Quasi-steady quasi-homogeneous (QSQH) description of the relationship between large-scale and small-scale motions in near-wall turbulence

Abstract

The validity of the recently proposed hypothesis that the influence of large-scale motions on the near-wall turbulence is quasisteady is investigated by quantitative comparisons with the data obtained by direct numerical simulations of a turbulent channel flow. Large-scale motions are filtered by a Fourier cut-off filter multi-objectively optimised to increase the correlation between large-scale motions near and away from the wall while decreasing the correlation between small-scale motions. The quasi-steady hypothesis is found to be approximate. It is also found that adding non-linear terms into calculations will improve the accuracy of the prediction.