Mercredi 29 février à 11h dans l'amphithéâtre de l'ENSTA ParisTech site de Palaiseau : Séminaire de l'UME (exclusivement en Anglais) sur le thème "On the transition to/from turbulence in channel flows" présenté par Takahiro Tsukahara de Tokyo University of Science.
Résumé :
In this talk, we present a series of DNSs conducted in two types of plane channel flows, i.e., plane Poiseuille flow and plane Couette flows, considering the subcritical-transition regime with the use of large aspect-ratio computational domains. Both flows give rise to coexisting laminar and turbulent equilibrium regions in the form of oblique stripes, so-called the turbulent stripe. In addition, through the long-term tracking of an isolated turbulent spot, we confirmed that the spot developed into the turbulent stripes in the plane Poiseuille flow at transitional Reynolds numbers. We have also found that, when subjected to stabilizing rotation, the Couette turbulence is locally quenched and exhibits the stripe pattern. In this context, the turbulence stripe can be seen as an intrinsic phenomenon for the transition and the reverse transition in channel flows.