Studies on the Subsonic Flow of a Compressible Fluid past an Elliptic Cylinder

• 友近, 晋

• 玉田, 珖

• TOMOTIKA, Susumu

• TAMADA, Ko

書誌事項

タイトル別名

• 楕圓柱の周りの壓縮性流體の流れに關する研究

抄録

§17. In the present paper, the two-dimensional irrotational subsonic flow of a compressible fluid past an elliptic cylinder placed at an arbitrary inclination to the direction of the undisturbed stream has been re-investigated, with a special intention of studying the manner in which the value of the so-called critical MACH number for the elliptic cylinder varies with the angle of attack as well as with the thickness ratio of the ellipse. The critical MACH number is, as is well known, the value of the MACH number at which the local speed of sound is first attained in the field of flow, and according to the results of recent experimental investigations, it has a close connection with an important phenomenon called the compressibility burble. We have employed the method of POGGI, as in KAPLAN's papers. Although KAPLAN has confined his attention chiefly to the state of affairs on the surface of the elliptic cylinder, yet we have generalised the analysis to some extent, by obtaining first the velocity potential at any point in the field of flow and then proceeding to the discussion of the state of affairs on the surface of the body. Very laborious numerical calculations have been carried out in detail and thus the values of the critical MACH number M_crit have been found as functions of both the angle of attack and the thickness ratio of the ellipse. The results are shown graphically in Figs. 2, 3 and 4, where the ordinate gives the values of M_crit and the abscissa gives the thickness ratio t of the ellipse. One of the interesting results obtained is that when the angle of attack takes any value different from 0°and 90°, the curve of the critical MACH number plotted against the thickness ratio t has a maximum at a certain definite value of t. This point seems to be worthy of special notice. Also, we have calculated the moment of the fluid pressures acting on the surface of the elliptic cylinder with respect to the centre of the ellipse, and performing various numerical calculations we have discussed the effect of compressibility upon the moment of the elliptic cylinder. It is found that when the value of the angle of attack is fixed, the value of the ratio M_c/M_i for a definite elliptic cylinder increases as the MACH number increases and also that the value of M_c/M_i for a definite MACH number increases slightly as the angle of attack increases, where M_c denotes the moment which an elliptic cylinder experiences when placed in the compressible fluid flow and M_i the moment which the same elliptic cylinder experiences when placed, at the same angle of attack, in the incompressible fluid flow. Further, the validity of GLAUERT-PRANDTL's approximate formula for the ratio M_c/M_i has been discussed briefly.

資料番号: SA4146982000

収録刊行物

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

  東京帝國大學航空研究所報告 = Report of Aeronautical Research Institute, Tokyo Imperial University 15 (201), 477-551, 1940-11

  東京帝國大學航空研究所

詳細情報

• CRID: 1050285299939646336
• NII論文ID: 110004557416
• NII書誌ID: AA00387631
• Web Site: http://id.nii.ac.jp/1696/00035436/
• 本文言語コード: en
• 資料種別: departmental bulletin paper
• データソース種別:
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  • CiNii Articles