Role of Micron - Sized Roughness in Swept - Wing Transition Conference Paper uri icon


  • Stability and transition experiments are conducted in the Arizona State University Unsteady Wind Tunnel on a 45 swept airfoil. The pressure gradient is designed so that transition and stability are purely crossflow-dominated. Flow visualization and hot-wire measurements show that the development of the crossflow vortices is influenced by roughness near (not at) the attachment-line. Comparisons of transition location are made between a painted surface (distributed 9 m peaks and valleys on the surface), a machine-polished surface (0.5 m rms finish), and a hand-polished surface (0.25 m rms finish). Then, isolated 6-9 m roughness elements are placed near the attachment line on the airfoil surface under conditions of the final polish (0.25 m rms). These elements amplify a centered stationary crossflow vortex and its neighbors, resulting in localized early transition. The diameter and height 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. 1992 Society of Automotive Engineers, Inc.

name of conference

  • SAE Technical Paper Series

published proceedings

  • SAE Technical Papers

author list (cited authors)

  • Radeztsky, R. H., Reibert, M. S., Saric, W. S., & Takagi, S.

citation count

  • 1

complete list of authors

  • Radeztsky, Ronald H||Reibert, Mark S||Saric, William S||Takagi, Shohei

publication date

  • December 1992