Showing papers in "Jsme International Journal Series B-fluids and Thermal Engineering in 1960"
TL;DR: In this paper, the aerodynamic properties of a train in a tunnel were analyzed theoretically, during the time interval from the instant of the train head entering into a tunnel to the instant either its tail end coming into the tunnel or the wave front being reflected back to its head, whichever occurs earlier.
Abstract: When a train enters into a tunnel, at first the pressure of the air immediately before the train head rises and the portion of the air with raised pressure spreads forward with a velocity nearly equal to that of sound. In other words the wave front, the boundary surface between the undisturbed air and the compressed air, moves forward, is reflected at the exit of the tunnel and comes back to the train head. In the present paper the aerodynamic phenomena, during the time interval from the instant of the train head entering into the tunnel to the instant either its tail end coming into the tunnel or the wave front being reflected back to its head, whichever occurs earlier, are treated theoretically. The air is assumed to be compreesible and inviscid. The velocities and pressures of air in each portion of the tunnel are calculated. The pressure drag of the train is also obtained. It is interesting to note that the effect of compressibility of air is remarkable in spite of a comparatively low speed of train.
56 citations
TL;DR: In this paper, the authors investigated the rate of heat transfer from the working gases to the combustion chamber walls of the internal combustion engines using a four stroke spark-ignition engine with a water cooled single cylinder.
Abstract: This investigation is concerned with the rates of heat transfer from the working gases to the combustion chamber walls of the internal combustion engines. The test engine used is a four stroke spark-ignition engine with a water cooled single cylinder, bore×stroke being 114.3×140 mm. On the basis of author's experimental results, it was ascertained that the coefficients of heat transfer in this engine agreed well with those which were calculated by Eichelberg's formula [numerical formula] in the expansion stroke, but did not so well in the compression stroke. Law of similarity has been rarely applied to the problems of periodic heat transfer in the internal combustion engines, but recently Karl Elser developed this research. In the present report, improving Elser's method, the relation between the dimensionless groups was found as follows, [numerical formula] where Δs : entropy change Cp : specific heat under constant pressure change θ : crank angle
34 citations
TL;DR: In this paper, a fatigue failure criterion was proposed under a combination of alternating and static stresses on unnotched specimens, and the fatigue test data were then examined to obtain a general fatigue failure criteria, especially on notched specimens with stress concentrations.
Abstract: On unnotched specimens, fatigue failure criterion was proposed under a combination of alternating and static stresses. The fatigue test data were then examined to obtain a general fatigue failure criterion, especially on notched specimen with stress concentrations. It is pointed out that after the stresses have been found for the critical regions, a criterion which uses the applied static stresses and alternating stress must be used to predict whether they are safe.
23 citations
TL;DR: In this article, it was shown that the notion of boundary layer, as in the case of the Newtonian fluid flow, may also be applicable to non-Newtonian flow at high Reynolds number in a wider sense.
Abstract: In this paper, it is first shown that the conception of the boundary layer, as in the case of the Newtonian fluid flow, may also be applicable to the non-Newtonian fluid flow at high Reynolds number in a wider sense R6=(ρV2-(1/n)L1/n)/μpsu1/n(ρ : density, V : characteristic velocity, L : characteristic length, μpsu : pseudo viscosity similar to the viscosity of Newtonian fluid, n : rheological constant) ; and the fundamental equations of motion for non-Newtonian fluid can be simplified by the approximations of the boundary layer equation. Then, the relation between the thickness of boundary layer δ and the Reynolds number R6 can also be deduced as follows : [chemical formula] Moreover, as an example of the analytical treatment by the approximations of boundary layer equation, the flow state in the portion of inlet length of a circular pipe is also analysed by means of variational method. Thus, the respective relations between the inlet length xl, the Hagenbach's correction ΔH of non-Newtonian flow and the rheological constant n have been found by the author's researches.
14 citations
TL;DR: In this article, the authors investigated the relationship between sub-harmonic oscillations and SUMMED and differential harmonic oscillations in a shaft system with non-linear spring characteristics and multiple degrees of freedom.
Abstract: The author has found experimentally that sub-harmonic oscillations and "summed and differential harmonic"oscillations take place in a shaft system with non-linear spring characteristics and multiple degrees of freedom. In the present paper, these vibrations are treated mathematically and analytically. Conclusions arrived at may be summarized as follows : (1) The equation of response curves of sub-harmonic oscillations of order 1/2 has qualitatively the same construction as that of rectilinear vibratory system. The hard or soft spring characteristics result in response curves of both hard and soft spring types. (2) When two vibrations taking place at the critical speed of "summed and differential harmonic"oscillations are both forward or both backward precessional whirling motions, only the summed harmonic type can occur and the differential type does not take place. When "summed and differential harmonic"oscillation consists of forward and backward precessional motions, only differential type has possibility of occurrence.
13 citations
TL;DR: In this paper, the problem of natural vibrations of an isosceles-triangular plate with all edges clamped or with two equal edges and the base edge supported is treated by means of the energy method.
Abstract: The problem of natural vibrations of an isosceles-triangular plate with all edges clamped or with two equal edges clamped and the base edge supported is treated in this paper by means of the energy method, which was applied by one of the authors to the eigenvalue problems of a rhomboidal plate with all edges clamped. Numerical values of the fundamental frequencies are calculated for plates with several contained angles, and they are checked by experiments.
12 citations
TL;DR: In this paper, the discharge characteristics of a cylindrical orifice for high-pressure type air-micrometer were investigated for pressure difference from 0.2 kg/cm2 to 3.0 kg/ cm2 over a range of pressure ratio.
Abstract: The discharge characteristics of nozzle or orifice for high-pressure type air-micrometer were investigated for pressure difference from 0.2 kg/cm2 to 3.0 kg/cm2 over a range of pressure ratio from 0.25 to 0.95. The experiment has revealed the following : 1. By plotting (c : discharge coefficient of incompressible fluid, e : expansion factor) against the pressure ratio, using parameter l/d, a nearly linear relation is obtained. For rounded nozzle, cylindrical nozzle and knife-edged orifice, a change of flow regime occurs respectively at the pressure ratio of 0.53, 0.55, and 0.63. 2. The values of ce at a position where the pressure ratio is equal to 1 agree with discharge coefficients of incompressible fluid over the so-called "limit of constancy"of Reynolds number. 3. Discharge coefficients of each type of nozzle and orifice were collected and one experimental formula is worked out for each. 4. Downstream pressure and temperature are recovered at a position respectively 5 times and 4 times the pipe diameter. 5. Recovery rate of pressure was nearly same as in 1 st Report.
12 citations
TL;DR: In this article, the amplitudes of sub-harmonic oscillations of 1/2 order increase with the magnitudes of eccentricity of the rotating body of a rotating shaft.
Abstract: Lateral vibrations of rotating shaft are recorded, and response curves of sub-harmonic and "summed and differential harmonic" oscillations are experimentally obtained. Summarizing, the amplitudes of sub-harmonic oscillation of 1/2 order increase with the magnitudes of eccentricity of rotating body. Shapes of response curves of sub-harmonic oscillations of forward precession are those of hard spring type, and the response curves of soft spring type are obtained for backward precessional whirling motions. For one critical speed of "summed and differential harmonic" oscillations, the height of peak decreases as eccentricity increases. The other critical speeds have a constant amplitude, even if the magnitude of eccentricity is changed. Shapes of response curves of "summed and differential harmonic" oscillations are either discontinuous response curves with jump phenomena or continuous, as the nonlinear spring characteristics of shaft are changed.
10 citations
TL;DR: In this article, the buckling problem of a simply supported equilateral triangular plate under uniformly distributed compressive and shearing load is solved by the same method as that described in the previous paper.
Abstract: In this report, the buckling problem of a simply supported equilateral triangular plate under uniformly distributed compressive and shearing load is solved by the same method as that described in the previous paper. In the case of uniform compression, the exact solution is obtained by the combined form of trigonometric functions. Further, it is shown that, though the lowest buckling load obtained here coincides with that obtained by Woinowsky-Krieger, their solution is not always correct. In the cases of general loading condition, the solution is approximately obtained by the Galerkin's method. Numerical results obtained are shown in graphical form and in a table.
10 citations
TL;DR: In this article, the basic cutting mechanism in the finishing processes using grains for the cutting edge is investigated for improving the finishing efficiency and for elevating the smoothness of a finished surface.
Abstract: The investigations of the basic cutting mechanism in the finishing processes using grains for the cutting edge are the fundamental measures for improving the finishing efficiency and for elevating the smoothness of a finished surface. The model cutting tests of grains have been carried out under such conditions that the cutting edge angle and the cutting speed may reproduce the original form of the cutting states of the finishing operations such as grinding, superfinishing and single-point cutting. As the result of these tests, the relations between the stock removal or the swell-up and the cutting edge angle or the cutting speed are clarified, and the influence of cutting conditions on the ratio of the tangential and the normal cutting force is found. Moreover, the relation between the cutting mechanism and the cutting speed is obtained.
10 citations
TL;DR: In this paper, the authors measured the characteristics of axial flow pump, the flows before and behind the impeller blades and the pressure distributions on the casing wall near impeller and guide vanes.
Abstract: The essential object of this paper is to know the reasons for the conspicuos increase of the head and brake horse-power of an axial-flow pump at low flow rates. In this report, the characteristics of pump, the flows before and behind the impeller blades and the pressure distributions on the casing wall near the impeller and guide vanes were measured. The results obtained are mainly as follows : 1. When the discharge becomes less than that begins the reverse flow on the suction side of impeller blades, the radial flow in the impeller increases suddenly, and the characteristics of pump change remarkably, too. 2. At that time, the casing wall gives an important effect upon the radial flow in the impeller and the angle between the rotational direction and the relative velocity of the fluid becomes larger than the discharge angle of runner blades near the casing on the delivery side of the impeller.
TL;DR: In this paper, the authors presented the fatigue test by staircase method with small samples, where the step size of the staircase method should be chosen as close to the standard deviation σ of the endurance limit as possible.
Abstract: By the conventional method of the fatigue test, the accuracy of the endurance limit cannot be estimatd. On the other hand, the statistical methods represented by the probit method, the staircase method and so on require a large number of specimens. In this report the fatigue test by staircase method with small samples is presented. The step size of the staircase method should be chosen as close to the standard deviation σ of the endurance limit as possible. When σ is unknown, the following procedure is recommended. The conventional fatigue test is performed in the range where S-log N curve can be replaced by the straight line with a slope. The experimental results are plotted on the S-log N diagram. The linear regression analysis is applied to find σ. The assumptions included in this procedure are discussed. The methods of computing the confidence interval of the mean and the lower tolerance limit of the endurance limit were investigated. The lower tolerance limit of the endurance limit is a statistical concept and the conventional term "lower limit of the endurance limit" is defined from the statistical point of view. Finally these methods were applied to some experimental examples.
TL;DR: In this article, steady, forced vibrations in an unsymmetrical piecewise-linear system with one degree of freedom, whose characteristics of the restoring and damping force are composed of two distinct linear regions, are analyzed by means of a new method utilizing appropriate perfect Fourier series expansion.
Abstract: In this paper, steady, forced vibrations in an unsymmetrical piecewise-linear system with one degree of freedom, whose characteristics of the restoring and damping force are composed of two distinct linear regions, are analysed by means of a new method utilizing appropriate perfect Fourier series expansion. Main features of this method consist in the following procedures : 1) Linearizing the original nonlinear equation of motion by presumedly expanding the nonlinear part of the restoring and damping force into a Fourier series with the same period as of the given exciting force. 2) Obtaining the formal solution of the thus linearized equation by deeming the above-mentioned nonlinear part as if it were an exciting force from without. This solution contains certain unknown coefficients of the Fourier expansion above assumed. 3) Determining these unknown coefficients from the conditions that the above obtained formal solution satisfies the given piecewise-linear characteristics of the system. A certain process of convergency improvement by means of series transformation may prove highly effective in this step.
TL;DR: In this article, the authors introduced the term of heat quantity in the energy equation by applying the conception of the polytropic change, which can be used to calculate the heat flow from the gases to the wall of combustion chamber when the gas cycle is quite similar to the spark-ignition engine.
Abstract: A great many theoretical researches are reported on the periodic heat transmission in the internal combustion engines. Many of them discuss the problem only from the point of view of heat conduction in the solid wall, but there are few reports on the theory of heat transfer in the working gases. H. Pfriem and K. Elser have derived the energy equation of the gases especially in the boundary layer near the cylinder wall and solved it. But they have calculated only the heat transferred from the gas space to the wall under the condition that there were not any heat sources in the gases and the adiabatic compression and expansion were repeated. It is the object of the present paper to introduce the term of heat quantity in the energy equation by applying the conception of the polytropic change. By this means the heat flow from the gases to the wall of combustion chamber can be calculated when the gas cycle is quite similar to the spark-ignition engine. In the latter part of the present report, the numerical calculation is made, and the calculated results are compared with the experimental results.
TL;DR: In this article, the buckling problem of a simply supported triangular plate having inner angles of 30, 60 and 90 degrees under uniformly distributed compressive and shearing load is solved.
Abstract: In this report, the buckling problem of a simply supported triangular plate having inner angles of 30, 60 and 90 degrees under uniformly distributed compressive and shearing load is solved. In the case of uniform compression, the exact solution is obtained by combining the solutions for a simply supported rectangular plate. In the case of general loading condition, the solution is approximately obtained by the Galerkin's method. Numerical results obtained which give the buckling load are shown in graphical form and in a table.
TL;DR: In this paper, the rotary straighteners for straightening round bars and tubes are discussed, and the residual stress distribution in the bar straightened by the straightener represents an alternate vortex of tensile and compressive stress zones around the center of the bar, which is not affected by repeated rotary bending.
Abstract: The rotary straighteners for straightening round bars and tubes are discussed. The author found that the residual stress distribution in the bar straightened by the rotary straightener represents an alternate vortex of tensile and compressive stress zones around the center of the bar, which is not affected by the repeated rotary bending. To obtain better straightness, therefore, the bar has to be bent more severely at the point under the rolls, and receive more multiple rotary bending near the outlet in the straightener. For the rotary plastic bending of the bar, the direction of the bending moment does not coincide with that of the bending of the bar, and there is some angle between both directions, and therefore power is consumed for the rotary plastic bending of the bar. From this point of view, the author derived a formula to calculate the power required for straightening of the bar.
TL;DR: In this paper, the authors investigated the ability of human being as an operator of braking mechanisms and the effect of posture on foot and manual force, delay and transient in handling brake pedals or sticks.
Abstract: Ability of human being as an operator of braking mechanisms was investigated. Effect of posture on foot and manual force, delay and transient in handling brake pedals or sticks, and experimental formulae for these were discussed. For service brakes, 20kg for passenger cars, 30 kg for commercial vehicles may be desirable. It will take less than 1.2 and 1.4 sec for 80% of males and females respectively from stimulus to full application. Posture of passengers and transient of application has prominent effect on riding comfort at braking. Using actuating mechanism developed for this test, fade phenomena during braking on the road and at the dynamometer were observed. Effect of lining characteristics, shoe type, and thermal condition of brake mechanism were calculated using analogue computors.
TL;DR: In this article, simple calculations on heat transfer by the theory of boundary layer in the case where free convection and laminar flow coexist at the same time in the velocity entry length of vertical double pipes with annular space heated from inner pipe are performed.
Abstract: Simple calculations on heat transfer by the theory of boundary layer in the case where free convection and laminar flow coexist at the same time in the velocity entry length of vertical double pipes with annular space heated from inner pipe are performed. In this paper, (I) the temperature distribution and velocity distribution are represented by Bessel functions, (2) f0 (z) the temperature distribution of inner pipe wall is considered. (3) Gauss' method in the numerical integration is applied. These are very convenient in the numerical calculations for Tables of Bessel functions and Gauss' method with high accuracy can be utilized. The theoretical results coincide very well with the experimental results of water heated from the inner pipe.
TL;DR: In this article, the effect of port-angle on the scavenging process inside the cylinder was investigated using a new electronic method in model cylinders of a through-scheduling system.
Abstract: One of the important problems involved in the design of the port arrangement of a through scavenged 2-stroke Diesel engine is that of determining the entry angle of inlet ports. This paper presents the results investigated the effect of port-angle on the scavenging process inside the cylinder by using a new electronic method in model cylinders of a through scavenging system.
TL;DR: In this paper, a regenerative pump performance analysis is presented, in which the flow channel and the impeller dimensions are varied with each other, and the theoretical equations for performance are available for practical purpose.
Abstract: According to the author's preceding research on a regenerative pump, in which the flow channel and the impeller dimensions were widely changed, the pump performance is influenced by their relations. Then, it is obvious that the analysis of performance can not be considered without taking their relations into account, when they vary with each other. The author's analysis consideres their effects on the performance. And he shows that the theoretical equations for performance are available for the practical purpose.
TL;DR: In this paper, the results of the present study together with those obtained in the previous study for the stress ratios less than unity were analyzed in the light of the authors'theory, which aims to relate the strength under dynamic stress to the static creep strength.
Abstract: Dynamic creep and rupture tests were carried out with annealed specimens of a 0.15 percent carbon steel under the combined static and alternating stress with stress ratios (alternating stress/mean stress) of more than unity. The test temperature was 450°C. The results of the present study together with those obtained in the previous study for the stress ratios less than unity were analysed in the light of the authors'theory, which aims to relate the strength under dynamic stress to the static creep strength. The conclusion obtained is summarized as follows : 1. The forms of the dynamic creep curves are similar to those of the static creep curves even for the case of the stress ratio of more than unity. 2. The prediction of dynamic creep rupture strength from the static creep rupture data together with the fatigue data under reversed stress is established over the entire range of stress ratios from zero (static stress) to infinity (reversed stress). This is based on the idea that the damages of material under varying stress are composed both of the creep damage previously discussed and the fatigue damage caused by the dislocation oscillation under alternating stress. 3. The equivalent static stress, which was defined previously to predict the dynamic creep strength from the static creep data in the stage of transient creep, is applicable to the case of creep including the steady state component in addition to the transient component and also to the case of rupture. 4. The influence of the dislocation oscillation due to alternating stress on the dynamic creep was also discussed.
TL;DR: In this article, two methods to delay the separation of flow in short conical diffusers are described, and a method of analysing the effects of the separation positions and boundary layer thicknesses on the loss of flow is described.
Abstract: Two methods to delay the separation of flow in short conical diffusers are described. The 10° conical diffusers, having a suddenly enlarged outlet, have great advantages over the simple conical diffusers of same length, when the equivalent angle of divergence is greater than 20°. When the interior wall near the separation point is roughened, the loss of flow becomes lower than in the case of smooth wall because of delay of separation point. A method of analysing the effects of the separation positions and boundary layer thicknesses, on the loss of flow, is described.
TL;DR: In this article, the critical conditions of wrinkling were considered and discussed for the case where a blankholder was used, and the allowable specific wave amplitude of wrinkles was deduced, and by introducing this into the equilibrium equation, a formula for prediction of the critical blank-holding pressure was induced.
Abstract: In this report, based on the equilibrium equation of moments induced in the first report, the critical conditions of wrinkling are considered and discussed for the case where a blankholder is used. In practice of deep drawing operation, we cannot but often allow arising of small wrinkles in a flange through various causes, but if the wave amplitude of wrinkles is lower than the allowable value, wrinkles do not practically remain in the product, since an effect of suppressing flange wrinkles exists in die radius. Thus, the allowable specific wave amplitude of flange wrinkles is deduced, and by introducing this into the equilibrium equation, a formula for prediction of the critical blank-holding pressure is induced.
TL;DR: In this paper, the results of experiments on flat-seated valves with broader seat-face, discharging water into the air under a constant head of about 194 cm, were presented.
Abstract: This paper presents the results of experiments on flat-seated valves with broader seat-face, discharging water into the air under a constant head of about 194 cm. Five valves were used in all, of which the first four had diameter d smaller than seat-face diameter d1 and the last one had d equal to d1. When the lift of the valves with d d1 on which we have already reported. We try to give some explanations for these phenomena hereunder.
TL;DR: In this article, the frequency n of eddies generated behind a circular cylinder in fluid is expressed by the equation n=S(v/d), where v is the fluid velocity, d the diameter of circular cylinder and S Strouhal's number, which has been treated as the function of Reynold's number.
Abstract: The frequency n of eddies generated behind a circular cylinder in fluid is expressed by the equation n=S(v/d), where v is the fluid velocity, d the diameter of circular cylinder and S Strouhal's number, which has been treated as the function of Reynold's number. Many inverstigators have experimented on the values of Strouhal's number between R6≒3×10∼5×105, but the values between. R6≒2×104∼1×105 have not been obtained. The present authors have experimented on all of them between R6≒6×10∼5×105 by three devices with a high speed tunnel, a low speed tunnel and a water rotating vessel respectively and have made it clear that they take nearly a value of 0.18 between R6=1×104∼1×105, suddenly increasing to 0.3∼0.6 at the point near the critical Reynold's number Rec≒5×105.
TL;DR: In this paper, the authors have shown that the three performance characteristics are closely connected with the types of the flow state, respectively, and the existing ranges of these characteristics can be simply expressed by the outside conditions of ejector.
Abstract: Steam ejectors can have three basic kinds of performance characteristics according to the outside conditions of ejector-driving steam pressure, back pressure of diffuser and flow rate of entrained fluid. From the experimental studies on the flow state in ejectors, it has been shown that the three performance characteristics are closely connected with the types of the flow state, respectively, and the existing ranges of these characteristics can be simply expressed by the outside conditions of ejector. The results of experiment on the effects of the various dimensions of ejector are also presented.
TL;DR: In this paper, the validity of the prediction formula is checked by experiments as much in detail as possible, and the formula has been found satisfactory to predict the critical blank-holding pressure necessary for obtaining a product in which "local wrinkles"remain.
Abstract: In this report, the validity of the prediction formula is checked by experiments as much in detail as possible. Consequently, the formula has been found satisfactory to predict the critical blank-holding pressure necessary for obtaining a product in which "local wrinkles"remain. And also, it has been experimentally confirmed that the value of the allowable specific wave amplitude ωcr to be introduced into the formula is a constant nearly equal to the specific wave amplitude of wrinkles which arise locally in the flange. To predict the critical blank-holding pressure necessary for obtaining a product in which"trace of wrinkles"remains or"no wrinkles"remain, a multiplier ωB or ωA should be applied to the formula instead of ωcr.
TL;DR: In this article, the analysis of vibration of the contracted test piece at resonance conditon is developed and the result is confirmed with experiments, and the stress estimation can be done without the graphical complexity, if an oscillatory amplitude at the top of the test piece is measured.
Abstract: In the ultrasonic fatigue machine previously reported, it was necessary to adopt the test pieces contracted in the mid portion in order to induce the higher stress there, and a graphical method was required for the estimation of the value of the stress induced. In this paper, the analysis of vibration of the contracted test piece at resonance conditon is developed and the result is confirmed with experiments. By this, the stress estimation can be done without the graphical complexity, if an oscillatory amplitude at the top of the test piece is measured. As an application of this analysis, S-N characteristics for bearing steel and copper are obtained.