著者

TOMOTIKA Susumu

出版者

東京帝國大學航空研究所

雑誌

東京帝國大學航空研究所報告 = Report of Aeronautical Research Institute, Tokyo Imperial University

巻号頁・発行日

vol.7, no.94, pp.357-393, 1933-03

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§12. In the present paper, we have calculated again, by using the well-known BLASIUS' formula, the moment M of the force acting on a flat plate about its mid-point, which is placed obliquely in a steady irrotational continuous flow of an incompressible perfect fluid bounded by two parallel plane walls, under the supposition that the mid-point of the plate lies on the central line of the channel. The method of analysis used in this paper was slightly different from that employed in my previous paper, but the result obtained was, of course, the same. Considering only the practically important cases in which the ratio of the breadth 2α of the plate to the width D of the channel is fairly smaller than unity, we have arrived at the result that there is always an increase of the moment of the force due to the presence of the channel walls. Approximate expressions for the moment have been given as power series of 2α/D, retaining however only the first two or three important terms. Numerical calculations of the values of M/M_0 have been carried out for the case in which β is equal to 45°, where M_0 is the moment of the force acting on a flat plate with the same breadth 2α placed in an unlimited stream, and the approximate curve for M/M_0 was drawn against the ratio 2α/D. Then, basing upon our results, we have anticipated the tendency of variation of the moment of the force exerting on a RAYLEIGH disc with the ratio of its diameter to that of a tube, in which the disc is suspended obliquely in such a way that its angle of attack is equal to 45°. Lastly, as an addendum, approximate curves for M/M_0 drawn against 2α/D were shown for the cases in which β is equal to 10°, 20°, 30°, 45°and 60°respectively.