CFD method with a grid spacing on the order of the blade chord at the microphone. Results are in general agreement with wind tunnel and flight test data to within 4 dB. Mid-to-high frequency noise content cannot be predicted by the direct CFD method due to grid spacing constraints and numerical limitations. Large discrepancies of up to 20 dB, in the mid-frequencies, are found especially at conditions dominated by impulsive noise fluctuations associated with blade-vortex interactions. A conventional 'on-surface' acoustic analogy approach is better at predicting the overall noise at lower advance ratios where impulsive noise dominates. At higher advance ratios where thickness noise becomes more important, low frequency noise tends to be underpredicted. It is speculated that this discrepancy is due to the flow-field effects off the blade tips not accounted for in the 'on-surface' modeling.


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    Title :

    On power and actuation requirement in swashplateless primary control using trailing-edge flaps


    Additional title:

    Über Leistungs- und Aktorikanforderungen bei der taumelscheibenlosen Primärregelung mit Hinterkantenklappen


    Contributors:

    Published in:

    Publication date :

    2010


    Size :

    17 Seiten, 20 Bilder, 18 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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