Calculation of Unsteady Turbulent Boundary Layers

Abstract

An unsteady, two-dimensional boundary-layer solution procedure is used to predict two different types of incompressible turbulent mean flows, the Blasius and Howarth flows, with superimposed time-dependent harmonic oscillations. A simple algebraic mixing length model that includes a minor modification for unsteadiness in the inner part of the boundary layer was used. Computed results for the two different mean flows over a wide range of unsteady conditions are presented and compared with measured data and other numerical solutions. The overall agreement of the present solutions with measurements is very good, although details of unsteady characteristics are not completely resolved due to shortcomings in the closure model.