift reduction with a decrease of submerged depth, namely hydrodynamical stable characteristic. (2) The cavity considerably moves up on the hydrofoil by the jet flap, so the hydrofoil thickness can be improved. (3) The drag can be decreased by taking into account the shape of a cambered hydrofoil.

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The structures and the behaviors of shock waves propagating through a gas and solid particle mixture are studied by shock-tube experiments and by two methods of wave analysis. The shock waves concerned are incident on the mixture dispersed uniformly in downstream part of the driven section. Pressures and shock velocities are measured under the condition that the particle loading ratio and the shock Mach number are both less than two. The final equilibrium pressures behind the waves and the velocities of the fully decayed shock fronts agree well respectively with the results of the usual shock theory on the mixture and those of the model analysis on a perfect "effective" gas. The analysis by the method of characteristics is satisfactorily applied to give a good explanation of the observed process whereby a shock wave decays to a weak wave with continuous wave form. And, the authors point out some problems relating to the relaxation process and some inconsistencies of the "effective" gas theory when analyzing the unsteady wave motions.

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The oscillation of a two-dimensional jet attaching to the wall is investigated under the periodic infinitesimal fluctuation in pressure within a bubble between the jet and the wall. The analysis, using a linearized equation of motion, shows that the amplitude of the oscillating jet increase along the jet axis and decreases with an increasing frequency of pressure fluctuation within a bubble. The resonance can not be found between the fluctuation of the pressure and the oscillation of the jet. The phase-lag tends to increase with an increasing frequency of pressure fluctuation. These results are in good agreement with the experimental ones.

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Assuming that a piston and a cylinder bore are geometrically cylindrical and that the reciprocating and rotational velocities of the piston are given, the motion of pistons for piston-type hydraulic machines is analyzed by perturbation method. It is shown that in general the motion of pistons is unstable. Hydraulic lock in spool valves is concluded to be fundamentally caused by the instability of the motion of spools (pistons). For the special case where the motion is stable, the effects of fluid pressure, the piston length, etc. on the radial displacement of pistons are numerically presented.

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In this report the results of test carried out with a rig modeled after a piston pump to varify the theoretical analysis are presented. The friction at the connecting-rod bearings is shown to affect the motion of the piston considerably. It is concluded that the calculated values including the friction coincide fairly well with the test results excepting the low rotational speed-case where the piston comes into contact with the cylinder wall.

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To stabilize the motion of pistons, it is possible to use such a piston that the film thickness between the cylinder and the piston varies exponentially with the longitudinal position along the piston. For piston-type hydraulic pumps and motors the numerical results indicate that in such a piston in which the film is thicker on the high pressure side, both stabilization of the motion and creation of film in the clearance are expectable. It is shown that the load capacity increases by expansion of cylinder due to pressure, while it reduces by projection of pistons out of a cylinder block. The leakage flow rate in the clearance and the frictional force acting on pistons are also shown.

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This study has clarified the relations between the coefficient of additional head loss and valve lifts, and the relations between the pressure distribution and valve lifts. We assume that the total head (head of valve center) is equal to the summation of frictional loss of head in the parallel plate, velocity head at outlet and additional loss of head. For those purpose we have experimented on many valves under the condition of various valve lifts and three fluids; water, kerosene and motor oil. There three fluids are used to expand the equivalent Reynolds number range. The conclusion is that the coefficient of additional head loss in nearly zero but a positive value and gets larger in proportion as valve lifts increase at the same equivalent Reynolds number in the range of the experiments. The pressure distribution at the inlet of valves does not show the same tendency as each valve and it depends on valve lifts.

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By careful measurements of surface-temperature distribution of a uniformly heated circular cylinder in the Reynolds number range 50 to 400, its forced-convection heat-transfer characteristics are related to the behavior of its wake flow. Corresponding to two types of shedding vortices in the wake, the heat-transfer coefficient has two different dependences on the Reynolds number, especially at the downstream side of separation points.

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As a final stage of this study the extinction mechanism is treated qualitatively on the basis of preceeding results. It is found that the partial extinction in the frontal flame zone can be explained with the relation between the first Damkohler number and the maximum temperature on the axis, and that this mechanism is similar to that of laminar opposed diffusion flames. To deal with the overall extinction at the stability limit the excess-reaction variable is found analytically, which has a physical meaning of an overall and average reaction ability of the flame. With this variable and the first Damkohler number three stability curves with different nozzle pressure can be collapsed into a single curve, and the mechanism of extinction at each stability limit can be elucidated independently of the nozzle pressure. It is found that the kind of flame in the stable region depends only on the excess-reaction variable.

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Experimental and theoretical studies on the ignition delay of a single droplet in high pressure gaseous environments were carried out. In the experiments, a movable furnace was dropped over a droplet to cause the ignition and the measurement of ignition delay was made for normal paraffin hydrocarbon droplets at 0 atg40 atg of ambient gas pressure and 220°C700°C of ambient gas temperature. Experimental data were correlated with the following expression. [numerical formula] where P, T, and φ_d are pressure, and temperature and oxygen concentration of ambient gas of which increase makes the ignition delay short. Ignition delay was independent of droplet size and increased with an increase in the number of carbon atom in a molecule of fuel. In the theory, a model was developed for droplet ignition, which consisted of the evaporation of a droplet and ignition of homogeneous gas mixture, and ignition delay was calculated. Both the experimental and the theoretical results showed reasonable agreements.

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Taking link mechanisms as an example of non-uniform motion mechanisms, a dynamic synthesis has been carried out ; dynamic parameters such as masses and spring constants of links have been determined together with kinematic parameters such as length of links such that the errors of outputs at the prescribed performance speeds might become minimum. The synthesis has been applied to a customary four-bar straight-line generator yielding a straight line longer by 52% than the original one. The internal forces and deformations of links and the deviations of outputs caused by the external forces have been also analyzed on general link mechanisms with a single loop.

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