Journal of the Society of Mechanical Engineers

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In the present paper the author treats the potential flows of the sink and source lying on the straight boundaries of the field in a half strip form. Seven flow mode in three cases of the distribution of the sink and source are discussed. As an extension of one of the flow modes a vortex is superposed on a source situated at a point in the limited field. Thus, the author studies, as an example of the above flow, the manner of motion of water with a whirling in the draft tube pit of a water trubine. The distributions of velocity and pressure, the profiles of free surfaces and the position of stagnation are determined. The results of calculations agree well with those of gentle flow in the experiments with a model pit and draft tube carried out by the author in the Hydraulic laboratory of Waseda University and the experiments show that the characteristics yet remain even in the agitational flow. The stagnation point correspond to the position at which the free surface takes maximum height, and its position on the boundary suggests the strength of a whirling effort. At a point of draft tube outlet the free surface attains a considerably low level which may be accounted for one of the causes of the vibration of a draft tube.

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Recently the Government Railways made new type 13 tons capacity refrigerator cars improving the fundamental parts such as body structures insulations and ice tanks. The construction of this new type car is of the steel body framing on the steel underframe. The insulation is consisted of cork plates which are wrapped up with waterproofing paper. The airspaces between the layers of insulating materials are eliminated. The outside of the car body is covered with wooden sheathing while the inside is covered with sheet iron and made water tight so as the insulation is effectually protected. Four overhead ice tanks, total capacity 2・5 tons, made of sheetiron are placed just below the roof. With this new type refrigerator car our principal expectations were the decreased ice consumption and uniform interior temperature. These expectations were verified by the comparative test trip conducted in last Augast, of this is new type car and the old type car equipped with end bunkers. In this paper the result of this test trip as well as the performance of this new type cars are described.

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The "Independence of National Defence" depends on the "Developement of General Industry". and the "Scientific War of to-day" requires the "Up to date Men of War" built entirely by Home industry. The principal object of this paper is to give informations concerning the mutual relation of Naval and General industry in Japan. A further object is to explain some requirements, from a naval constructor's Standpoint, to the members of the "Kikai Gakkai", the leaders of our general industry. The final chapter gives a conclusion that the admirable situation of our naval forces is the result of familiar cooperations of the engineers in your positions and our's; yet the Navy expects more intimate deliberations with you to complete desirable developement in the mearest future.

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