Studies Of An Integral Method For Calculating Time Dependent Turbulent Boundary Layers

An integral boundary-layer method is examined for its applicability to unsteady turbulent boundary layers. The method employs an analytical velocity profile formulation modeled after the law of the wall and the law of the wake and recently applied successfully to calculation of steady separated turbulent boundary layers. Analytical solutions developed from a small perturbation analysis indicate the method is valid for unsteady flow over a certain range of frequencies. Good comparisons were obtained between the linearized theory and results produced by a finite-difference solution of the complete nonlinear unsteady boundary-layer equations. Examination of the nature of the integral equations in the vicinity of a point of zero wall shear stress indicates that that point does not necessarily correspond to a point of separation in unsteady flow. That result is also consistent with the results of other researchers. (Author).