Some observations on Reynolds number scaling in wall-bounded flows

High Reynolds number wind tunnels are essential tools for testing theories of turbulence. This need has led to the construction of tunnels that use compressed gases as the working fluid, and such facilities have given new insights into the behavior of turbulence in wall-bounded flows. Here, we focus on results obtained at Princeton using the Superpipe and the High Reynolds number Testing Facility that have given us new insights into the behavior of wall-bounded flows, in particular, fully developed pipe flow, and turbulent boundary layers in zero pressure gradients.