Two alternative approaches area developed to calculate blade-vortex interaction airloads on helicopter rotors, second-order lifting-line theory and a lifting-surface theory correction. The common approach of using a larger vortex core radius to account for lifting-surface effects is quantified. The second-order lifting-line theory also improves the modeling of low aspect-ratio blades yawed flow, and swept tips. Calculated results are compared with wind-tunnel measurements of lateral flapping, and with flight test measurements of blade section lift on SA349/2 and H-34 helicopter rotors. The tip vortex core radius required for good correlation with the flight test data is about a 20-percent chord, which is within the range of measured viscous core sizes for helicopter rotors.


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    Title :

    Calculation of blade-vortex interaction airloads on helicopter rotors


    Contributors:

    Published in:

    Publication date :

    1989-05-01



    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English


    Keywords :