Experiments on the Relatively Thick, Turbulent Boundary Layers on a Rotating Cylinder in Axial Flows : 2nd Report, Flows under Pressure Gradients

Abstract

Measurements of velocity distribution in three turbulent boundary layers on a circular cylinder spinning in axial flows, two with adverse pressure gradients and one with favorable pressure gradient, are presented and discussed. The peripheral shear-stress distribution in the boundary layer is calculated numerically from measured mean velocity profiles. On the basis of them near the wall, the law of the wall is considered. A formula for the logarithmic velocity distribution in the peripheral direction is deduced on the usual assumption that the wall layer and the outer layer overlap each other. This expression succeeds in depicting the measured velocity profiles. A Richardson number describing the effect of rotation or streamline curvature on a turbulent flow is used in an attempt to clarify the character of these flows; the changes in the constants in the logarithmic formula for the velocity distribution are represented in terms of the Richardson number.