During the past decade, numerous major effects have addressed the question of how to control or alleviate dynamic stall effects on helicopter rotors, but little concrete evidence of any significant reduction of the adverse characteristics of the dynamic stall phenomenon has been demonstrated. Nevertheless, it is important to remember that the control of dynamic stall is an achievable goal. Experiments performed at the US Army Aeroflight-dynamics Directorate more than a decade ago demonstrated that dynamic stall is not an unavoidable penalty of high amplitude motion, and that airfoils can indeed operate dynamically at angles far above the static-stall angle without necessarily forming a stall vortex. These experiments, one of them featuring a slat that was designed from static airfoil considerations, showed that unsteadiness can be a very beneficial factor in the development of high-lift devices for helicopter rotors. The experience drawn from these early experiments is now being focused on a program for the alleviation of dynamic-stall effects on helicopter rotors. The purpose of this effort is to demonstrate that rotor stall can be controlled through an improved understanding of the unsteady effects on airfoil stall and to document the role of specific means that lead to stall alleviation in the three dimensional unsteady environment of helicopter rotors in forward flight. The first concept to be addressed in this program will be a slatted airfoil. A two dimensional unsteady Navier-Stokes code has been modified to compute the flow around a two-element airfoil.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen


    Exportieren, teilen und zitieren



    Titel :

    The quest for stall-free dynamic lift


    Beteiligte:
    Tung, C. (Autor:in) / Mcalister, K. W. (Autor:in) / Carr, Lawrence W. (Autor:in) / Duque, E. (Autor:in) / Zinner, R. (Autor:in)


    Erscheinungsdatum :

    1992-03-01


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Keine Angabe


    Sprache :

    Englisch


    Schlagwörter :


    Quest for Stall-Free Dynamic Lift

    C. Tung / K. W. Mcalister / L. W. Carr et al. | NTIS | 1992



    MOTOR STALL AND TRAILER LIFT

    RONAN TESSA / ZIPARO VITTORIO / KLEIN LAWRENCE et al. | Europäisches Patentamt | 2024

    Freier Zugriff

    Motor stall and trailer lift

    RONAN TESSA / ZIPARO VITTORIO / KLEIN LAWRENCE et al. | Europäisches Patentamt | 2023

    Freier Zugriff

    MOTOR STALL AND TRAILER LIFT

    RONAN TESSA / ZIPARO VITTORIO / KLEIN LAWRENCE et al. | Europäisches Patentamt | 2022

    Freier Zugriff