Turbulent boundary layers on surfaces of mild longitudinal curvature

Detailed measurements were made on a rig in which boundary layers that have developed on flat surfaces enter a curved section with concave and convex wall radii about 100 times the initial boundary layer thickness. The data include second, third, and fourth-order mean products of velocity fluctuations and provide a consistent picture of the effects of curvature on structure parameters. Analysis shows that in general these structure parameters increase on the concave (destablized) side and decrease on the convex side, but some interesting nonmonitonic trends occur. This nonlinearity is analogous to that found in buoyant flows.