The research of laminar jet in compressible fluids was dealt theoretically by Pai, Krzywoblocki, Illingworth etc., but they did not obtain analytical solution. Recently, Toose used the Karman-Tsien transformation in boundary layer flow theory and obtained analytical solution under some allowable assumptions, but t seems that his analytical method is difficult to be applied to axialey symmetrical jet, because he uses Karman-Tsien transformation. If we generalize the Bicklly transformation against the jet of the incompressible fluids, we are possible to solve either two dimensional or axially symmetrical jet of the incompressible fluids. In this paper, the author shows the analytical treatment of two dimensional laminar jet.

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Experimental studies on two-dimensional flow through turbine blade cascades lead to the results, which can be summarized as follows : (A) It is found that if the outlet area of blade passage is chosen properly, there is a definite relation between the velocity coefficient and the discharge coefficient, which have been thought conventionaly to be independent of each other. (B) The conventional relation between the kinetic-energy-loss coefficient and the velocity coefficient is corrected. (C) Relations among the discharge coefficient, the velocity cofficient, the kinetic-energy-loss coefficient, the energy-loss coefficient and the total-pressure-loss coefficient is studied. The blade profiles used in these experiments are following three : -a conventional steam turbine blade profile, an aeronautical blade profile, and a thin flat plate. Reynolds' number of the flow is nearly constant, i.e. 2.5×10⁵.

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A rigorous treatment is given of the problem of determining the two-dimensional potential flow of incompressible fluid around arbitrary turbine blades in cascade. The flow problem is resolved by making use of the methods of conformal representation. As in the author's previous paper, the even-numbered blade profiles are transformed into one, the odd-numbered ones into the other of two concentric circles, so that the region about the turbine blades is mapped onto the concentric circular ring region between the two circles. But the process of the transformation is much more simplified and the labour of numerical calculations is considerably reduced.

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Results of the low speed cascade tests on the NACA 6409 section as a compressor blade are presented with the following conclusions : (i) Both stalls on the pressure surface which occurs at a small angle of attack and on the suction surface which occurs at a large angle of attack shift to the larger angles of attack with the decrease in pitch. (ii) Mean total head losses are approximately inversely prortional to pitch and increase with the increase in stagger. (iii) Pressure rise through a cascade increases with increase in turning angle, but saturates to a certain value which depends on stagger, never exceeding 40% of the inlet dynamic pressure. (iv) Experimental turning angles and pressure distributions around a blade agree well with theoretical ones so long as the stagger and the angle of attack are small.

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The characteristics of the Pitot-sphere in the flow with a velocity gradient is different from the standard characteristics in the flow with a uniform velocity distribution. If, therefore, we measure the velocity and pressure of the flow with a velocity gradient with the Pitot-sphere using the standard cheracteristics, the results may contain some errors. To decide the errors, we experimented in the flow in the horizontal pipe approching the Pitot-sphere to the pipe wall. The results of the research may be summerized as follows : (1) The maximum error for the direction of the velocity is ±0.5°. (2) The maximum error for the magnitude of the velocity is ±4% in the range of the flow direction δ=±25°. (3) The maximum error for the pressure is 8% in the range of the flow direction δ=±25°.

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In this paper we investigate theoretically the phenomenon of the pressure transmission of gas through a long pipe. It is necessary for the measurement of the pressure by the manometer to inquire into this problem. Up to the present time the fundamental differential equation has not been solved perfectly. If we assume that the flow in the pipe is laminar and the velocity distribution is same as stationary laminar flow, the solution of the fundamental equation will be obtained.

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Here we take up the case of a fluid contained in an annular region bounded by two concentric or excentric circular cylinders (both of infinite length). When the inner cylinder vibrates, the fluid also vibrates and a vibratory hydrodynamic pressure is set up in the fluid. The Author has made a theoretical calculation about the amplitude of this vibratory pressure, for the following two cases : - (A) Two-dimensional motion, for the case of concentric circular cylinders. The fluid may have a whirling or tangential velocity, together with the vibratory motion. The compressibility of the fluid is taken into account but the viscosity is neglected. (B) Two-dimensional motion, for the case of excentric circular cylinders. The fluid may have a whirling velocity, together with the vibratory motion. The fluid is assumed to be incompressible and non-viscous. In conclusion, it is pointed out that the maximum value of the amplitude of vibratory pressure varies with the square of the frequency of vibration, and that in some cases it can become so great that the phenomenon of cavitation may be caused by it.

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In hydro-electric power station equipped with pressure regulator, if the action of the pressure regulator be ideally perfect, there would be no pressure-rise at all in the penstock. But in actual case, there occurs some amount of pressure rise, even if the pressure regulator is equipped. We may mention, for the causes of this pressure-rise : -(a) The (effective) passage-area of the regulator does not necessarily coincide with the passage area of guide vanes of water turbine. (b) There is a time lag in action of pressure regulator from the time of beginning of guidevane closure. Taking these two factors (a) and (b) into account, the Author has made a theoretical calculation of the pressure rise of this nature, and discussed the effect of these two factors (a) and (b) upon the form of the pressure-time curve. Some comparison with measured curves of actual hydro-electric power plants are also given.

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Following the 1st report, this paper gives the results of experimental research on the leakage of air through straight-through labyrinth packing. especially on the relations between leakage and depth of the pocket. In these results, it was found that the leakage of air was the smallest valve when the pockets were the shallow rectangular grooves. The optimum ratio of its two sides is one to five and always constant when clearance, number of throttlings and pressure ratio are varied. Although decrease of leakage rate is only a few percent, the result is very valuable on the construction of labyrinth packing of straight-through type.

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Saybolt viscometer and Redwood viscometer are used as technical viscometers for petroleum industry in our country. Their jets are specified short tubes having dimensions governed by regulations, so the author calculated Saybolt seconds and Redwood seconds by using the author's experimental results of non-round-edged uniform tubes, short tubes and orifices which had been reported in the 1st and 2nd reports of same subject by putting previous specified dimensions and compared the calculated values with the converted values by using the Ubbelohde's conversion table, and further more by referring to the latest experimental work upon the correction factors of the technical viscometers in Japan, and considered upon the adequacy of the conversion tables and standard instruments.

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With the view of obtaining profoiles to become such straight lines, as test curves of the current meters pass through the origin, the author has made flat plates and circular arc aerofoiles having many kinds of cambers, and tested. When these tests are compared with each other, inverse circular arc aerofoiles is excellent. Results obtained are as follows : I. The starting velocity υ₀ of the current meter increases as the resistance torque increases, and therefore, to make υ₀ smaller the resistance torque of the device must be reduced as far as possible. II. The author has made circular arc aerofoiles having many kinds of cambers, tested, and compared them, and he has made the inverse circular arc aerofoiles, and the test curve of the current meters became a straight line, extension of which nearly passes through the origin.

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In this paper the formulas for calculating the closed quantity, the delivered quantity and their fluctuation of the optional involute gear pump were obtained. And then, the method of designing the involute profile shifted gear which may avoid the evil influence of closing, and its some characteristics were explained. Especially, the author offered that it is desirable for such a gear pump to make the number of gear teeth differed by one tooth.

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In the first and second reports, we described about the classifying characteristics and its analytical method of our new designed classifier by using the cement powder which is passed through the sieve of 200 mesh Tyler Standard Screen as for the four and two classes classification of the particles. But, in order to understand the state of classification of particles in the classifying chamber, it is necessary to investigate the flow patterns of the vortex in chamber. In this report, when the inner and outer pipes of the classifier have a gap or a lap at their both ends and the air stream velocity at the inlet of the classifier is changed at over range of 4.9∼13m/s, we measured the spiral angle, distribution of the static and total pressures, tangential and vertical components of the total velocity of the spiral flow in chamber by a small cylindrical Pitot tube. From the experimental results, we made an analytical and theoretical consideration concerning to the deflection of air flow at the exit of the guide vanes, the distribution of the static pressure difference of the classifier, the relation between the pressure drop through the classifying chamber and air quantity, the relation between the minimum diameter of the classified coarse particles and air stream velocity at the inlet of the classifier.

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By observing the flow characteristics of the turbulent mixing zone and the potential core of jet, we found that the core was not constant as mentioned in Kuethe's theory and had the varying growth range which core part grew to the maximum limit point in ordinary jet speed less than sound one and also the velocity distribution in the flow section was presented as the function with no relation to jet axis x. Besides we examined theoritically and experimentally the variation of turbulent mixing length, flow rate and momentum.

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Measurements of skin frictions and velocity profiles in turbulent boundary layers with adverse pressure gradients are presented. The skin friction was measured by a surface Pitot tube of the stanton type which was calibrated under various pressure gradients. It is said that all velocity distributions near the wall expressed in the universal form u/u^* vs. u^*y/ν are almost the same irrespective of pressure gradient. Our experiments showed that this relationship holds up to a short distance before the separation point. However, near the separation point (H>1.7) the value of coefficient a₁ in the universal velocity distribution u/u^*=a₁+a₂log₁₀ (u^*y/ν) diminished as shown in Fig.12 and the measured values of skin friction were greater than that predicted by the equation of Ludwieg and Tillmann.

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