Turbulent bands in plane-Poiseuille flow at moderate Reynolds numbers
2015 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 27, no 4, 041702Article in journal (Refereed) Published
In this letter, we show via numerical simulations that the typical flow structures appearing in transitional channel flows at moderate Reynolds numbers are not spots but isolated turbulent bands, which have much longer lifetimes than the spots. Localized perturbations can evolve into isolated turbulent bands by continuously growing obliquely when the Reynolds number is larger than 660. However, interactions with other bands and local perturbations cause band breaking and decay. The competition between the band extension and breaking does not lead to a sustained turbulence until Re becomes larger than about 1000. Above this critical value, the bands split, providing an effective mechanism for turbulence spreading.
Place, publisher, year, edition, pages
2015. Vol. 27, no 4, 041702
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-169364DOI: 10.1063/1.4917173ISI: 000353835700002OAI: oai:DiVA.org:kth-169364DiVA: diva2:820750
QC 201506122015-06-122015-06-122015-06-12Bibliographically approved