Unsteady Aerodynamic Forces at Low Airfoil Pitching Rates
Abstract
Experiments were conducted on a NACA-0015 airfoil undergoing low constant pitch rates to study the effects of dynamic stall formation on the airfoil upper surface pressure field. The airfoil was pitched about pivot locations of 0.25c, 05c, and 0.75c at nondimensional pitch rates below 0.2. Lift and drag coefficients were evaluated for all cases, and smoke flow visualization at low pitch rates was studied for the quarter chord pivot location. Results indicate that the greatest increases in lift due to the pitching motion occur prior to the nondimensional pitch rate of 0.1 for all three pivot locations. The effects of pitch rate on the maximum lift and drag values appear similar for the three pivot locations studied. Lift to drag ratios show significant enhancement even at very low nondimensional rates. Flow visualization indicates that the leading edge dynamic stall vortex is present even at very low nondimensional pitch areas. Keywords: Aerodynamic lift/drag; Pitch motion; Airfoils; Leading edges; Stall vortices; Aerodynamic forces; Unsteady flow; Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 06, 1988
- Accession Number
- ADA228102
Entities
People
- C. Kedzie
- J. Albertson
- T. Troutt
Organizations
- Air Force Research Laboratory