This paper is concerned with the stress concentration problem of an elastic solid cylinder with two semicircular grooves under tension. The principal results are as follows: Interference effects of stress concentration due to two notches (a phenomenon leading to α₂/α₁ < 1.0) appear in the condition b/c< 0.5 and are larger for smaller values of b/C, where C and b are radii of the cylinder and the semicircular grooves and α₁ and α₂ are stress concentration factors for one and two notches, respectively. in the condition of b/c > 0.5, there are cases of α₂/α₁ > 1.0, as was suggested by Nisitani et al. for an infinite number of periodic notches. The interference effects of two notches are smaller than those of periodic infinite notches and larger in tension than in torsion. The method of solution used here is an application of Green's functions for axisymmetric body force problems of a solid cylinder.

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In former papers, a concept of crack energy density ε was proposed as the most fundamental parameter in fracture mechanics and it was shown that εεεεε can be evaluated by a path independent integral ε_J without any restriction on constitutive law. In this paper, ε_J -integral is applied to elasto-plastic crack problems under monotonic or cyclic loading; and the availabilities of ε_J -integral are demonstrated. First, it is shown that the physical meanings and applicable ranges of J and ΔJ can be clarified in the light of ε_J. Next, the method of the estimation of ε based on ε_J is established through the finite element analysis of elasto-plastic crack under monotonic loading. Moreover, an analysis under cyclic loading is carried out, and the basic characteristic of ε and the relations between ε and fatigue parameters ΔK and ΔJ are discussed.

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Some typical and common features of history effects on plastic behaviours of polycrystalline metal observed in systematic experiments are analyzed from a view point of crystal plasticity. The single crystal component is selected as one of a face-centered cubic type. A simple mechanical model of polycrystal proposed in this paper reproduces qualitatively well the experimental results. This fact suggests that complex history effects observed in macroscopic experiments can be understood maily by a combination of some simple and fundamental deformation mechanisms of single crystal components. In this paper, a special postulate of isotropy proposed by Ilyushin is also confirmed to be valid with a reasonable accuracy by using the mechanical model of polycrystal.

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A numerical method (inverse method) was developed for a gas-particle supersonic flow past two-dimensional blunt bodies. This method is based on two transformations (von Mises and additional one), which are convenient for determining the shock layer flow field and the body shape. Using the present method, the pure gas flow field around a circular cylinder was first solved numerically for freestream Mach numbers M_∞=3.0, with particle diameter dp=2, 5, 10μm and freestream loading ratios αα=0, 0.2, 0.5 and 1.0, respectively. The effects of dp and α on the shock stand-off distance, the body surface pressure and flow quantities along the stagnation streamline are discussed, and flow patterns in the shock layers are shown.

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Trapped air in a liquid conduit has a great influence on the fluid transients. In this paper, especially its effect on the transient flow rate in a test pipeline is studied experimentally and analytically. Transient flow velocity, following quick opening of a valve attached at the downstream end, was measured. The experiments showed that the transient flow velocity often exceeds the final steady velocity. The numerical calculation by means of characteristics method showed a good agreement with the experiments. Maximum value of the transient flow velocity depends on the volume and the position of the trapped air, and the pressure loss of the pipeline and the valve, and the downstream pressure of the valve. Five dimensionless parameters, which represent above-mentioned factors respectively, are derived. And the relations between the maximum flow velocity and these five parameters are expressed graphically.

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Unsteady aerodynamic characteristics are investigated in detail by analysing chordwise distributions of unsteady pressures obtained on Go-801 airfoil oscillating in pitch with a separation bubble which shows a nature of so-called short bubble. The mechanism of energy transfer between an oscillating blade and an air flow is made clear by utilizing the chordwise distribution of energy transfer, and the effects of the separation bubble on flutter characteristics are clarified. In addition, the validity of potential flow theory is examined and a simple model of a blade oscillation considering the angle of attack relative to main flow is applied to explain the effects of the location of pitching center.

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Unsteady aerodynamic characteristics are investigated in detail by analysing chordwise aspects of energy transfer between a blade oscillating in pitch an air flow at the leading edge stall condition (fully separated flow condition). It is made clear that the simple model of blade oscillation developed in the 1st report for the case of an attached flow is also applicable to the case of the leading edge stall. In addition, semi-empirical improvements are added to the wake model in Shinohara's theoretical analysis which is based on the free streamline theory and the method of singularity. Then, the validity of this theoretical analysis is confirmed by a comparison with experiments.

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Unsteady stall characteristics of a blade oscillating in pitch at an angle of attack near stall region are examined including a dynamic hysteresis phenomenon of stalling in the process of changing the reduced frequency. Effects of this dynamic hysteresis phenomenon on unsteady aerodynamic characteristics of an oscillating blade are made clear in a region where either state of a fully separated flow or an attached (strictly speaking, partially separated) flow persists continuously during the blade oscillation depending upon the history of frequency variation. It is also found that the characteristics of aerodynamic damping are affected remarkably by the dynamic hysteresis phenomenon depending upon the location of pitching center.

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The initial stage of flows due to uniformly accelerated flat plate, elliptic and circular cylinders from rest in incompressible viscous fluids are numerically studied by the finite difference method. The time dependence of stream lines and equi-vorticity lines are shown in flow patterns. The Dufort-Frankel technique is used for solving the vorticity transport equation and the finite Fourier tranform for solving the stream function, which is applied to the analysis of a block tridiagonal matrix equation. The main conclusions are as follows; (1) The Fourier series method is more than ten times faster than the SOR method. (2) Numerical experiments here are in very good agreement with real experiments on a flat plate and a circular cylinder. (3) The length of vortex pairs behind a uniformly accelerated elliptic cylinder at the angle of attack 90° is obtained as a resultant of numerical experiments. (4) The growing process of the secondary vortices behind a circular cylinder is revealed at Reynolds number 731.

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An experimental investigation has been done on trailing and passage vortices downstream of a decelerating cascade. Hot wire traverses gave distributions of secondary flow velocities and streamwise vorticities at four axial locations. A spanwise distribution of passage circulations per unit span agrees well with a prediction by an inviscid classical secondary flow theory. The trailing vortex is well approximated by a vortex sheet immediately downstream of the blade, beginning to roll up at the position of maximum circulation per unit span, It develops into an almost axisymmetric vortex tow chord lengths downstream. The trailing vortex decays faster in the vicinity of the blade trailing edge but more slowly far downstream, than the passage vortex does. The experimental trailing vortex is generated very far away from an endwall as compared with a theoretical position, exerting significant influences on the maximum underturning and the pitch-averaged streamwise vorticity in the main flow region.

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The performance of vaneless diffusers and the flow distribution discharged from the impellers of various specific speed centrifugal compressors were studied. The experimental results of eighteen different stages showed, that (1) the impeller exit flow distortion in axial direction increased with an increase in specific speed, and (2) the pressure recovery of vaneless diffusers for high specific speed compressors was extremely low compared with the value expected by an ideal two dimensional analysis. New type diffusers with half guide vanes on the shroud side wall are proposed in order to improve the pressure recovery of the diffuser under the distorted inlet flow condition. The results show that the pressure recovery of diffuser under distorted inlet flow is considerably improved by half guide vanes, and the best height of the guide vanes is a little less than one half the diffuser width.

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An air-separator as a new means for stabilizing the characteristics in the low flow rate region of an axial flow fan has been studied experimentally. The influence on the performance of this equipment of its parameters such as the structure of the flow passage and dimensions has been examined as well as the influence of hub-trip ratio of the rotor and the aspect ratio of the rotor blades. It is found that the equipment is useful even in such severe conditions that blade separators are useless.

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This report is concerned with results of the systematic experiments which aim to clarify the relation between the behavior of the wake from a circular cylinder within a laminar boundary layer and the boundary layer transition. Main results are as follows. The behavior of the wake is different according to the gap width between a circular cylinder and a flat plate, the boundary layer thickness and the distance from the origin of boundary layer to a circular cylinder, and it is classified into three regions. First, in region I, no vortex shedding from a circular cylinder is found and the process of boundary layer transition is substantially the same as the process caused by a roughness element attached to the plate. In region II, the periodic laminar vortex shedding is observed to decay in propagating downstream and the transition process is similar to one in region I. In region III, the regular vortex shedding develops rapidly in to a turbulent wake and causes boundary layer transition.

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Organized structures including bursting phenomenon of turbulent boundary layer with injection and suction through a slit have been investigated experimentally. Conditional sampling with VITA and quadrant analysis have been applied and space-time correlation has been measured. Moreover, the relationship between bursting phenomenon and wall pressure has been investigated. The results show that the contribution from ejection of bursting phenomenon to mean Reynolds stress -(uv)^^^- near the wall decreases by injection and increases by suction. This is the reason why the mean Reynolds stress near the wall decreases by injection and increases by suction. Space-time correlation of velocities indicates that a coherent structure with oblique angle to the wall exists in the boundary layer. The oblique angle to the wall becomes larger with injection.

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This paper describes the influence of wall roughness on the transition from laminar to turbulent flow occurring in the radial flow of a thin liquid film. The properties of liquid surface was visually observed using the following three types of distributed roughnesses; (A) saw-toothed roughness and (B) trapezoidal shaped roughness, both of which were regularly constructed in a concentric configuration; and (C) irregularly distributed sand roughness. It was found that the point of transition shifted upstream as the height of wall roughness increased under otherwise identical conditions, and that the transition occurred in each of the three regions, namely, (1) the stagnant region, (2) the region in which the laminar boundary layer grows, and (3) the region in which the whole flow is the laminar boundary layer. Furthermore, experimental results showed that the critical Reynolds number decreased as the height of wall roughness increased.

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Experimental investigations on the characteristics of the flow around rectangular cylinders were carried out in the range of subcritical Reynolds numbers. The width-to-height ratio (C/d) of the sections was varied from 0.1 to 4.0. The fluctuating pressure coefficient has a maximum in the same tendency as that of the drag coeffecient when C/d=0.67 and 2.8 become clear. The flow around the cylinder with an arc-like leading-edge corners has been found to agree closely with one around the cylinder with a larger value of the ratio of C/d.

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This paper describes some experimental results about aerodynamic resistance of perforated plates in natural convection, which are useful for designing casings of electronic equipment. Since velocity through a perforated plate and pressure loss are very small in the case of natural convection, the conventional method can not be used to measure the resistance of the plate with reasonable accuracy. Therefore, a new method was developed to obtain resistance coefficients of plates by temperature measurement, since differential temperature between the upstream flow of a perforated plate and the downstream one is related to its aerodynamic resistance. Using the proposed method, further experiments were performed to study the influence of various parameters, such Reynolds number porosity coefficient, and plate thickness/hole diameter on resistance coefficients of perforated plates.

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The melting phenomena of a solid, pressed on a surface with the temperature higher than the melting point, were analyzed and calculated numerically. The analytical results concerning non-dimensional heat flux agreed well with experimental results for water and octadecane shown in the former report. Then, an approximate formula relating non-dimensional heat flux with Stefan number and non-dimensional contact pressure was proposed. The liquid layer thickness distribution between the heat transfer surface and the melting solid, besides the distributions of pressure, velocity and temperature within the liquid layer, was also calculated and discussed.

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The effects of the heat transfer and the generated latent heat of phase transformation on the heat treatment of carbon steel (quenching) are studied analytically and experimentally. The effects of the heat transfer and the latent heat of phase transformation on the results of quenching are found not so simple as generally expected. Thus far, the cooling rate has not yet been exactly defined. Using the instantaneous cooling rate at the A₁ point it is shown that this cooling rate has the most important effect on the microstructure and the hardness of the quenched steel.

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The temperature measurements of nonequilibrium argon plasmas are made in a stacked plasma generator of arc discharge type. Intensity distributions of the N₂⁺ fisrt negative bands, which appear when a small amount of nitrogen gas is added to the plasmas, are measured and compared with computer-generated synthetic ones for determination of rotational and vibrational temperatures. The rotational temperature is well known to be substantially equal to gas temperature. The experiments are performed in a cylindrical positive column under the conditions of discharge currents 20 to 40 A and test section pressures 3.3 to 5.3 kPa. Measured temperatures, which extend up to about 9000 K, reasonably increase as the pressure and discharge current increase. It is also found that at lower pressures the rotational temperatures are much lower than the vibrational and electron temperatures, but they agree with one another at higher pressures, because thermal equilibrium is attained.

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An experimental study was made of the transient characteristics of fuel flow pattern in a carburetor and an intake manifold as well as their effects on the engine performance of a carburetted four cylinder SI engine under transient driving conditions. The results show that the beginning of fuel discharge from the main nozzle of carburetor is delayed by an increase in opening rate of throttle valve. The velocity of liquid fuel film on the wall of intake manifold is expressed as a function of the opening rate of throttle valve θ^^., showing a maximum value at a certain rate θ^^.. The formation of lean mixture is affected much more intensely by the flow delay of liquid fuel film in the intake manifold than by the delay in fuel discharge from the carburetor and this can be avoided by heating the liquid fuel before its supply into the manifold.

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This paper presents a numerical method for free vibration analysis of structures with small design changes or perturbations. The proposed method is an extension of the iteration scheme introduced in the first report of this paper. A subspace technique is employed to deal with variation of degenerate or nearly degenerate eigenvalues of the unperturbed problems. The algorithm is designed such that it can be easily implemented in large-scale finite element computations. To see the effectiveness and fundamental properties of the proposed method, some numerical results are given for lateral vibration problems of a cantilever beam, a circular plate, and a parallelogramic membrane. It is shown that the present approach can actually analyze the separation of degenerate eigenvalues. Furthermore, it can improve the convergence behavior of the iteration process when it is compared with the method in the first report.

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The purpose of this is to establish a measurement method for the fluid force acting on axial turbo machines. The method aims to evaluate the fluid forces as divided into two components, i.e., exciting force and damping force. This method is found to be satisfactory in comparison with other ordinary methods of estimating the fluid force acting on a column test piece in a wind tunnel. According to the results of a test using an axial compressor model with flat blades, the method can quantitatively predict the fluid force acting on rotating blades. Moreover, it is applicable to actual machines.

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This study deals with even multiple vibrations, namely, forced vibrations whirling with even multiple of the angular velocity of a drive shaft. A secondary moment is considered as the cause of the even multiple vibrations and its characteristics are investigated by analyses and experiments. The secondary moment is generated in a universal joint by loads against rotation of a driven shaft and it acts perpendicularly to the driven shaft. The loads consist of a constant resisting moment and a moment for the torsional vibration of the driven shaft based on the mechanism of universal joint. The even multiple vibrations due to the former load differ from those due to the latter load in characteristic.

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Equations of motion of a flexible multi-shaft gear train system are derived in consideration of torsion of axes, gear tooth stiffness, backlash and characteristics of driving source. When input signal is sinusoidal and loads are dry friction, viscous friction and inertia force, dynamic characteristics of a 3-shaft system, as an example, are analyzed theoretically and also investigated experimentally.

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Performance characteristics of large scale tilting-pad journal bearings are examined theoretically and experimentally. Applying a turbulent lubrication equation considering pad deformations and geometrical preload of pad to 2-pads journal bearings, the static and dynamic characteristics of bearings such as Sommerfeld numbers, spring and damping coefficients and unbalance responses of rotor and journal vibrations are obtained. The theoretical results of static characteristics are compared with the experimental ones. It is concluded that pad deformations and geometrical preload of pad have significant effects on the bearing performances under turbulent lubrication conditions and the theoretical results agree well with the experimental ones.

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In this paper, the effects of damping capacity at the chuck-workpiece system on the surface roughness in chatter vibration were investigated experimentally. The damping capacity of the system was varied with several chucking conditions. The results obtained from this study are as follows: (1) The stiffness of the system has a significant influence on the stability threshold of chatter vibration. (2) The damping capacity has an important effect on the surface quality of the machined workpiece. (3) The effect of the damping capacity on the surface roughness can not be expected without a certain guarantee of stiffness.

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This paper aims to clarify workpiece temperature and the mechanism of grinding burn in creep feed grinding. The workpiece is modelled thermally by a three dimensional finite element method. The cooling effect of coolant is measured and the fraction of mechanical energy conducted as heat into the workpiece is estimated by Jaeger's moving heat theory extended to include the cooling effect. The analytical results are shown to agree well with the experimentally obtained temperature distribution. From the experimental evidence that the onset of grinding burn is closely related to the boiling of the coolant used, the mechanism of the grinding burn can be considered as follows; when the grinding zone temperature reaches a point at which bubbles begin to form, the bubbles grow up rapidly in the wheel-workpiece interface and block heat transfer to the coolant. This is verified by the above-mentioned thermal mode.

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The influences of the bearing type and the mounting method of the V pulley on the frequency response of a lathe spindle supported by rolling bearings were experimentally investigated, changing the bearing-preload. Also, the magnitude of the maximum negative real part of the receptance was investigated. Based upon the experimental results, it was found that the damping properties of the work-spindle system are largely affected by the type of the main bearing and the mounting method of the pulley. Particularly, the double-row parallel roller bearing is superior to the tapered roller bearing in the first mode of vibration, but inferior to it in the second and third modes. The damping capacity of the spindle is improved by mounting a floating type V pulley on the rear side of the main spindle

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Synchronization between rhythm and motion is indispensable for both communication in man-machine interface and the efficiency of joint working. In this study, as a fundamental study of the rhythm-motion synchronization, beating a drum in synchronization with an electronic sound or a music is selected. The object of this study is to develop a quantitative method for analyzing the rhythm-motion synchronization, and to demonstrate its effectiveness in terms of sensory evaluations. In the case of the synchronization of motions with a constant rhythm, it is found that motions lead the rhythm, independently of the kind of music and the beating of the rhythm. It is proposed that variability in cardiac cycles of subjects is effective as one of the indices to the working control. In order to grasp the internal state of subjects, electro-cardiogram is measured. It is found that the closer the period of the rhythm is to the characteristic rhythm of the subject, the easier the rhythm-motion synchronization becomes, that is, the less the workload becomes.

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