Journal of Zosen Kiokai

On the theory of wave resistance of a body gliding on the surface of water

H. Maruo

1949 Volume 1949 Issue 81 Pages 1-15
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.1

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The writer previously researched the pressure resistance of a plate gliding on the surface of water in the two-dimensional case, and it was found that the pressure resistance consists of sprash resistance and wave resistance.
The sprash resistance has the same properties in the three-dimensional case as in the two-dimensional one, but the wave resistance is different in each other, and though the two-dimensional motion is comparatively simple, the three-dimensional motion has very complex features.
The present investigation shows that the fluid motion near the gliding body bears a great resemblance to the vortex motion occuring behind a wing when the speed of the gliding body is sufficiently large, so wave resistance has the same properties as that of induced resistance of the wing. The writer has also found an approximate formula by which the shape of gliding surface for a given pressure distribution can easily be calculated when its aspect ratio is considerably large. The shape of the gliding surface that gives the minimum wave resistance was calculated and such a conclusion has been obtained that for large Froude numbers the minimum wave resistance is given by the pressure surface whose inclination to the horizontal plane has a lateral distribution of nearly elliptic type.

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A Consideration on the Design of Screw Propellers of Tug Boats and Trawlers

Masao Kinoshita, Yasufumi Yamanouchi

1949 Volume 1949 Issue 81 Pages 17-45
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.17

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Tug boats and trawlers have their screw propellers operated in two different conditions, i. e. voyaging free and towing other vessels or trawling nets in fishing. Therefore, for instance, a propeller designed as the most suitable for free voyages is not always so efficient as can utilize the power from the engine fully enough in towing conditions. Requirements in those two cases are inconsistent with one another, so it is theoretically impossible to design a propeller that fulfils both requirements simultaneously, as long as a castant pitch propeller is used.
Therefore a variable pitch propeller will be taken into consideration. But it is not so widely used for its complex mechanism, high price and lack of responsibility.
In this paper, The authors intended to establish a method of designing propellers that are most effic-ient synthetically in both conditions voyaging free and towing, when an engine was given and constsnt pitch must be used.They applied this method to the case of a tug boat belonging to the Ministry of Transportation “Dai-ku Tetsuei-maru” and compared its results with those of towing and speed trial tests by the actual ship. They believe this method can be also applied to the design of propellers of fishing boats, such as trawlers or small trawlers, that is a question to be solved in our country now.

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On the Characteristics of Propellers in Non-homogeneous Flow

T. Taniguchi

1949 Volume 1949 Issue 81 Pages 47-95
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.81_47

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The characteristics of marine propellers are usually discussed under the assumption that the flow is uniform and parallel to the propeller axis. But the actual velocity field in which a propeller is working, has neither the same direction as the propeller axis, nor the homogeneous distribution of velocities on the disc area. And the effect of these asymmetry or non-homogeneity are occasionally in question. Of these, the effects of oblique flow have been investigated considerably, but the effects of non-homogeneous flow have not been discussed. The author, calculating the characteristics of blade elements in a non-homogeneous flow and integrating these over the whole propeller under the reasonable assumptions, has gained the theoretical formulas on the characteristics of propeller in non-homogeneous flow. The coefficients of forces and moments are numerically calculated using the open-characteristics of series-model propellers and represented graphycally.

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“One Note on the Free Rolling Period of a Model Ship”

Keizo Ueno

1949 Volume 1949 Issue 81 Pages 61-70
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.61

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In this paper the author theoretically analysed the effect of the surface tension of the surrounding water upon the free rolling period of a model ship and compared with the free rolling experimental results, and he found that the free rolling period decreases in accordance with the decrease of the amplitude when the amplitude is very small, and also that this phenomenon arises in the free rolling of a model ship, but not in that of an actual ship.

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A Theoretical Study on the Buckling of Plates Compressed beyond Proportional Limit

M. Watanabe

1949 Volume 1949 Issue 81 Pages 71-84
Published: 1949
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.81_71

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In this paper the Author gives a result of theoretical study, made by him, on the plastic buckling of plates. In the first, the general theories are shown from his fundamental theory of plasticity and in the later part, the critical loads of simply supported rectangular plates compressed beyond elastic limit in one direction are obtained theoretically and experimentally.
These results show that the authors theories are in agreement with the experiments.

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On the Elastic Instability of Orthogonal Anisotropic Cylindrical Shells, especially the Buckling Load due to Compression, Bending and Torsion

Tsuyoshi Hayashi

1949 Volume 1949 Issue 81 Pages 85-98
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.85

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This problem has been studied by several authors, but as the formula for the buckling load it is merely derived the determinantal equation of conditions of buckling, and as the orthogonal anisotropy in its analysis it is contained only the differences of dimensions of outer skin in two perpendicular directions.
It is an urgent need in practice, to derive the explicit expression for the buckling load of orthogonal anisotropic shells, containing the general elastic constants, rigidities and dimensions. From this point of view, the author derived in general form the equation (21) (36) (37), and (57) (58) for compression-, bending- and torsion-buckling. Excepting the case of equation (21), these equations give a pretty good agreement with the experiments.

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Stifled Plates under the Plane Force and Surface Pressure

Tsuyoshi Hayashi

1949 Volume 1949 Issue 81 Pages 99-111
Published: 1949
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.81_99

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The author analyed the deflection and the stress distribution of general rectangular plates under the plane force and surface pressure and obtained the practical method of strength calculation for these plates, and compared his results with the experiments in which the clamped square plate was used, and found the satisfactory agreement with theory and experiments. (Fig. 6 & 7.)

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[title in Japanese]

[in Japanese]

1949 Volume 1949 Issue 81 Pages 113-127
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.113

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On the Calculation of the Transverse Strength of Ships by the Relaxation Method

K. Terazawa, J. Yagi

1949 Volume 1949 Issue 81 Pages 129-144
Published: 1949
Released on J-STAGE: September 03, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1949.129

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The formulae of influence coefficients for the curved members which are connected stiffly to the structures were derived in this paper. By the aid of these formulae, influence coefficients of the members of the transverse structures of ships can be calculated, and these values are used to the calculation of the transverse strength of a ship, in which the calculations are preformed by the R. V. Southwell's Relaxation Method. By the Relaxation Method, we can get the bending moments acting on the transverse structures of ships, which have two or more decks, more easily than thecalculation by the orthodox method (i. e. the principle of the least work), and the deformations can be also obtained at the same time. Hence the strength and the rigidity of the transverse structure can be known at the same time, by this method.
As an example of application, the cargo ship “Okinoyama Maru” was treated, and it was confirmed that the bending moments calculated by the above method consist with them by the orthodox method. By the way, the effects of the camber of the deck beam, bridge deck and skeleton floors on the strength and rigidity of the transverse structure were investigated on the same ship.

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