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Interaction between a large-scale structure and near-wall structures in channel flow. (English) Zbl 1065.76553
Summary: Direct numerical simulation of a turbulent channel flow in a periodic domain of relatively wide spanwise extent, but minimal streamwise length, is carried out at Reynolds numbers \(Re_\tau = 137\) and 349. The large-scale structures previously observed in studies of turbulent channel flows using huge computational domains are also shown to exist even in the streamwise-minimal channels of the present study. Moreover, the limitation of the streamwise length of the domain enforces the interaction between large-scale structures and near-wall structures, which consequently makes it tractable to extract a simple cycle of processes sustaining the structures in the present channel flow. It is shown that the large-scale structures are generated by the collective behaviour of near-wall structures, and that the generation of the latter is in turn enhanced by large-scale structures. Hence, near-wall and large-scale structures interact in a co-supporting cycle.

76F10 Shear flows and turbulence
76F65 Direct numerical and large eddy simulation of turbulence
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