Measurements of the two-dimensional energy spectra of wall-turbulence at high Reynolds number

This paper describes a technique to experimentally measure the two-dimensional energy spectra of the streamwise velocity in wallturbulence. The technique is validated at low Reynolds numbers using Direct Numerical Simulation (DNS) data. It is found that a correction to the high wavenumber range of the energy spectra is required owing to physical limitations on minimum probe separation. The measurement technique and DNS-based correction scheme is employed in the University of Melbourne High Reynolds number (Re) wind-tunnel to measure the 2D spectra at high Re for the first time. The results are compared with attached eddy simulation models, showing that hierarchies of high-aspect ratio eddies are required to accurately capture the large-scale energy behaviour.