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Accueil du site > Séminaires > Archives séminaires > Séminaires 2019 > 30 septembre 2019, 11h00 454 A. Anne Juel (Manchester, UK) : "Unstable front propagation". .

30 septembre 2019, 11h00 454 A. Anne Juel (Manchester, UK) : "Unstable front propagation".

Sauf mention contraire, les séminaires et les soutenances se déroulent à 11h30 en salle 454A du bâtiment Condorcet.

Exceptional schedule : 11h00 in room 454 A Monday 30/09/2019

Unstable front propagation

Prof. Anne Juel

Physics of Fluids and Soft Matter Group, Department of Physics & Astronomy

The University of Manchester, United Kingdom

Front-propagating systems provide some of the most fundamental physical examples of interfacial instability and pattern formation. However, their nonlinear dynamics are rarely addressed. We focus on the canonical viscous fingering instability, which arises when a more viscous fluid is displaced by a less viscous one in a quasi-two-dimensional channel. For example, this system exhibits a sub-critical transition at finite values of the driving parameter from a steadily propagating finger, which is linearly stable for all values of the driving parameter, to an unsteady, disordered front. This scenario is reminiscent of the transition to turbulence in shear flows where weakly unstable solutions, referred to as ’edge states’, determine the basin boundary separating initial conditions decaying to laminar flow from those growing to turbulence. In this talk, we explore the role of unstable modes of propagation (and edge states) in the dynamics of two viscous fingering systems exhibiting sub-criticality : a rigid channel with a small depth perturbation and a channel where the top boundary has been replaced with an elastic sheet.

Contact : Équipe séminaires / Seminar team - Published on / Publié le 18 septembre 2019

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