Predictions of separated and transitional boundary layers under low-pressure turbine airfoil conditions using an intermittency transport equation

A new transport equation for the intermittency factor was proposed to predict separated and transitional boundary layers under low-pressure turbine airfoil conditions. The intermittent behavior of the transitional flows is taken into account and incorporated into computations by modifying the eddy viscosity, μt , with the intermittency factor, y. Turbulent quantities are predicted by using Menter's two-equation turbulence model (SST). The intermittency factor is obtained from a transport equation model, which not only can reproduce the experimentally observed streamwise variation of the intermittency in the transition zone, but also can provide a realistic cross-stream variation of the intermittency profile. In this paper, the intermittency model is used to predict a recent separated and transitional boundary layer experiment under low pressure turbine airfoil conditions. The experiment provides detailed measurements of velocity, turbulent kinetic energy and intermittency profiles for a number of Reynolds numbers and freestream turbulent intensity conditions and is suitable for validation purposes. Detailed comparisons of computational 'Postdoctoral Researcher, Member AIAA. t Associate Professor, Senior Member AIAA. Associate Fellow AIAA § Aerospace Engineer, Senior Member AIAA. Copyright ©2001 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. results with experimental data are presented and good agreements between the experiments and predictions are obtained.