Scaling properties of the mean wall-normal velocity in zero-pressure-gradient boundary layers

Abstract

The scaling properties of the mean wall-normal velocity V(x,y) in zero-pressure-gradient laminar and turbulent boundary-layer flows are investigated using numerical simulation data, physical experiment data, and integral analyses of the governing equations. The maximum mean wall-normal velocity V and the boundary-layer thickness δ are evidenced to be the proper scaling for V over most if not all of the boundary layer. This is different from the behavior of the mean streamwise velocity U or the turbulent shear stress T=-ρ(uv), which depend on different characteristic length scales in the regions near and away from the surface, respectively. The reason for this apparent difference in scaling b..