Difficulties in obtaining full-scale rotor low frequency noise measurements in wind tunnels are addressed via residual sound reflections due to non-ideal anechoic wall treatments. Examples illustrated with the Boeing-SMART rotor test in the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel facility demonstrated that these reflections introduced distortions in the measured acoustic time histories that are not representative of free-field rotor noise radiation. A simplified reflection analysis, based on the method of images, is used to examine the sound measurement quality in such "less-than-anechoic" environment. Predictions of reflection-adjusted acoustic time histories are qualitatively shown to account for some of the spurious fluctuations observed in wind tunnel noise measurements


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    Titel :

    A Study of Acoustic Reflections in Full-Scale Rotor Low Frequency Noise Measurements Acquired in Wind Tunnels


    Beteiligte:

    Kongress:

    American Helicopter Society Specialists'' Conference on Aeromechanics ; 2010 ; San Francisco, CA, United States


    Erscheinungsdatum :

    20.01.2010


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Keine Angabe


    Sprache :

    Englisch


    Schlagwörter :


    A Study of Acoustic Reflections in Full-Scale Rotor Low Frequency Noise Measurements Acquired Wind Tunnels

    Barbely, N.L. / Sim, B.W. / Kitaplioglu, C. et al. | British Library Conference Proceedings | 2010


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    Measurement of Automobile Aerodynamic Noise in Wind Tunnels - An Acoustic Comparison Test of Japanese Wind Tunnels

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