Laminar Stall Prediction and Estimation of CL(max)

Abstract

A criterion for the prediction of laminar stall is developed from basic considerations of the laminar boundary layer theory. This criterion is applied to some NACA series 2-D airfoil sections and a 3-D wing that was wind tunnel tested. The correlation cases are presented for which freestream Mach number was approximately equal to 0.2 and freestream Reynolds number variations were in the range of 1 to 6 million. An estimation of CL<MAX) is made for cases where laminar stall is predicted. This criterion has been found useful both from the point of view of data analysis as well as for the design of a section of a 3-D wing for the purpose of delaying the occurrence of laminar stall. In addition, the criterion for the prediction of stall of a two-component airfoil with a leading edge slat is suggested.