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Showing papers in "Jsme International Journal Series B-fluids and Thermal Engineering in 1975"


Journal ArticleDOI
TL;DR: In this paper, the mean values of load distribution among the planetary gears are nearly equality, but variations of dynamic tooth loads grow large in the high-speed range, and even if load distribution is equality, it happens that gear tooth dynamic loads largely.
Abstract: In the planetary gear, the inequality of load distribution arises on each planet gear because of random errors of manufacture and assembly. This phenomenon results in an increase of load to each part, the occurrence of vibration, and a drop in efficiency of planetary gear systems. Though there are a number of studies which are connected with load distribution, many of them are static studies. However, in fact, the dynamic behavior of load distribution in driving is complicated because of the influence of the deformation in each part, dynamic characteristic of the system. Therefore, to explain these relations, a systematic experimental work was carried out using Stoekicht planetary gear(Type 2K-H) with spur gears. Consequently, the following items are explained in this paper : (i) The mean values of load distribution among the planetary gears are nearly equality, but variations of dynamic tooth loads grow large in the high-speed range. (ii) Even if load distribution is equality, it happens that gear tooth dynamic loads largely.

72 citations


Journal ArticleDOI
TL;DR: In this article, the effect of the mass of the springs is taken into account and the solution is formulated by the method of the Laplace transformations with respect to both time and space variables, which allows one to analyze all major performance characteristics in the system subjected to an arbitrarily distributed impulsive load.
Abstract: Dynamical behaviours of two beams connected with a set independent springs and subjected to an impulsive load are investigated taking the effect of the mass of springs into account. The solution is formulated by the method of the Laplace transformations with respect to both time and space variables, which allows one to analyze all the major performance characteristics in the system subjected to an arbitrarily distributed impulsive load. As a numerical example, the case of a concentrated half-sine impulsive force applied to the mid point of the upper beam is treated. It becomes evident that the amplitudes of deflection and bending moment in the beams decrease as the mass of the springs increases. The response curves are also compared with those for the mass-less springs of Wikler type. It is found that the similarities between the two responses diminish as the mass of the springs increases.

45 citations


Journal ArticleDOI
TL;DR: In this paper, the performance of a low head air-lift pump used to lift solid particles is analyzed based on the existing theory for an air-water two-phase flow, and the results of computation agree with those of experiments quantitatively.
Abstract: This paper treats the performance of a low head airlift pump used to lift solid particles. The flow inside the vertical pipe of the air-lift pump is a three-phase flow, i.e. air, water and solid mixed flow. It can be analysed based on the existing theory for an air-water two-phase flow. By coupling the momentum equation of flow and the equation of motion of a single solid particle, the problem can be solved numerically. The results of computation agree with those of experiments quantitatively. The performance of a typical air-lift pump for solid particles is calculated using the present method.

43 citations


Journal ArticleDOI
TL;DR: In this paper, 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, and 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.
Abstract: 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.

41 citations


Journal ArticleDOI
TL;DR: In this article, an experimental study on the confluence of two two-dimensional incompressible turbulent jets, issuing from nozzles with angle θ 0 against the nozzle exit plane, has been presented.
Abstract: An experimental study on the confluence of two two-dimensional incompressible turbulent jets, issuing from nozzles with angle θ0 against the nozzle exit plane, has been presented. The axial momentum and the energy flux of the jets along the z-axis perpendicular to the exit plane are calculated by using the measured values of velocity and pressure distributions. It has been shown that the axial momentum flux along the z-axis decreases owing to the confluence, that the energy flux also decreases remarkably owing to the confluence, that the energy flux also decreases remarkably owing to the confluence, and that the decreased values are approximately 40% of the efflux energy of the jet, independent of the ratio of a distance between two nozzles to the nozzle width and θ0. A method of predicting the velocity distribution also has been proposed. The predicted values agreed well with the experimental results.

39 citations


Journal ArticleDOI
TL;DR: In this article, the effect of varying the ratio of the velocities in the central and outside jets on flow pattern was investigated experimentally, and the results showed that the flow fields near the nozzles can be classified in three patterns of the flow according to the velocity ratio.
Abstract: Flow patterns of three two-dimensional parallel jets were investigated experimentally. In order to examine the effect of varying the ratio of the velocities in the central and outside jets on flow pattern, detailed measurements of the flow by a hot-wire anemometer and flow visualization by oil film were carried out. The results obtained are as follows. (1) The flow fields near the nozzles can be classified in three patterns of the flow according to the velocity ratio. 82) There is a specific velocity ratio at which the flow is unstable. (3) The flow patterns by means of visualization agree well with those of the streamlines, qualitatively.

33 citations


Journal ArticleDOI
TL;DR: In this article, the spring constant of the bolt head and the bolt with a nut was analyzed by using the three-dimensional theory of elasticity, and experiments on these deformations were carried out, and the theoretical value was compared with the experimental one.
Abstract: An important point in designing a bolted joint is to know the increment of an axial force produced in a bolt, when a load is applied on an assembly. For this purpose, it is necessary to know the spring constant Kc for a connected part and Kt for the bolt with a nut. In the calculation of Kt, up to now, the deformations of bolt head and nut have not been taken into consideration. A purpose of this paper is to analyze the value of Kt, taking into account these deformation, and to rationalize the design of the bolted joint. Assuming that the bolt head is a finite cylinder and the nut is a finite hollow cylinder, these deformations are analyzed by using the three-dimensional theory of elasticity. Experiments on these deformations are carried out, and the theoretical value is compared with the experimental one. They show a fairly good agreement with each other. Taking into account these deformations, for example, the value of Kt for M24 (clamping length 50 mm) is calculated. It is found that this value is 20% smaller than that of Kt by the conventional method.

33 citations


Journal ArticleDOI
TL;DR: In this article, the shape of the yield surfaces after preloading along various strain paths of straight lines with or without a corner is obtained for an aluminium alloy whose stress-strain relation is not determined uniquely by the effective stressstrain value of Mises-type.
Abstract: The subsequent yield surfaces after preloading along various strain paths of straight lines with or without a corner are obtained for an aluminium alloy whose stress-strain relation is not determined uniquely by the effective stress-strain value of Mises-type. Tests are made by subjecting thin-walled tubular specimens to combined axial load and torsion. The shapes of the yield surfaces are discussed in the deviatoric stress plane. Yield criterion is derived experimentally as a function of the length and the direction of the prestrain path. The criterion can express a rounded corner in the preloading direction, the flattening at the opposite side of the preloading, and the distortion caused by the difference of flow stress values between axial load and torsion, appearing in the yield surfaces obtained by experiment.

31 citations


Journal ArticleDOI
TL;DR: The concept of the equivalent nozzle width which contains the diameter and width of the nozzle can be usefully applied to describe both maximum flow velocity decay and growth of the jet half width with distance from a nozzle outlet as mentioned in this paper.
Abstract: Mean velocity and turbulence together with pressure distributions in a radial free jet flows were studied. By changing diameter and width of nozzles and discharge velocity, the flow pattern were measured. The concept of the equivalent nozzle width which contains the diameter and width of the nozzle can be usefully applied to describe both maximum flow velocity decay and growth of the jet half width with distance from a nozzle outlet. The maximum flow velocity decay and the growth of the jet half width lie on a single curve according to this equivalent nozzle width. In the main region at large nozzle Reynolds number, the maximum flow velocity decays following the same rule as in circular jet, and the growth of the jet half width is in good agreement with that in the two-dimensional jet.

29 citations


Journal ArticleDOI
TL;DR: In this paper, the geometric shapes of the scratched groove were examined in detail and a comparison of the friction force with these was made, and the results of the scratch tests show that the theory is very useful for the derivation of friction force.
Abstract: Scratch friction has been investigated in which the metallic transfer could be neglected. The scratch tests on some metal surfaces were carried out using conical and spherical sliders of hard materials. the geometric shapes of the scratched groove were examined in detail and a comparison of the friction force with these was made. Experiments showed obviously that there is a good correlation between the friction force and the groove shape. The coefficient of friction on the slider face was found to decrease with a decreasing groove depth under an influence of the surface films on the softer metal. An analysis to determine the friction force quantitatively has been developed. This theory specially includes an effect of the height of front ridge formed in front of the slider during scratching on the friction force. The results of the scratch tests show that the theory is very useful for the derivation of the friction force.

27 citations


Journal ArticleDOI
TL;DR: In this paper, 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.
Abstract: 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.

Journal ArticleDOI
TL;DR: In this article, the authors considered a vertical shaft system, in which a shaft is supported by a double-row self-aligning ball bearing at the upper end and by a single-row deep groove ball bearing on the lower end.
Abstract: A rotating shaft system composed of a circular disc, an elastic shaft and two bearings is usually subject to some gyroscopic effect and has four natural frequencies p1p4 which correspond to four modes of whirling motion. Of these four, the first two are of forward precession (p1>p2>0) and the other two are of backward precession (0>p3>p4). We consider a vertical shaft system, in which a shaft is supported by a double-row self-aligning ball bearing at the upper end and by a single-row deep groove ball bearing at the lower end. If the two center lines of the upper and lower bearings are well aligned and if the shaft is situated at the middle of the angular clearance of the lower bearing, the elastic restoring force of the shaft has symmetrical nonlinear spring characteristics. For this rotating shaft system, summed-and-differential harmonic oscillations of the types [2p2p3], [2p2-p4], [p2-2p3], [p2-2p4], and [p2-p3-p4], and a subharmonic oscillation of order 1/3 of the type [3p2] can occur. In this paper, these nonlinear forced whirling oscillations are studied experimentally. Furthermore, it is pointed out that the polar coordinates are suitable for representing the nonlinear restoring force characteristics in these whirling oscillations.

Journal ArticleDOI
TL;DR: In this article, the velocity distributions of the swirling flow are governed by a single dimensionless parameter Ω defined by (angular momentum flux)/(axial momentum flux), irrespective of the inlet conditions of flows and wall roughness.
Abstract: Swirling flows in cylindrical ducts were investigated by many researchers to meet practical requirements, but the detailed nature of the flows has not yet been clarified. This paper describes the experimental results of swirling flow obtained in stationary cylindrical pipes. Except the inlet region of the pipes, velocity distributions of the swirling flow are governed by a single dimensionless parameter Ω defined by (angular momentum flux)/(axial momentum flux), irrespective of the inlet conditions of flows and wall roughness. This swirling flow shows three kinds of flow patterns in its course of decay; (1) forced-free vortex type, (2) transitional type, (3) forced vortex type. The strength of the swirl Ω decreases exponentially along the pipe axis and its decrement varies with change of the flow patterns. Shear stresses for these flow were calculated, and also the total amount of flow energy was discussed in connection with wall pressure measured along the pipe axis.

Journal ArticleDOI
TL;DR: An interesting flow phenomenon in a cross-flow impeller, an asymmetrical throughflow in a geometrically symmetrical impeller has been investigated experimentally as mentioned in this paper, and the causes of the throughflow are explained in relation to the flow mechanisms.
Abstract: An interesting flow phenomenon in a cross-flow impeller --- an asymmetrical throughflow in a geometrically symmetrical impeller --- has been investigated experimentally. The causes of the throughflow are explained in relation to the flow mechanisms. Flow was visualized by moire method of topography and solid particles. The transient process of the flow from the starting of an impeller until formation of a large eccentric vortex was observed in details. If Reynolds number is larger than 250, the throughflow occurs in all the types of the impellers experimented. In the steady rotation of the impeller the eccentric vortex rotates slowly around the impeller-axis and flow pattern changes sequentially. The change of flow patterns is essential to the flow of the cross-flow impellers.

Journal ArticleDOI
TL;DR: In this paper, the relation between the alternating fatigue limit σw and the crack length was well expressed by following equation: Rp(c)w = αe(sec πσw/2σy - 1 ) = const.
Abstract: Fatigue tests were carried out on mild steel plate specimens with various lengths of cracks. The relation between the alternating fatigue limit σw and the crack length was well expressed by following equation. Rp(c)w = αe(sec πσw/2σy - 1 ) = const. where, Rp(c)w is the cyclic plastic zone size at fatigue limit, αe is the equivalent crack length of an infinite plate, and σy is the yield strength of the material. The size of the persistent slip band zone on the fatigue limit is about one tenth of Rp(c)w and is nearly equal to the measured mean grain size of the material. Rp(c)w has close relations with the crack length corresponding to the fatigue limit of a plain specimen, the material constant which was already obtained in the criteria of fatigue crack initiation at notch roots, and the critical notch root radius at the branch point.

Journal ArticleDOI
TL;DR: In this paper, the effect of three parameters, i.e. h/σ, uτ/U∞ and the width-to-height ratio b/h on the pressure distribution is examined in some detail, where b and h are respectively the width and height of the cylinder.
Abstract: As continuation of the foregoing paper, the present paper describes the flow patterns around the rectangular cylinders immersed in a turbulent boundary layer and the pressure distribution on the surface of the cylinders. The effect of three parameters, i.e. h/σ, uτ/U∞ and the width-to-height ratio b/h on the pressure distribution is examined in some detail, where b and h are respectively the width and height of the cylinder, σ is the boundary-layer thickness, uτ is the shear velocity and U∞ is the free- stream velocity outside the boundary layer. The main results will be summarized as follows : (a) Three sets of measurements of the mean flow and turbulence are presented for the width-to-height ratios of 2.0 and 4.0 with h/σ =1.13 and 0.554. (b) The mean velocity profile in a constant pressure half-jet theoretically obtained by Goertler. (c) The base pressure of the cylinders can be correlated with h in the form of a wall law. (d) The pressure distribution on the upstream face of the cylinders can be represented by a single curve which is irrespective of the width-to-height ratio and the boundary-layer characteristics.


Journal ArticleDOI
TL;DR: In this paper, the authors arranged the experimental results making use of the relation between experimental parameters and critical ignition temperature obtained from a numerical analysis of the fundamental equations and showed that experimental results agreed well with theoretical prediction, since changes in the flow and the composition of mixture around the plate in every experiment under the same conditions are small compared to those in a forced flow.
Abstract: Since the flow velocity in a free convection from a vertical plate is comparatively small, it may be considered that the influence of the divergent flame propagation on the ignition is negligible except in the case of very low burning velocity, and then the inflammable conditions are determined only by the hot surface. It this experiment, changes in the flow and the composition of mixture around the plate in every experiment under the same conditions are small compared to those in a forced flow. Therefore, it is relatively easy to know the qualitative characteristics of ignition. From the point of view described above, the authors arranged the experimental results making use of the relation between experimental parameters and critical ignition temperature obtained from a numerical analysis of the fundamental equations and showed that the experimental results agreed well with theoretical prediction.

Journal ArticleDOI
TL;DR: In this paper, the velocity and pressure distributions of a flow around a cross-flow impeller are derived, which are in good agreement with experimental results on impellers with radial blades, under the assumption that the stability of an eccentric vortex in the radial direction inside an impeller is achieved when an input furnished to the flow by impeller-bladings balances with energy dissipation by fluid viscosity.
Abstract: Using an actuator model, velocity and pressure distributions of a flow around a cross-flow impeller are derived, which are in good agreement with experimental results on impellers with radial blades. Under the assumption that the stability of an eccentric vortex in the radial direction inside an impeller is achieved when an input furnished to the flow by impeller-bladings balances with energy dissipation by fluid viscosity, the stability conditions are discussed. Critical Reynolds number of stability for an axisymmetric vortical flow is given as a function of eccentricity of vortex. Performance of a fan with a simple casing around an impeller is obtained by numerical computation and influences of several parameters on it are clarified. It is found that only one circumferential location of stability of a vortex to make input maximum exists for a given eccentricity.

Journal ArticleDOI
TL;DR: In this article, the preview control problem of vehicle suspension is discussed and the optimal transfer function of a preview filter is determined under a criterion function which is constructed by the weighted sum of the mean squared value of the vertical acceleration on an arbitrary point of a two-dimensional rigid vehicle body and the relative displacement of rear suspension.
Abstract: The preview control problem of vehicle suspension is discussed. The optimal transfer function of a preview filter is determined under a criterion function which is constructed by the weighted sum of the mean squared value of the vertical acceleration on an arbitrary point of a two-dimensional rigid vehicle body and the relative displacement of rear suspension. In some numerical examples, the rms value of vertical acceleration of the center of gravity of the body is reduced to about one seventh that of a system with passive elements only and to about two fifths that of an optimally controlled system without future value of input under the same constraints on relative displacement of rear suspension. It is possible to design this system to be safe side, even under conditions it was not designed for.

Journal ArticleDOI
TL;DR: In this paper, the effect of the side walls of a windtunnel on the flow around a circular cylinder and its wake in the N.P.L. type wind-tunnel having the test section of 60×60×310cm.
Abstract: This paper presents the effect of the side walls of a wind-tunnel on the flow around a circular cylinder and its wake in the N.P.L. type wind-tunnel having the test section of 60×60×310cm. and the dimensions of Karman vortex-street are observed in the water tank. The results are discussed by comparison with those of the investigations so far made.

Journal ArticleDOI
TL;DR: In this paper, the growth of the vortex-pair developed behind a circular cylinder was investigated experimentally, when the cylinder was moved impulsively in a water tank, and the experimental conditions were Re = Ud/ν = 1022×103, d/h = 0.040.
Abstract: The growth of the vortex-pair developed behind a circular cylinder was investigated experimentally, when the cylinder was moved impulsively in a water tank. The experimental conditions were Re = Ud/ν = 1022×103, d/h =0.040.67 where U is the cylinder speed, d the cylinder diameter and h the distance between side walls of the tank. The detailed patterns of the vortex sheets and path lines around the cylinder were visualized by means of electrolysis and Al-dust methods. When the ratio d/h is decreased to 0.1, the effects of the tank walls on the flow are substantially negligible. The vortex sheets roll up near the separation points when Re> 520 and a secondary small vortex-pair is formed on the upstream side of the main vortices. The pattern of the vortex sheets shedding from the secondary vortices changes as Re is increased. This phenomenon is closely related to the manner of growth and collapse of the main vortices. The wall effects were examined within the range of d/h = 0.10.67. When d/h>0.5, the separation of flow occurs also at the side walls and "wall vortices" are formed. These vortices deform the pattern of main vortices behind the cylinder.

Journal ArticleDOI
TL;DR: In this paper, an anisotropic yield condition and a flow rule of metal for various complex loadings were investigated in the three dimensional deviatoric vector space, where the yield function was derived by considering the distortion and the translation of the yield surface.
Abstract: An anisotropic yield condition and a flow rule of metal for various complex loadings were investigated in the three dimensional deviatoric vector space. The yield function was derived by considering the distortion and the translation of the yield surface. The configuration of distorted yield surface was represented as a set of points on a series of ellipses whose lengths of the minor axis were changed as a function of the co-ordinate on the symmetrical axis of the yield surface. The subsequent yield surface after the pre-strain path with a corner was assumed to translate in the direction of the stress increment vector. The flow rule was introduced from the normality rule of the plastic strain increment. The yield surfaces and the stress-strain relations along the proportional pre-loading path, the pre-strain paths with a corner and the cyclic loading path were calculated by using the derived yield functions. There was good agreement between the results of calculation and of experiment for brass.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the pressure distribution on the two-dimensional rectangular cylinders and correlated it with the characteristics of a smooth-wall turbulent boundary layer in which the cylinders are immersed, and found that the contribution of the shear stress on the horizontal upper surface of the cylinders to the total drag is estimated to be a few per cent at most over the entire range of width-to-height ratios tested.
Abstract: Measurement of the pressure distribution on the two-dimensional rectangular cylinders are correlated with the characteristics of a smooth-wall turbulent boundary layer in which the cylinders are immersed. The contribution of the shear stress on the horizontal upper surface of the cylinders to the total drag is estimated to be a few per cent at most over the entire range of the width-to-height ratios tested. For flows with zero pressure gradient, correlations are obtained for the variation of pressure drag with the height of the cylinder h, which are analogous in form to the law of the wall for the boundary-layer velocity profile. The coefficients of the law of the wall for the drag are functions of simply the width-to-height ratio of the cylinder. This law of the wall is valid up to h/σ = 1.37, where σ is the thickness of the boundary layer at the location of the cylinders. The contribution of the base pressure to the pressure drag coefficient is found to be sensitive to the width-to-height ratio of the cylinders, while that of the pressure on the upstream face is almost constant over the entire range of the width-to-height ratios treated in this investigation.

Journal ArticleDOI
TL;DR: In this paper, it is shown that the film thickness between the cylinder and the piston varies exponentially with the longitudinal position along the piston, and the leakage flow rate in the clearance and the frictional force acting on pistons are also shown.
Abstract: 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.

Journal ArticleDOI
TL;DR: In this article, the deformation of the bolt-head and the connected parts under a pressure distribution is analyzed and the spring constant is measured by experiment, and the results show a fairly good agreement between the theoretical and experimental results.
Abstract: In order to fine the spring constant of connected parts in bolted joints, many experimental or theoretical researches have been done. But the theoretical and experimental results show a disagreement. As one of the reasons for this, is considered the deformation of a bolt-head which was included in the value regarded as the deformation of the connected parts. And the traditional theoretical researches have been done under the assumption that a uniformly distributed pressure is applied over the bearing surface. In this paper, using the point matching method coupling with the finite element method, a pressure distribution on the bearing surface is made clear as a contact problem of two elastic bodies, and then the deformation of the bolt-head and the connected parts under such a pressure distribution are analyzed and the spring constant are calculated. In addition, the spring constant is measured by experiment. According to the result, the value of the spring constant that was computed by taking account of the pressure distribution of the bearing surface, is not so different from the result under the assumption of a uniformly distributed pressure and Shibahara and other's theoretical value. When the deformation of the bolt-head is taken into account, the theoretical and experimental results show a fairly good agreement.

Journal ArticleDOI
TL;DR: In this article, the motion of a piston and a cylinder bore are assumed to be geometrically cylindrical and the reciprocating and rotational velocities of the piston are given.
Abstract: 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.

Journal ArticleDOI
TL;DR: In this paper, the free streamline forms an ellipse on the hodogram and the non-steady characteristics of orifices have been analyzed on the assumption that the free line forms a circle.
Abstract: The non-steady characteristics of orifices have been analyzed on the assumption that the free streamline forms an ellipse on the hodogram. The coefficient of contraction is greater than that fro steady flow during the period of acceleration, and smaller during the period of deceleration. In sinusoidal pulsating flow, the mean value tends to be slightly smaller than the steady flow value. The opposite is true for the coefficient of discharge, defined by the instantaneous flow rate and the pressure difference. The experimental results, in which the amplitude of the pulsating flow rate was less than 0.5 and frequency less than 50 Hz, agreed well with the theoretical calculations.


Journal ArticleDOI
TL;DR: In this article, a plastic deformation whose strain trajectory has constant curvature was investigated on mild steel by applying the combined load of axial force and torsion to thin-walled tubular specimen.
Abstract: A plastic deformation whose strain trajectory has constant curvature is investigated on mild steel by applying the combined load of axial force and torsion to thin-walled tubular specimen. The experiment is performed by using a full-automatic complex loading testing machine. Experimental result shows that the relation between the magnitude of stress vector and the arc length of plastic strain trajectory depends mainly on the curveture, and the curve showing such a relation appears higher than the hardening curve for pure torsion. On the other hand, cyclic loading makes the curve lower than the hardening curve for pure torsion owing to the effect of cyclic softening. This may be an experimental evidence that the conventional flow theory is not satisfactory for complex loading. However, the flow theory may be found as a sufficient approximation to plastic deformation under complex loading with strain trajectory of constant radius of curvature larger than 2 percent.