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Selective opposition-like control of large-scale structures in wall-bounded turbulence

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Peer-reviewed

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Authors

Ibrahim, JI 
Guseva, A 
Garcia Mayoral, Ricardo  ORCID logo  https://orcid.org/0000-0001-5572-2607

Abstract

jats:titleAbstract</jats:title> jats:pWe investigate the effect of controlling large-scale, logarithmic-layer turbulent structures, which have a characteristic size and aspect ratio that scale with the distance from the wall. The aim is to quantify the effect of suppressing these structures while leaving the near-wall turbulent dynamics unaltered. By affecting only the logarithmic-layer structures, it might be possible to isolate their contribution to the drag from that of the other scales in the flow. We conduct direct numerical simulations of turbulent channel flows at friction Reynolds number jats:italicRejats:subT</jats:sub> </jats:italic> ?s 500-1000 and artificially remove certain streamwise and spanwise wavelengths of the wall-normal velocity across a range of heights. The wavelengths chosen depend on the target height (and size) of the structures that we wish to target. When these wavelengths are removed, we observe a positive, outward shift of the mean velocity profile above the target height, due to a local reduction in Reynolds shear stress, and a subsequent increase in viscous stress. Our preliminary results suggest that this shift in the mean velocity profile scales in outer units.</jats:p>

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Paper

Journal Title

Journal of Physics: Conference Series

Conference Name

Journal ISSN

1742-6588
1742-6596

Volume Title

1522

Publisher

IOP Publishing