| タイトル | Noise reduction evaluation of grids in a supersonic air stream with application to Space Shuttle |
| 本文（外部サイト） | http://hdl.handle.net/2060/19770018969 |
| 著者（英） | Nystrom, P.; Pao, S. P.; Seiner, J. M.; Manning, J. C. |
| 著者所属（英） | NASA Langley Research Center |
| 発行日 | 1977-05-01 |
| 言語 | eng |
| 内容記述 | Near field acoustic measurements were obtained for a model supersonic air jet perturbed by a screen. Noise reduction potential in the vicinity of the space shuttle vehicle during ground launch when the rocket exhaust flow is perturbed by a grid was determined. Both 10 and 12 mesh screens were utilized for this experiment, and each exhibited a noise reduction only at very low frequencies in the near field forward arc. A power spectrum analysis revealed that a modest reduction of from 3 to 5 decibels exists below a Strouhal number S sub t = 0.11. Above S sub t = 0.11 screen harmonics increased the observed sound pressure level. The favorable noise reductions obtained with screens for S sub t 0.11 may be of substantial interest for the space shuttle at ground launch. |
| NASA分類 | ACOUSTICS |
| レポートNO | 77N25913
NASA-TM-X-74034
REPT-2620 |
| 権利 | No Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/182076 |
