Effect of an Extendable Slat on the Stall Behavior of a VR-12 Airfoil.
Abstract
Experimental and computational tests were performed on a VR- 1 2 airfoil to determine if the dynamic-stall behavior that normally accompanies high-angle pitch oscillations could be modified by segmenting the forward portion of the airfoil and extending it ahead of the main element. In the extended position the configuration would appear as an airfoil with a leading-edge slat, and in the retracted position it would appear as a conventional VR-12 airfoil. The calculations were obtained from a numerical code that models the vorticity transport equation for an incompressible fluid. These results were compared with test data from the water tunnel facility of the Aeroflight-dynamics Directorate at Ames Research Center. Steady and unsteady flows around both airfoils were examined at angles of attack between 0 deg and 30 deg. The Reynolds number was fixed at 200,000 and the unsteady pitch oscillations followed a sinusoidal motion described by alpha = alpha (m) + 10 deg sin(wt). The mean angle (alpha m)was varied from 10 deg to 20 deg and the reduced frequency from 0.05 to 0.20. The results from the experiment and the calculations show that the extended-slat VR-1 2 airfoil experiences a delay in both static and dynamic stall not experienced by the basic VR- 12 airfoil. Airfoil stall, Dynamic stall, Leading-edge slat, High-lift device.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1993
- Accession Number
- ADA274150
Entities
People
- C. Tung
- K. W. Mcalister
- P. P. De Hugues
Organizations
- National Aeronautics and Space Administration