Unsteady turbulent boundary layers and separation
Abstract
The eddy viscosity model with an inner (PrandtlVan Driest) and an outer (Clauser) layer is generalized for unsteady flow and the time dependent turbulent boundary layer equations are integrated numerically for transient or oscillatory outer flows. Comparisons with previous theoretical results indicate that the present method is at least as good as the others. Extensive comparisons with experimental data is also attempted for the first time. It appears that in a certain range of frequencies the agreement is satisfactory. Further some characteristic quantities like the mean velocity profile or the wall shear phase angle are predicted accurately but other properties, like the averaged fluctuations of the velocity, indicate large discrepancies. The present method is also capable of integrating past the point of zero skin friction and into regions of partially reversed flow. The phenomenon of separation in unsteady flow is also investigated.
 Publication:

AIAA, 13th Aerospace Sciences Meeting
 Pub Date:
 January 1975
 Bibcode:
 1975aiaa.meetR....T
 Keywords:

 Boundary Layer Equations;
 Boundary Layer Separation;
 Eddy Viscosity;
 Mathematical Models;
 Turbulent Boundary Layer;
 Unsteady Flow;
 Flow Velocity;
 Numerical Integration;
 Reversed Flow;
 Skin Friction;
 Time Dependence;
 Transient Response;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer