| タイトル | Effect of Nose Bluntness on Transition for a Cone and a Hollow Cylinder at Mach Numbers 1.41 and 2.01 |
| 著者（英） | Monta, William J.; Czarnecki, K. R.; Howard, Paul W. |
| 著者所属（英） | NASA Langley Research Center |
| 発行日 | 1961-04-01 |
| 言語 | eng |
| 内容記述 | An investigation has been made to determine the effects of nose bluntness on boundary-layer transition for a cone with an included angle of 10 degrees and for a hollow cylinder. The tests were conducted at Mach numbers of 1.41 and 2.01 for free-stream Reynolds numbers per foot ranging from 1 x 10(exp 6) to 9 x 10(exp 6). The investigation was made with the use of schlieren photography for which the models were aligned with the free stream. For the 10 degree cone, the favorable effects of nose blunting were so small at both test Mach numbers as to be lost within the experimental accuracy. For small amounts of nose blunting on the hollow cylinder, for which the ratio of bluntness height to transition distance for the sharp-leading-edge cylinder was relatively small, there was little, if any, effect of blunting on transition. For somewhat larger values of this ratio, nose blunting had a favorable effect on transition. The magnitude of the favorable effect was dependent upon the size and the shape of the bluntness, and the maximum increase in transition distance relative to the sharp-leading-edge cylinder is in good agreement with the theoretical predictions of NACA Technical Report 1312. For relatively large values of the ratio of nose bluntness to transition distance, the effects of nose blunting were adverse for both the cone and the cylinder. In general, adverse effects due to blunting were larger for the flat bluntness than for the hemispherical or the round bluntness of equal bluntness height. Increasing the Mach number increased the size of bluntness required to induce adverse effects at constant free-stream Reynolds number per foot, delayed the adverse effects to higher values of Reynolds number per foot for constant nose bluntness, and reduced the abruptness of the transition decrease. |
| NASA分類 | Aircraft Design, Testing and Performance |
| レポートNO | NASA-TN-D-717
L-762 |
| 権利 | No Copyright |
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