| タイトル | Fan Noise Source Diagnostic Test: Vane Unsteady Pressure Results |
| 本文（外部サイト） | http://hdl.handle.net/2060/20020084621 |
| 著者（英） | Envia, Edmane |
| 著者所属（英） | NASA Glenn Research Center |
| 発行日 | 2002-08-01 |
| 言語 | eng |
| 内容記述 | To investigate the nature of fan outlet guide vane pressure fluctuations and their link to rotor-stator interaction noise, time histories of vane fluctuating pressures were digitally acquired as part of the Fan Noise Source Diagnostic Test. Vane unsteady pressures were measured at seven fan tip speeds for both a radial and a swept vane configuration. Using time-domain averaging and spectral analysis, the blade passing frequency (BPF) harmonic and broadband contents of the vane pressures were individually analyzed. Significant Sound Pressure Level (SPL) reductions were observed for the swept vane relative to the radial vane for the BPF harmonics of vane pressure, but vane broadband reductions due to sweep turned out to be much smaller especially on an average basis. Cross-correlation analysis was used to establish the level of spatial coherence of broadband pressures between different locations on the vane and integral length scales of pressure fluctuations were estimated from these correlations. Two main results of this work are: (1) the average broadband level on the vane (in dB) increases linearly with the fan tip speed for both the radial and swept vanes, and (2) the broadband pressure distribution on the vane is nearly homogeneous and its integral length scale is a monotonically decreasing function of fan tip speed. |
| NASA分類 | Acoustics |
| レポートNO | AIAA Paper 2002-2430
NAS 1.15:211808
NASA/TM-2002-211808
E-13503 |
| 権利 | No Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/64757 |
