An acoustic and aerodynamic study was made of a 26%-scale unpowered Boeing 777 aircraft semispan model in the NASA Ames 40- by 80-Foot Wind Tunnel for the purpose of identifying and attenuating airframe noise sources. Simulated approach and landing configurations were evaluated at Mach numbers between 0.12 and 0.24. Cruise configurations were evaluated at Mach numbers between 0.24 and 0.33. The research team used two Ames phased-microphone arrays, a large fixed array and a small traversing array, mounted under the wing to locate and compare various noise sources in the wing high-lift system and landing gear. Numerous model modifications and noise alleviation devices were evaluated. Simultaneous with acoustic measurements, aerodynamic forces were recorded to document aircraft conditions and any performance changes caused by the geometric modifications. Numerous airframe noise sources were identified that might be important factors in the approach and landing noise of the full-scale aircraft. Several noise-control devices were applied to each noise source. The devices were chosen to manipulate and control, if possible, the flow around the various tips and through the various gaps of the high-lift system so as to minimize the noise generation. Fences, fairings, tip extensions, cove fillers, vortex generators, hole coverings, and boundary-layer trips were tested. In many cases, the noise-control devices eliminated noise from some sources at specific frequencies. When scaled to full-scale third-octave bands, typical noise reductions ranged from 1 to 10 dB without significant aerodynamic performance loss.


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    Titel :

    Aeroacoustic Study of a 26%-Scale Semispan Model of a Boeing 777 Wing in the NASA Ames 40- by 80-Foot Wind Tunnel


    Beteiligte:

    Erscheinungsdatum :

    2004-10-01


    Medientyp :

    Report


    Format :

    Keine Angabe


    Sprache :

    Englisch


    Schlagwörter :


    XV- 15 Aeroacoustic Testing at NASA Ames

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    XV-15 Aeroacoustic Testing at NASA Ames

    Light, J. S. / Kitaplioglu, C. / Acree, C. W. et al. | British Library Conference Proceedings | 1997


    Wind-tunnel investigation of 4-foot-diameter ducted fan mounted on tip of Semispan wing

    Yaggy, P.F. / Mort, K.W. | Engineering Index Backfile | 1961


    XV-15 aeroacoustic testing at NASA Ames

    Light, J.S. / Kitaplioglu, C. / Acree, C.W. | Tema Archiv | 1997


    Computational simulation of a semispan wing in a wind tunnel

    Olsen, Michael / Rizk, Yehia | AIAA | 1998