Laboratoire de Mécanique des Fluides et d'Acoustique - UMR 5509

LMFA - UMR 5509
Laboratoire de Mécanique des Fluides et d’Acoustique
Lyon
France


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Accueil > Activités de Recherche > Turbulence et Instabilités > Séminaires informels

R. Usha, Department of Mathematics, IIT Madras, Chennai, India. Invited professor at UCBL.

Miscible Two-Fluid flow down an incline : stability analysis

Mardi 20 juin 2017, 13h, ECL bât I11 salle de réunion 1er étage

Miscible Two-Fluid flow down an incline : stability analysis

In this talk, we demonstrate that miscible two-fluid free surface flows of varying viscosity down an inclined substrate have different stability characteristics from both immiscible two layer flows and flows with viscosity gradients spanning the entire flow. Existence of new instability modes are shown, when the critical layer of the dominant unstable mode is located within the viscosity gradient. At moderate miscibility, a lubricating configuration with less viscous fluid adjacent to the wall is most stable, which is in contrast with the immiscible case, in which lubrication configuration is always destabilizing. The role of simultaneous occurrence of growing overlap modes under certain conditions in triggering nonlinearities is an interesting question for the future.

Neutral boundaries of the co-existing overlap modes (O1,O2) and a Tollen Schlichting mode (TS) for different locations of the viscosity gradient layer in the lubricating configuration (m=1,5)
Neutral boundaries of the co-existing overlap modes (O1,O2) and a Tollen Schlichting mode (TS) for different locations of the viscosity gradient layer in the lubricating configuration (m=1,5)

The talk is based on the results published in Linear Stability of Miscible two-fluid Flow down an Incline R.Usha, Outi Tammisola, Rama Govindarajan,
Physics of Fluids, 2013