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Quasi-steady modulation of near-wall turbulence
We investigate a hypothesis that the response of the near-wall turbulence to large-scale structures is quasi-steady. The most natural and compact form of expressing this is given by the usual Reynolds-number-independent representation of flow quantities scaled in wall variables, in which, however, in the definition of wall units the mean skin friction is replaced by large-scale low-pass-filtered fluctuating skin friction. We demonstrate that such a representation linearized assuming that the large-scale fluctuations are small as compared to the mean quantities leads to explicit theoretical expressions for the superposition and modulation coefficients of the empirical predictive models of the skin friction and streamwise fluctuating velocity found earlier. It is found that the theoretical predictions agree well with the coefficients determined experimentally.Author(s):
Sergei Chernyshenko
Imperial College London
United Kingdom
Ivan Marusic
University of Melbourne
Australia
Romain Mathis
Université Lille Nord de France
France