Interrelated Effects of Pitch Rate and Pivot Point on Airfoil Dynamic Stall
Abstract
Experimental investigations were conducted to study energetic dynamic stall vortices and the associated unsteady aerodynamics generated by a pitching NACA 0015 airfoil. The airfoil model was pitched from zero degrees to 60 degrees at constant pitch rates of 460 deg/sec, 920 deg/sec, and 1380 deg/sec about its quarter-chord, half-chord, and three quarter-chord positions. Extensive 35mm still photographs and 16mm high-speed movies, both employing smoke wire flow visualization, visually documented the initiation and development of the time dependent dynamic stall phenomena. Hot-wire anemometry measurements were also made which provided for more quantitative analysis of the unsteady separated flowfields. Pitch rate and pivot point were shown to have interrelated effects on the development of the dynamic stall flowfield. In many cases similar 'looking' flowfields were generated by different combinations of pitch rate and pivot point. However, significant differences were observed in the near-surface velocity profiles. (edc)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 14, 1985
- Accession Number
- ADA227926
Entities
People
- Hank E. Helin
- John M. Walker
Organizations
- Air Force Research Laboratory