日本機械学會論文集

既存翼型6個のキャビテーション性能

沼知福三郎, 角田賢治, 千田一郎

1951 年 17 巻 60 号 p. 1-5
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_1

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Three well known profiles of distinguishing form used for blade element, namely Clark Y, Clark Y.H. and R.A.F. 6 have been tested in the cavitation tank of Tohoku University, Sendai Japan, for a study of the effects of form on the cavitation characteristics. The thickness-to-chord ratios of the each profiles are 11 7 and 6 percent respectively, namely 6 profiles have been taken for the test. The aim of the experiment is to provide some data of profiles suitable for blade elements of axial water turbines, pumps and ship propellers. The experimental results have been obtained concerning chiefly to the following items : (1) on the condition of cavitation occurrence, (2) the change of the lift and drag due to the cavitation factor, (3) the polar diagrams at the different degree of cavitation, (4) the comparison of the cavitation characteristics of the three profiles.

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既存翼型の翼列のキャビテーション性能(第1報)

沼知福三郎, 淵沢定敏

1951 年 17 巻 60 号 p. 5-9
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_5

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(1) The characteristics of three kinds of hydrofoils (Clark Y, Clark Y.H. and Ogival form of each 6% thickness ratio) arranged in a straight grate with and without cavitation occurrence have been experimentally obtained. (2) Comparing the three kinds of hydrofoils with each other in view of the lastest cavitation incipience, Clark Y.H. is the most superior. (3) In comparing the characteristics by the polar diagrms, the Ogival 6% is proved to be the most superior at the high speed range of flow. (4) From the standpoint that the angle of incidence, at which the drag-lift ratio is minimum, changes least due to the change of cavitation number, Clark Y.H. is the most superior. (5) The order of superiority mentioned in (2), (3) and (4) coincides with the case of the single hydrofoil free from mutual interference. (6) The hydrofoils in grate present cavitation incipience later than the isolated one. (7) The characteristics of the hydrofoils arranged in this grate condition are superior at low speed but inferior at high speed to those of the single hydrofoil.

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翼列に適する翼型のキャビテーション性能 : 第1報理論第2報による翼型の優秀性能

沼知福三郎, 菊池寿, 横山達郎

1951 年 17 巻 60 号 p. 10-16
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_10

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In order to realize higher power and speed of axial turbines, pumps and ship-propellers, it is necessary, in the design of blade, elements, to get cn hand the hydrofoil-profiles of excellent characteristics. For this purpose, cavitation tests were made on new two profiles obtained by our theoretical method which have been proved to have more excellent characteristics than the profiles hitherto existed. We have named such a profile"Cascade Profile". The method of the experiment is the same stated in our report"Cavitation Tests on Hydrofoils arranged in a Straight Grate". The profiles tested are N.K. 10156 and N.Y. 10156 which were calculated by our method aiming at the lift coefficient to be 0.5 and thickness-chord ratio to be 6 per cent.

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翼列に適する翼型のキャビテーション性能 : 第2報理論第2報補遺による翼型の優秀性能

沼知福三郎, 横山達郎, 村井等

1951 年 17 巻 60 号 p. 17-22
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_17

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In order to obtain new hydrofoil profiles suitable for blade elements of axial flow-turbines, pumps and ship-propellers, namely such profiles which exert excellent characteristics when arranged in a straight grate, in this report cavitation tests have been carried out on two"Cascade profiles"called N.M. 10298 and N.Y. 10198 and Clark Y 8%, both in arrangement of a straight grate. The two cascade profiles had been calculated theoretically by our method aiming at a tolerably high (value of) lift coefficient (C_a=0.9) compared with the thickness-chord ratio (8%). Clark Y 8% have been taken up, for the comparison, because it had been clarified by us to have comparatively low value of drag coefficient at the value 0.9 of lift coefficient in a single condition and also to have good characteristics under cavitation occurence (at cavitation coefficient k_d=0.8-0.4). By the experiment it has been proved that the two cascade profiles are more excellent than Clark Y 8% when arranged in a straight grate from both standpoints of the characteristics (polar diagrams) under cavitation occurence and of late incipience of cavitation.

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翼列に適する翼型の理論的研究 : 第1報翼列をうず列とした取扱

沼知福三郎, 淵沢定敏

1951 年 17 巻 60 号 p. 22-26
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_22

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We are to propose here an idea of profile-form which exerts excellent characteristics when it is used as a blade section in one blade interfered with by the sections in the adjoining blades. That is to say, we are to search for such profile-form which is excellent when it is in a grate, although it might not be so excellent in a single condition. To the inquiry"what property is the excellent profile form to the present time"it must be replied that in the final analysis it is that which has such satisfactory surface pressure distribution as to induce possibly little profile resistance for a given value of lift coefficient. A theoretical method to obtain the profile form of a grate-profile has been given ; therein the adjoining profiles in the profile grate is theoretically replaced by a series of vortices.

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翼列に適する翼型の理論的研究 : 第2報翼列を平板翼列とした取扱

沼知福三郎, 菊池寿

1951 年 17 巻 60 号 p. 26-27
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_26

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We have proposed previously an idea that the profile-form of the blade of an axial flow machinery must be used which exerts a given pressure distribution in a cascade formation, the pressure distribution being one which has been proved to have satisfactory excellent characteristics in a single state. In this report, a method for obtaining such a profile form is stated, in which the effects of the adjoining profiles have been treated as those of the flat plates placed in a straight grate. The result obtained by this method is of the first approximation, but it is proved to be sufficient for practice. At the end, an example of a profile form calculated by our method is given.

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翼列に適する翼型の理論的研究(第2報補遺)

沼知福三郎, 村井等

1951 年 17 巻 60 号 p. 28-30
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_28

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According to our new viewpoint that the pitch-chord ratio and the grate angle of the equivalent grate of the flat plates, which is replaced in the theoretical calculation of the effect to the grate of the required profile-form, should be different from those of the required profile-form, an exact method to determine the values of the pitch-chord ratio and the grate angle of the equivalent grate of the flat plates, has been stated by-way of supplementary note to Report 2. Two numerical examples have been shown for given values of the pitch-chord ratio, the angle of the grate, lift coefficient and thickness ratio. And in one of the examples, the profile-form obtained is compared with that obtained by the method stated in Report 2.

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翼列に適する翼型の理論的研究(第3報)

沼知福三郎, 安陪俊一

1951 年 17 巻 60 号 p. 30-34
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_30

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In our previous papers we proposed to adopt, in the design of the blade of axialflow-turbines, pumps and ship-propellers, such profiles suitable for arrangement in a straight grate, and we stated two methods to find out theoretically the above profiles. In those papers, however, the accuracy of the results was rather unsatisfactory, for the effects of the adjoining profiles were replaced by those of an equivallent street of vortices or a grate of flat plates. In this paper the more accurate method is stated, in which the effects of the adjoining profiles are treated equivallently as those of a grate of Karman-Trefftz profiles, which have the similar profile-form to the required one. Therefore, the theory of a grate composed of the Karman-Trefftz profiles is first stated, then the theoretical method is shown to calculate the above required profiles. Finally, an example of a profile-form calculated by this method is given.

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翼列に適する翼型の理論的研究(第4報)

沼知福三郎, 村井等

1951 年 17 巻 60 号 p. 34-37
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_34

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In this paper, the exact theoretical method to calculate the profile-form has been given, in which the effect of interference on the surface pressure distribution has been analysed based upon the theory on the grate composed of the very profile-forms required instead of the approximate ones introduced in the preceeding reports of the same title. As an example, the profile form-for given values of pitch-chord ratio, angle of the grate, lift coefficient and thickness ratio have been calculated, and then compared with those calculated for the same given values by the methods reported before.

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翼列に適する翼型の理論的研究 : 第5報数値計算が簡易な嚴密解

沼知福三郎, 安陪俊一

1951 年 17 巻 60 号 p. 38-41
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_38

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In our previous papers we proposed to adopt, in the design of the blade of axialflow-turbines, pumps and ship-propellers, such profiles suitable for arrangement in a straight grate. We must admit in Report 1, 2 and 3, however, the accuracy of the results was rather unsatisfactory, because of their approximate treatments ; while in Report 4 the numerical calculation was considerably complicated, although the effects of the adjoining profiles were exactly treated. In this paper, another exact method is stated to calculate the profile-form which has a given surface pressure distribution in a straight grate, and besides the process of calculation is simpler compared with that in Report 4. Finally an example of a profile-form calculated by this method is shown for comparison with the results acquired by the previous methods.

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翼型のキャビテーション性能について

藤本武助, 神元五郎, 山本正

1951 年 17 巻 60 号 p. 41-46
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_41

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To solve two-dimensional flow around an aerofoil, conformal representation which transforms the given aerofoil into a circle, is usually applied. The constants in the mapping function are determined by the profile-form, and in this paper, a method of obtaining these constants from the ordinary camber values at points of 0, 1.25, 2.5, ……, 100% of the chord is explained. From the numerical examples the starting points of cavitation on the surface of aerofoil are determined and compared with experimental results.

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電解槽による翼型の実験

神元五郎, 志水敏詮, 堀岡幸憲

1951 年 17 巻 60 号 p. 47-50
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_47

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It is well known that the equations of two-dimensional potential flow in hydrodynamics have similar forms to them of two-dimensional electric current and that we can solve the hydrodynamical problems by means of electrical measurement of the latter current. In this paper it is shown that a simple"Electrolyte Tank"apparatus is adopted and it gives reliable test results in solving hydrodynamical problems, on a result of measuring flow around a cylinder and aerofoil.

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任意翼型円形翼列の写像について

神元五郎

1951 年 17 巻 60 号 p. 51-58
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_51

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This paper deals with the flow around the circular wing lattice, as example the guide vanes of reaction type water turbines. The circular lattice composed of logarithmic spirals passing through the leading and trailing edges of each aerofoil, as well known in the theory of centrifugal pumps, can be conformally represented into a unit circle. Assuming that the camber line of given aerofoil does not much differ from the above logarithmic spiral and that the thickness is small, the given circular wing lattice also can be conformally represented into a unit circle, adding doublets of higher order at the center of circle, so that it should express the camber and thickness. Then expressing the flow around the circle by the complex function so that it should satisfy the flow around the lattice, the flow around it can be calculated.

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任意翼型直線翼列の写像の一方法

神元五郎

1951 年 17 巻 60 号 p. 58-63
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_58

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In this paper the problem of two-dimensional flow of perfect fluid through the straight wing lattice composed of aerofoils with arbitrary shape is dealt. The method described here is the modified one of Theodorsen-Garrick's method of an isolated aerofoil to the straight wing lattice. Using the mapping function that the wing lattice composed of flat plates can be conformally transformed into a unit circle, the given wing lattice composed of thin aerofoils with small camber can be conformally represented into a nearly circular contour. Then the leading edge of basic wing lattice composed of flat plates should be chosen at the middle point between the leading edge of given aerofoil and the center of curvature at the point. Moreover, the contour can be represented into a circle by means of Theodorsen-Garrick's mapping function. So determining the complex function around the circle, the hydrodynamical properties of wing lattice can be calculated.

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与えられた表面圧力分布を有する翼型を求める一方法

菊池寿

1951 年 17 巻 60 号 p. 63-67
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_63

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A method for obtaining the profile-form which has the given surface pressure distribution is stated. The method is based on a theorem about the velocity along a profile and enables us to obtain separately the thickness distribution as well as the mean camber line of the required profile by simple calculations. Therefore, we can easily understand the relation between the pressure distribution and the profile form. Calculation has been made for a Joukowski profile which has the thickness of 11 percent and the camber of 2.5 percent of chord and Munk 6 profile. It showed that the deviation of the calculated form from the exact one was very small, which proves that the present method is very satisfactory for practical use in respect to the facility of calculation and to the accuracy of result.

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キャビテーションに関する一実験

鬼頭史城

1951 年 17 巻 60 号 p. 67-69
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_67

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The Authour has constructed a small cavitation tank, the water passage having rectangular section 200 mm×40 mm. First, pressure distribution curve along the back surface of a blade section was obtained, the chord length of the blade being 100 mm. Secondly, using several circular bars of dia. 12 mm, to 2 mm, the length l of cavity appearing behind the bar was measured and plotted into curves with cavitation number k as abscissa and its was found that for small values of k (k<0.6), the curves did not converge into a single curve. This fact seems to show that the cavitation number k is not the only practical factor that governs the actual cavitation phenomena.

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与えられた圧力分布を持つ翼型の簡易計算法

藤本武助

1951 年 17 巻 60 号 p. 69-73
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_69

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This paper deals with the problem of constructing the form of airfoil section which has given pressure distribution. The effects of angle of incidence, mean camber and thickness upon the velocity on the surface of airfoil are approximately independent of each other. This fact is utilized and from the difference of velocities on the upper and lower surfaces of the airfoil, the mean camber line and the angle of incidence are determined, while from the mean velocity, the thickness is determined. Although the labour of calculation is little, yet the result is very satisfactory. The above-mentioned method is extended to the case of wing lattice and procedure of calculation is explained.

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平板翼列の風速分布 : 軸流回転機の研究第7報

大塚新太郎

1951 年 17 巻 60 号 p. 73-78
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_73

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The writer has calculated Air speed distribution of flat plate infinite multiplane by means of conformal transformation method. It is thought that the obtained values themselves are not important, but the qualitative tendency of derived curves is useful for the study of infinite multiplane. This report is one of"Study of Axial Flow Machine Series". They were published on the"Journal of the Aeronautical Institute of Tokyo Imperial University"and the"Report of the Institute of Science and Technology of University of Tokyo".

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圧縮性流体中の二次元翼列

岡崎卓郎

1951 年 17 巻 60 号 p. 78-81
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_78

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Prandtl-Glauert's method of small perturbation is applied to the flow past wing lattice, and the correction method for the zero lift angle and the lift coefficient is abtained.

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水車の導羽根に関する理論

沼知福三郎, 岡田克人

1951 年 17 巻 60 号 p. 81-86
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_81

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The flow through the guide vanes is studied theoretically on the assumption of its being potential flow through a circular lattice composed of hydrofoils. By this theory the characteristics of guide vanes of a given water turbine can be analytically clarified, and inversely the suitable form of guide vanes can be obtained when the quantity of flow and other elements of driven condition are given. The method of analysis is made by conformal translation and the circular lattice is converted to the straight one, on which the theoretical analysis has been fully studied by the staff of our institute and is able to be utilized for the present analysis on the circular lattice. As numerical examples, the pressure distribution calculated by our method about the two kinds of given guide vanes has been proved to have a satisfactory agreement with the result experimentally obtained by one of the present writers (F. Numachi).

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風車翼の初期計画資料

塚原鶴夫

1951 年 17 巻 60 号 p. 86-89
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_86

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Glauert gave a design formula and some performance of such an optimum-windmill, which can obtain the maximum power from the ideal fluid. However, the real wind is viscous. Therefore, the influence of viscosity should be introduced into the analysis. Now, aerodynamically the optimum-windmill's performance depends upon the speed ratio, Reynolds Number, blade section shape, and surface roughness. Among these factors, the author introduced the speed ratio and the section lift by drag ratio, which is the function of the last two factors and should be referred to the Reynolds Number, into the Energy-Momentum theory. Under the above treatment he obtained the quantitatively practical design data of the optimum-windmills, suitable for the real wind, as the function of the speed ratio, inducing the section L/D as the parameter.

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翼車附近の流動について(第1報)

田伏敬三

1951 年 17 巻 60 号 p. 89-92
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_89

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In this report, which was read at the Tokyo Meeting May 1944, the author emphasizes the use of the irratational condition to obtain the stream lines on the meridian section of runners (C_m lines). In curvilinear rectangular co-ordinates, the irratational condition gives : 2ε_m=∂(rc_θ)/r∂n=0 (a) 2ε_n=∂c_m/(r∂θ)-1/r ∂(rc_θ)/(∂m)=0 (b) 2ε_θ=±c_m/l-∂c_m/(∂n)=0 (c) where c=absolute velocity, ε=vorticity, r=radial distance, l=rad. of curveture of c_m line, m=direction of c_m line, n=normal to c_m line, θ=direction of runner rotation, suffixes m, n, θ mean m, n, θ components. c_m lines can be drawn from (a) (c) and these lines deatermine the distribution of velocity, dead water spaces etc., which are of great imporatance in desgning runners and presuming characteristics of hydraulic machines. The author gives also some examples and fundamental relations on potential flow with c_θ.

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境界層の近似計算法

藤本武助

1951 年 17 巻 60 号 p. 93-96
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_93

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To improve Pohlhausen's method of approximate solution of the laminar boundary layer problem, the velocity distribution in the boundary layer is expressed as follows : u/(u₀)=F(y/δ)+λ'/αG(αy/δ). And the separation point is determined applying the results of exact solutions by Howarth and Tani in the case of flow u₀=U₁-U_nxⁿ. The separation of turbulent boundary layer was, hitherto, estimated by Buri's parameter [numerical formula]. The relation between T and u₀u₀''/u₀'² at the separation point which is obtained by experiment is also shown in the paper.

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後流の拡散について

藤本武助

1951 年 17 巻 60 号 p. 96-98
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_96

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The wake behind a body placed in a flow with velocity gradient in the direction of flow is investigated theoretically and compared with the result of experiment. In the case of two-dimensional flow with weak velocity gradient, the velocity distribution in the wake is same as the case of uniform flow, and the momentum thickness and the breadth of the wake calculated by the momentum equation coincide with experimental result.

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粘性流体の一基礎式について

伊藤英覺

1951 年 17 巻 60 号 p. 99-102
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_99

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In this paper it was shown that the equation δ∫∫∫Φd×dxdydz=0, which expresses that the dissipation of energy is minimum, is equivalent to Navier-Stokes'equation, if inertia terms are zero and external forces are derived from a potential. Therefore, if fluid flows under the above condition, we can determine the motion by assuming a suitable velocity distribution and deciding its unknown constants so that they satisfy the above equation. By this method, the flow through a straight pipe with isosceles triangle cross-section was solved. The method was also applied to the flow around a sphere, and Stokes'solution was obtained. Each of these examples shows that this energy method is applicable to those problems with success.

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拡大および收縮円すい管内の粘性流

伊藤英覺

1951 年 17 巻 60 号 p. 103-108
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_103

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Laminar flows in convergent or divergent pipes were treated. To find the approximate solution, it is assumed that the streamfunction ψ can be expanded in the form [numerical formula] being the function of θ alone. In this paper ψ_t's were solved taking into account to the order of ψ₂, and the velocity components V_r, V_θ and the pressure distribution in the pipe were found. When the angle of the vertex of the cone is large, it wiss assumed that the boundary layer grows along the wall of the cone. For the convergent flow, the boundary layer equation have been solved and the local frictional coefficient and the velocity distribution in the boundary layer have been found.

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回転円板の乱流遷移に関する研究

渋谷巖

1951 年 17 巻 60 号 p. 109-114
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_109

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The turbulent transition of a flow between two parallel walls and rotating circular disc was investigated theoretically. Since the distances between them are assumed to be very small, the viscosity of a fluid may be effective all over the space, and two components of the disturbing velocity seems to be very important to cause the transition in a flow and to be able to neglect the other component normal to the disc. A momentum equation can be introduced by integrating the equation of motion with respect to z, which is taken in the direction normal to the disc surface, from the disc to the wall. In this case two types of velocity distribution can be considered and the critical values of Reynolds number corresponding to each case were found. The experimental points obtained by Schultz-Grunow and Y. Kitani are found between these two theoretical ones.

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垂直円管に沿う自由流れの乱流遷移について

渋谷巖

1951 年 17 巻 60 号 p. 114-119
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_114

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The instability of a free flow along a vertically supported circular pipe has been found by some investigators already, but its mechanism has not been clarified as yet. Therefore, in this paper the properties of such unstable flow were investigated theoretically on the assumption of the so-called small vibration theory. We assumed the thickness of a flow membrane is very small, i.c. h=0.6∼1.0 mm, and the type of a flow is axiallical symmetrical, then the disturbance may be assumed to be two-dimensional. We also assumed a disturbance is composed of two different types of velocity, namely one is cosine typed and the other is hyperbolic cosine typed. The former may vanish on the wall and also on the free surface, but the latter may be very large on the free surface, so that the waving flow observed at the upper surface of the flow may be raised by the latter component.

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粘性流体による密封作用に関する研究 : 第1報ねじ型粘性ポンプのポンプ性能

浅沼強

1951 年 17 巻 60 号 p. 119-125
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_119

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For the purpose of obtaining a sealing method of rotary shaft penetrated into a vacuum or high pressure vessel, the author proposes to prevent the leakage by viscous fluid which has a very high pressure due to the pumping-action of the rotary shaft with a helical screw groove. In this paper he studies theoretically the pump-performances under the laminar theory and it is cleared that to obtain the maximum pump efficiency, some dimensions of the screw groove are to be selected as follows : a) the width of the thread to be as narrow as possible. b) the ratio of width to depth of the groove to be equal 5∼10 : 1. c) the ratio of gap to depth of the groove to be 0.1∼0.2 : 1. d) the helical angle of the screw thread to be about 10∼20 degree.

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粘性流体による密封作用に関する研究 : 第2報, ねじ型粘性ポンプの密封性能

浅沼強

1951 年 17 巻 60 号 p. 126-130
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_126

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In this paper the author studies the sealing-performances of the screw-type viscous pump using it as a sealing axpparatus, and examines theoretically the effects of each dimension of the screw groove for the pump lift. It is shown that in order to obtain maximum lift, the dimensions of the pump must satisfy certain conditions as follows : a) the axial length, radius and angular velocity of the rotor and the kinematic viscosity of the sealing fluid are proportional to the lift respectively. b) the lift is inversely proportional with square of the clearance gap. c) the width of the groove to be equal to the width of the thread. d) the ratio of width to depth of the groove to be 5∼20 : 1. e) the ratio of the gap to the depth to be about 0.2 : 1. f) the helical angle to be about 10∼11 degree.

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直管および曲管内の層流理論(第1報)

伊藤英覺

1951 年 17 巻 60 号 p. 130-133
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_130

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In the previous paper the writer explained that when it was difficult to solve Navier-Stokes'equation directly, it was convenient to find the solution from the standpoint of minimum energy dissipation if inertia terms in the equation could be neglected. In this paper laminar flows, through straight or curved pipes with various cross-sections, were solved from this standpoint and in each case the pressure drop, velocity distribution and discharge per unit time were obtained. As to the problems of which solutions had already been found, such as the flow through a straight pipe of rectangular cross-section, it was shown that by this energy method they are solved with more easiness than by other methods.

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直管および曲管内の層流理論(第2報)

伊藤英覺

1951 年 17 巻 60 号 p. 133-140
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_133

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The author gives a theoretical investigation to laminar flows which run through curved pipes of elliptic and rectangular cross-sections whose axes are curved in circular forms. In each case, equations of motion were solved by the method of successive approximation, and the behavior of the fluid flowing through curved pipes was clarified numerically.

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移動壁をもつた平行すきま内の流動について

浅沼強

1951 年 17 巻 60 号 p. 140-146
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_140

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The author deduces some theoretical formulae for the turbulent flow through a fine clearance space (δ) between two parallel walls, one of them being in relative motion to the other at arbitrary angle to the direction of the pressure gradient. Therefore, he applies this formula to the flow through the annular space formed by two concentric pipes in relative rotation, and then obtains an empirical formula for the turbulent flow in such a case using the experimental data of R. J. Cornish. In case of the flow through the concentric double pipes in relative rotation, if we consider the Reynolds number as an important criterion of the state of flow, it is reasonable to adapt [numerical formula] instead of usual [numerical formula], where v is kinematic viscosity, w and v is resultant and axial mean velocity respectively.

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分岐および合流管の水頭損失に対する考察

沖巖, 川口毅

1951 年 17 巻 60 号 p. 146-151
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_146

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We have, in the hydraulic laboratory of Waseda University, determined the coefficients of loss of head due to separation of one stream into two with Right-angled branch pipes, the main being 38.2 mm in diameter, and the branches of three kinds, respectively 38.2, 25.8 and 13.2 mm in diameters. The results have been compared with those obtained by Vogel and Kinne. Next we have performed experiments on a 7.9/7.9 right-angled branch pipes when two streams combine into one and compared the results with those obtained by Kasai and by Vogel and Kinne. After making invetingations a lot of important explanations has been done about the coefficients thus obtained.

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流体の非定常流に対する解法とその吸入効率計算に対する応用

村上健吉

1951 年 17 巻 60 号 p. 152-157
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_152

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A very effective equation that can be applied to many problems concerned with variable pipe line, is obtained by integrating one dimensional Euler's equation remaining its non-stationary term. Thus, we get an equation as follows : dq/(dt)+q²/(2Φ²)+p₁/p-H₀=0 In this paper, I am showing an instance in which this equation is proved to be useful in dissolving the charging efficiency of internal combustion engines. This problem has been analysed by the method of wave equation, where gas in a suction pipe was considered as wave medium. Whereas, it is regarded, in this case, as a uniform mass. Consequently, the charging efficiency is expressed by the average value of suction state. This method of handling the problem is quite effective when multiple cylinder engine is used, and the fluctuation of suction pressure is less important than the average value of it.

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円管内の層流熱輸送に及ぼす粘性の変化の影響について

毛利浩

1951 年 17 巻 60 号 p. 158-162
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_158

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On the problem of the heat transfer to a fluid flowing with the laminar velocity distribution through a circular pipe, at a section of which the surface temperature changes discontinuously from T₀ to T₁, the effects of the variation of the viscosity due to the temperature t are treated. It is assumed approximately μ=1/(A+Bt), and the temperature distribution on which the viscosity of the fluid depends is taken the average in an direction of the axis, and put approximately. t=T₀+(T₁-T₀) r²/a² The dissipation terms are neglected and the thermal constants except the viscosity are assumed to be independent of the temperature. Under these assumptions the equation for the temperature is solved. sa a supplemet it is shown that the effect of the natural convection to the heat transfer in the vertical pipe is calculated in the same manner.

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歯車ポンプにおける漏れ(第1報)

板谷松樹, 市川常男

1951 年 17 巻 60 号 p. 162-167
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_162

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The authors calculated quantities of leakage q₁ and q₂ through the side clearances S between the casing and gear bodies, and between the casing, and gear teeth and q₃ through the tip clearances δ between the casing ane teeth separately. Fig. 7 and Fig. 8 show the comparison of above results with the experimental results by F. Ascher and L. Mattheus.

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圧力分布を与えて直線翼列翼型を求める一方法

藤本武助, 神元五郎, 廣瀬幸治

1951 年 17 巻 60 号 p. 168-170
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_168

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Applying the thin aerofoil theory of straight wing lattice which is already published in this Transaction, Vol. 14, No. 47, 1948, a method of calculating aerofoil form is obtained. The aerofoils of the wing lattice are transformed into a unit circle by conformal representation and from the velocity on this unit circle which corresponds to the given pressure distribution, the form of the aerofoil is determined.

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滴れの研究 : 第3報水滴と気ほうについて

高玉績

1951 年 17 巻 60 号 p. 170-176
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_170

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In this paper, it was proved theoretically that the steam bubble to be formed on the horizontal heating surface satisfies the equilibrium equation of the water drop attached at the under side of horizontal plate, and that the steam bubble at the under side of heating surface satisfies the equation of the water drop on the horizontal plate. Therefore, in the both cases of them, the physical properties introduced from the equation may be said to be common together. The maximum diameter D_max of steam bubble at the point of seperating from the heating surface is given by [numerical formula] in which T is the surface tension in dyne/cm, ρ the density of water in gr/cm³ and g the acceleration of gravity in cm/sec².

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「管内流における伝達エネルギと消散エネルギとの分布について」と関連して

宮津純

1951 年 17 巻 60 号 p. 177-178
発行日: 1951/10/20
公開日: 2008/03/28

DOIhttps://doi.org/10.1299/kikai1938.17.60_177

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The contents of the paper by the author quoted in the subject were compared with those of the paper"The mechanism of energy loss in fluid friction"by B.A. Bakhmeteff and William Allan.

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