Two dimensional subsonic wind tunnel tests have been conducted on a 20% thickness: chord ratio circulation controlled elliptic aerofoil section equipped with forward and reverse blowing slots. Overall performance measurements were made over a range of trailing edge blowing momentum coefficients from 0 to 0.04; some included the effect of leading edge blowing. The effective incidence was determined experimentally and lift augmentations of 70 were obtained at low blowing rates. A detailed investigation of the trailing edge wall jet, using split film probes, hot wire probes and total head tubes, provided measurements of mean velocity components, Reynolds normal and shear stresses, and radial static pressure. Corrections for the effects of ambient temperature variation, flow angle and shear flow gradient upon the various probes were examined and some corrections for the low bandwidth of the split film probes proposed. In some cases, the effects of slot height and slot lip thickness were investigated. The results were mostly taken at a geometric incidence of 0°. The closure of the two dimensional angular momentum and continuity equations was examined using the measured data, with and without correction, and the difficulty of obtaining a satisfactory solution illustrated. The experimental results have led to some suggestions regarding the nature of the flow field which should aid the understanding of Coanda effect and the theoretical solution of highly curved wall jet flows.
|Date of Award||1981|