A Theoretical Investigation of Unsteady Separation Phenomena Related to Dynamic Stall
Abstract
The objective of this research was to identify the principal cause and effect relationships in dynamic stall at large Reynolds numbers, as well as possible means for controlling the process. At high Reynolds numbers, it is demonstrated the formation of the dynamic stall vortex initiates for all airfoil shapes via an unsteady separation of the boundary layer near the leading edge. The stall vortex ultimately detaches from the upper surface by provoking an unsteady separation of the surface layer near midchord. At least two methods of controlling separation at various stages in the cycle have been identified, namely (1) suction near the leading nose or at midchord and (2) a moving portion of the surface. The present work shows how separation can be suppressed and makes significant contributions to the theory of unsteady boundary-layer separation. A general analysis of unsteady two-dimensional airfoil maneuvers was initiated and is currently under study as a possible third means of control.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1993
- Accession Number
- ADA271865
Entities
People
- J. D. Walker
Organizations
- Lehigh University