The plane stress problem of an infinite plate, which has a circular hole with a rigid disk inserted in it and is subjected to a uniform tensile or compressive stress distribution at infinity, is treated in this study, assuming that there is neither friction nor cementing between the plate and the disk, and that the diameters of the disc and the hole are identical in the unstressed state. This problem is solved by adopting a numerical method in which the general form of the stress function expressed in the polar coordinates is recurrently used, and numerical results for the stress distributions and the displacement distributions on the contour of the hole are presented.

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Mean-flow characteristics of the turbulent boundary layers disturbed by various rectangular cylinders mounted on a plane wall are experimentally investigated. An empirical law for the mean velocity profile originally proposed by Coles was applied to the disturbed flow field of boundary distributions of the characteristic quantities such as Clauser's equilibrium parameter G, profile paramater II, shape factor H, etc. The values of G, II, H and δ*/δ₀ are found to be rather systematically distributed in the order of the height of cylinders, if h(h/δ₀)C_Dτ is taken as a streamwise length scale for the disturbed boundary layers so that the mean velocity field can easily be predicted in both transient and redeveloping regions downstream of the cylinders. Here δ₀ is the undistubed boundary-layer thickness at the location of cylinders. Here δ₀ is the nudistubed boundary-layer thickness at the location of cylinders, h is the height of the cylinders and C_Dτ is their drag coefficient based on the frictional velocity.

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In the flow of water through a sudden enlargement in a circular section tube, effects of drag reducing additives on losses due to friction and sudden enlargement were studied experimentally. And, in the case that the drag reduction occured in the upstream of drag reduction reappears in the downstream of a sudden enlargement, it was found under a certain condition that the drag reduction reappears in the downstream of a sudden enlargement, the distance of pressure recovery in the rear of a sudden enlargement lengthens and the sudden enlargement factor decreases. From discussions of experimental results, we also found that the relationship between rate of drag reduction (D_r*) and wall shear stress at the onset point of drag reduction (τ_w*) in circular section tube flows prior to a sudden enlargement was useful in the characterization of above mentioned phenomena.

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A study has been made of a flow at and after an attaching point of a radial attaching jet flow on an adjacent offset disc plate. Mean velocity, turbulent velocity and static pressure distributions were measured. The effects of the diameter and width of nozzles, and also of the distance of nozzle center from an offset plate on flow pattern were investigated. A flow field has been divided into three regions : recirculating flow region formed near a nozzle outlet, transitional region where jet center velocity increases downward, and wall jet flow region where jet center velocity decreases with distance. Changes of jet center velocity, thickness of inner layer and jet half width in the wall jet flow region along the flow were measured, and it was found that these results agreed well with those for the radial wall jet flow.

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Characteristics of a Fluxo-type blow tank conveying system for solid materials are examined experimentally. The discharge weight flow rate of the materials is fixed only by the air velocity blown into the tank and it is independent of the free falling velocity of the solid particle. With the weight flow rate being kept constant, the conveying air velocity can be increased by adding air into the pipe at the immediate downstream of the tank. The difference of solids flow pattern in the tank between fine particles and granular materials is visualized by the use of a small scale model tank of semi-circular crosssection.

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Behaviour of a steady laminar wake behind a cylindrical body 10cated in a uniform flow of dilute polymer solutions is analized with linear approximations. The results show that in case of strong viscoelastic behaviour of flow such as past a fine wire, a drag coefficient and a mean Nusselt number do not depend on the Reynolds number but depend on the ratio of elastic to inertial forces and that recovery of wake velocity occurs farther downstream than in case of Newtonian fluid flow.

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Noise sources of an engine can be roughly classified into exhaust noise, suction noise and engine surface noise. The exhaust and suction noise can be effectively reduced by attaching mufflers, but it is not always easy to reduce the noise emitting from the engine surface. The authors come to the conclusion that there is no way except enclosing the engine in a package to drastically reduce the engine surface noise. This paper shows the relation between the noise and vibration of a package enclosing a small engine.

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It is an important but difficult problem to manufacture a special engine which is inherently quiet. So, the question of the day is to reduce the radiated noise by enclosing an engine in a suitably designed package. In this paper, the sound attenuation effect of the package is analyzed theoretically for an enclosed engine, and theoretical equations are obtained for two cases where the dimension of package is very large compared with the wavelength of sound wave and where the dimension is very small compared with the wavelength. Moreover, theoretical analysis is performed regarding the sound transmission loss of various types of package walls and some interesting results are obtained.

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A theoretical analysis was made on the blot loosening mechanism on transversely loaded joints whose clamped parts slip relatively and the following were derived: (1) the condition necessary for the bolts to loosen by self rotation, (2) the physical meaning and the theoretical equation of the critical slippage between the clamped parts, (below which the bolts do not rotate), (3) the theoretical equation of the bolt loosening angle under the above-mentioned condition. Simple experiments were carried out to measure the friction coefficient of the bolts under the transverse slip of the clamped parts. Specifically, the critical slippage between the clamped parts, and the bolt loosening angle with the clamped parts making an arc slip were measured. The theoretical and empirical results were then compared.

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A theoretical analysis was made on the loosening mechanisms of bolts that are at the center of rotation when joints are twisted alternately and the following were derived: (1) the condition necessary for the bolts to loosen by self rotation, (2) the physical meaning and the theoretical equation of the critical angle of relative rotation between the clamped parts (below that angle the bolts do not rotate), (3) the Q-N characteristics under non-rotating loosening caused by fretting wear (Q: clamping force, N: number of loading cycles). Some loosening tests were carried out and it was verified that the theoretical results (1) and (3) qualitatively coincide with the empirical results.

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In this paper, the relationship between the ignition pressure and the increment of axial force in the cylinder-head bolts is analysed theoretically and experimentally, considering the thermal stress which is generated in the steel bolts fastening the aluminium alloy cylinder head of an internal combustion engine. As a result, the following are made clear; the increment of axial force in the cylinder head bolts due to the ignition pressure is very small, but a relatively high thermal stress is generated in the bolt, and the preload loss caused by the permanent set of a new gasket cannot be neglected.

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Author proposes a method of determination of the oil film thickness from the contact behaviors between the rolls and the strip. The oil film thickness at the contact h_con is written as h_con = (the surface roughness of roll) × 1/2 + (the surface roughness of strip) × 1/2 The oil film thickness in rolling is measured by means of a similar method to that proposed by Saeki et al. The measured values are in good agreement with the calculated values. When the oil film thickness is greater than h_con, the reflection in the rolling direction R agrees with that in the transverse direction R₉₀. When that is smaller than h_con, the reflection in the rolling direction is higher. Consequently, a parameter which can represent the lubrication mechanism in cold rolling is derived as α=R/R<90> When α=1, the lubrication mechanism is hydrodynamic and when α > 1, that is boundary.

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The elastohydrodynamic squeeze problem between two cylinders lubricated with grease is studied in the paper. In the analysis, grease is assumed to be a Bingham solid whose plastic viscosity and yield stress are dependent on the pressure, and the effect of surface velocities due to local deformation is considered. It is discussed by solving the time-dependent elastohydrodynamic equation for a Bingham solid with an iterative procedure how the core formation which is the inherent property of a Bingham flow affects the film pressure and the deformation of cylinder surfaces. Using an interferometric method of measuring the separation of a cylinder dropping onto the lubricated optical flat, the film profiles between them are photographed by a high speed cinecamera. The results are compared with the analytical ones.

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In this paper, first if was clarified how to evaluate the effect of heat transfer to ball-fixtures through steel ball surfaces on bulk temperature rises of steel balls in operation and then using the result an equation to calculate maximum contact surface temperature considering bulk temperature rises in operation was given. After the examination of experimental results obtained by a Shell type Four Ball Machine and calculated results, the following conclusions are deduced. The larger the contact surface area is, the greater the effect of bulk temperature rises of steel balls on maximum contact surface temperature becomes. Quantities of heat transferred to ball-fixtures amounted to 40 percent of supplied heat quantity in the case of stationary steel ball and as much as 70 percent in the case of rotating steel ball, and so in calculation of bulk temperature rise of steel ball in operation they cannot be ignored.

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The lubrication mechanisms were investigated in a modified plane strain compression test where the friction is also measured by simultaneous sliding of one of the dies in the strip-width direction. Though the average film-thickness of lubricant trapped between tool and workpiece agreed well with the theoretical calculation based on the squeeze effect, the subsequent behaviors of lubricant seemed to change with the viscosity under the pressure given and the shear rate. Lubricants trapped in small pits on the deforming surface function predominantly hydrostatically when relatively low viscosity mineral oils or vegetable oils are used under relatively low pressures, but develop hydrodynamically considerable shearing stresses on the workpiece and thus even alter the surface micro structures when higher viscosity mineral oils are used under high pressures.

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