| タイトル | Effect of mean-velocity profile shapes on sound transmission through two-dimensional ducts |
| 著者（英） | Hayfeh, A. H.; Shaker, B. S.; Kaiser, J. E. |
| 発行日 | 1974-06-08 |
| 言語 | eng |
| 内容記述 | Acoustic propagation through a lined two-dimensional duct is examined in order to assess the influence of the shape of the mean-velocity profile on the attenuation rate. Five mean-velocity profiles are considered: linear, parabolic, Pohlhausen, 1/7th power law with a linear sub-layer, and linear with slip at the wall. It is shown that when the attenuation rate is tabulated as a function of the boundary-layer thickness, as is usually done, substantially different results are obtained from the several mean profiles. However, when the displacement thickness is used, a considerable collapse is achieved in the attenuation curves that are obtained from the various profiles. For downstream propagation, all profiles produce essentially the same results over a reasonable range of boundary-layer thickness. However, for many cases of upstream propagation, the results from the 'turbulent' boundary-layer profiles differ significantly from the results of the other profiles even when compared on the basis of displacement thickness. |
| NASA分類 | FLUID MECHANICS |
| レポートNO | 74A35021 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/452137 |
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