Spatial resolution correction for hot-wire anemometry in wall turbulence

We investigate spatial resolution issues in hot-wire anemometry measurements of turbulence intensity and energy spectra. Single normal hot-wire measurements are simulated by means of filtering direct numerical simulation (DNS) of turbulent channel flow at Res 1⁄4 934. Through analysis of the two-dimensional energy spectra from the DNS, the attenuation of the small-scale energy levels is documented, especially in the near-wall region. The missing energy displays anisotropic characteristics, and an attempt is made to model this using an empirical equation, thus providing a correction scheme for all wall normal locations. The empirical model is assessed using experimental boundary layer data and shown to effectively correct both the streamwise one-dimensional energy spectra and turbulence intensity at a Reynolds number significantly above that of the DNS.