AN EXAMINATION OF PERSEN'S THEORY ON TWO DIMENSIONAL TURBULENT BOUNDARY LAYER

摘要

In this paper we examine Persen's theory on the structure of wall bounded turbulent boundary layer with zero pressure-gradient in the light of recent measurements by Osterlund. The theory introduces the assumption that the entire turbulent boundary layer be divided into two regions e.g., an inner region wherein a nniversally valid structure prevails and an outer region which can be described by a new wake law. It is shown that the establishment of the theory depends on an experimentally supported relation between the nondimensional velocity at the end point of the boundary layer and the corresponding non-dimensional distance from the wall. The solution to the problem is achieved by another relation between this velocity and the local Reynolds number. The coefficients of skin-friction and velocity profiles, as obtained here for a range of high Reynolds numbers are found to be in good agreement with Osterlund's data. Finally, the discrepancies between the earlier measurements of Weighardt/Tillmann and Osterlund's measurements are explained in the context of their applicability to the verification of Persen's theory.