Prediction of turbulent boundary layers in the vicinity of separation
Abstract
Several aspects of the prediction of separating twodimensional incompressible turbulent boundary layers are considered. A turbulent boundary layer prediction program was modified to account for the normal stress terms in the momentum and the turbulence energy equations, which become important near separation. On the whole, predictions were improved up to the beginning of intermittent separation, or where backflow begins on an intermittent basis. A model was developed and used to predict the intermittent separation location based on the experimental observation that intermittent separation begins when the local turbulence intensity is first greater than onethird. Because the normal stresses appear to oppose the pressure gradient effect near separation, the basis for a pressure gradient modified lawofthewall mean velocity profile after intermittent separation is questionable. In predictions of test flows, the traditional and McDonald lawofthewall velocity profiles were used with only small differences in the results upstream of intermittent separation.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 January 1977
 Bibcode:
 1977STIN...7814311S
 Keywords:

 Prediction Analysis Techniques;
 Separated Flow;
 Turbulent Boundary Layer;
 Two Dimensional Flow;
 Boundary Layer Separation;
 Flow Distribution;
 Mathematical Models;
 Pressure Gradients;
 Turbulence Effects;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer