An Analytical Method for Calculating Turbulent Separated Flows Due to Adverse Pressure Gradients.

A method has been developed for calculating incompressible turbulent boundary-layer characteristics smoothly across the separation point under the influence of an adverse pressure gradient. A special study of the separation point singularity is the basis of the method. Further work is needed to extend the method far enough downstream so that the complete separation region can be treated. The method contains a new formulation of the eddy viscosity to account for pressure gradients and includes the effects of surface curvature in the equations of motion. Excellent agreement is obtained between the theory and the separation measurements of Newman on an airfoil. Good agreement is obtained between theory and the measurements of Schubauer and Klebanoff except near separation. The normal pressure gradients existing in the experiments of Newman and of Schubauer and Klebanoff have been evaluated using the data. Preliminary indications are that normal gradients may not be important in calculating the boundary-layer characteristics.