Universality of probability density functions in turbulent channel flow

Probability density functions (PDFs) of the fluctuating velocity components, as well as their first and second derivatives, are calculated using data from the direct numerical simulations (DNS) of fully developed turbulent channel flow. It is observed that, beyond the buffer region, the PDF of each of these quantities (except for u,y), is independent of the distance from the channel wall. It is further observed that, beyond the buffer region, the PDFs are also independent of Reynolds number. Similar behavior is observed for the PDFs of the second derivatives. The pseudodissipation rate of kinetic energy exhibits lognormal behavior.