Experimental Investigation of the High Velocity Coanda Wall Jet Applied to Bluff Trailing Edge Circulation Control Airfoils
Abstract
A two-dimensional experimental investigation, intended to probe the mechanism for reduction in performance of circulation control elliptic airfoils in compressible flow, was conducted subsonically on a 20-percent-thick modified elliptic profile employing high Coanda wall jet velocities. The results include detailed pressure distributions (both normal and chordwise) and trailing edge shear stress measurements made with a hot film anemometer for a range of jet slot heights and jet total pressures corresponding to high subsonic, sonic, and supersonic jet velocities. Jet Mach numbers of almost 1.3 were found to have no adverse effects on the airfoil performance, and the degrading jet detachment phenomenon was never encountered. Significant differences in the jet flow field with and without an external free stream were noted, as was the deviation of the static pressure across the jet from a constant value as assumed in conventional boundary layer analysis. Airfoil lift performance was found to vary with slot height, and the detailed shear stress measurement enabled location of the jet separation point. Also discussed is the calibration and use of the hot film shear stress probe.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1975
- Accession Number
- ADA019417
Entities
People
- David W Taylor
- Robert J. Englar