Investigation of Separation Models for the Prediction of Cℓmax

A method for calculating the flow about airfoils up to and beyond the stall is described. It is an iterative procedure between potential flow and boundary layer solutions. The separated region is modeled in the potential flow analysis using free vortex sheets which require an inner iteration to establish their shapes. Calculated and experimental results are compared for a GA(W)-1 airfoil at two Reynolds numbers, 6.3 x 106 and 2.1 x 106. The results are very encouraging, but they depend on a wake length factor which requires further investigation. Future work will include incorporating compressibility corrections in the method; this is expected to improve the calculations at and beyond Cℓmax.