Boundary-layer transition-to-turbulence studies are conducted in the Arizona State University Unsteady Wind Tunnel on a 45-degree swept airfoil. The pressure gradient is designed so that the initial stability characteristics are purely crossflow-dominated. Flow visualization and hot-wire measurements show that the development of the crossflow vortices is influenced by roughness near the attachment-line. Comparisons of transition location are made between a painted surface, a machine-polished surface, and a hand-polished surface. Then, isolated 6 micron roughness elements are placed near the attachment line on the airfoil surface under conditions of the final polish (0.25 micron rms). These elements amplify a centered stationary crossflow vortex and its neighbors, resulting in localized early transition. The diameter, height, and location of these roughness elements are varied in a systematic manner. Spanwise hot-wire measurements are taken behind the roughness element to document the enhanced vortices. These scans are made at several different chord locations to examine vortex growth.


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    Title :

    Effect of micron-sized roughness on transition in swept-wing flows



    Conference:

    AIAA, Aerospace Sciences Meeting and Exhibit ; 1993 ; Reno, NV, United States


    Publication date :

    1993-01-01


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English


    Keywords :


    Effect of micron-sized roughness on transition in swept-wing flows

    RADEZTSKY, JR., RONALD / REIBERT, MARK / SARIC, WILLIAM et al. | AIAA | 1993


    Effect of Isolated Micron-Sized Roughness on Transition in Swept-Wing Flows

    Ronald H. Radeztsky / Mark S. Reibert / William S. Saric | AIAA | 1999


    Role of Micron - Sized Roughness in Swept - Wing Transition

    Reibert, Mark S. / Radeztsky, Ronald H. / Takagi, Shohei et al. | SAE Technical Papers | 1992