Comparative measurements in the canonical boundary layer at Reδ2≤6×104 on the wall of the German–Dutch windtunnel

Mean velocity and Reynolds-stress profiles were measured in the incompressible turbulent boundary layer with zero pressure gradient on the aerodynamically smooth sidewall of the German–Dutch windtunnel. Data were taken at Reynolds numbers Reδ2, based on momentum thickness δ2 of 2×104, 4×104, and 6×104 by means of four different types of hot-wire probes (three-wire probes, X wire, and normal-wire probes). There are also measurements of skin friction and of spectra. The data compare well with the few available other measurements, and all profiles show independence of Reynolds number in the outer region of the boundary layer when plotted against y/Δ, where Δ is the Rotta–Clauser length.