Wall Stress Measurements in Two-Dimensional Turbulent Channel and Boundary-Layer Flows, and the Wall Layer Differences

Abstract

Measurements of time-mean velocity, longitudinal, normal and lateral velocity fluctuation intensities (u', v', w') and of wall shear stress have been made in turbulent flows in a flat channel and in boundary layers (zero pressure gradient). The profiles of u', v', w follow a similar pattern, to a reasonable approximation. The wall shear stresses obtained by different techniques have been compared. The same equipment was employed in boundary-layer measurements, and the results are compared with those obtained in channel flows. Comparisons of fluctuation intensities, and two constants A and B in the universal law of the wall, where A is the slop constant and B is the 'slip' within the viscous layer interposed between the smooth wall and the fully turbulent flow, have been made with values obtained by earlier investigators for both channel and boundary-layer flows.