| タイトル | Acoustic results of supersonic tip speed fan blade modification |
| 本文（外部サイト） | http://hdl.handle.net/2060/19740021271 |
| 著者（英） | Jutras, R. R.; Kazin, S. B. |
| 著者所属（英） | General Electric Co. |
| 発行日 | 1974-01-01 |
| 言語 | eng |
| 内容記述 | A supersonic tip speed single stage fan was modified with the intent of reducing multiple pure tone (MPT) or buzz saw noise. There were three modifications to the blades from the original design. The modifications to the blade resulted in an increase in cascade throat area causing the shock to start at a lower corrected fan speed. The acoustic results without acoustically absorbing liners showed substantial reduction in multiple pure tone levels. However, an increase in the blade passing frequency noise at takeoff fan speed accompanied the MPT reduction. The net result however, was a reduction in the maximum 1000-foot (304.8 m) altitude level flyover PNL. For the case with acoustic treatment in the inlet outer wall, the takeoff noise increased relative to an acoustically treated baseline. This was largely due to the increased blade passing frequency noise which was not effectively reduced by the liner. |
| NASA分類 | AIRCRAFT |
| レポートNO | 74N29384
R73AEG07
NASA-CR-121233 |
| 権利 | No Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/193727 |
