Contact line models for thin films

In the present work, we describe the dynamics of a moving contact line for thin films flowing down an inclined plane. Our focus is the problem of triple point located at the interface between the solid wall, the moving fluid and air, for example the spreading of a drop on a plane dry wall (horizontal or inclined) due to gravity and capillarity. In the first part, we explain how we can reduce to the Stokes equations and why the resulting problem is ill-posed. This singularity is removed by permitting the fluid to slip along the wall close to the contact line. Thus we manage to find a solution in H1 constructed by asymptotic expansions. Then we focus on the upstream dynamic of the flow, which is set to a thin film flow. We develop the classical system of Shallow-water equations (Saint-Venant equations) from the full Navier-Stokes system using the classical long-wavelength expansion. We obtain a set coupled equations for the flow depth and the flow-rate. In the neightboorhood of the contact line, we develop an asymptotic expansion of the steady Stokes system with slip at bottom in function of the capillary number. The solution in the vicinity of the contact line is developped in the inner region and the outer region. Then, a direct matching can be done (assuming dynamic and static angles are equals) or using an intermediate region (with different angles). This leads to two different families of models. Bringing together the upstream Shallow-water equations and the contact line models, we write a new Shallow-water model taking into account the dynamic of the moving contact line. Then, we deduce a simplier one-equation model for the film thickness. This model extends existing models with no slip at bottom to models with slip. Direct numerical simulations of the last models are performed, combining a moving contact line and a thin liquid film.

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Source https://theses.hal.science/tel-00777952
Author Roux, Marthe
Maintainer CCSD
Last Updated May 15, 2026, 04:35 (UTC)
Created May 15, 2026, 04:35 (UTC)
Identifier tel-00777952
Language fr
Rights https://about.hal.science/hal-authorisation-v1/
contributor Institut de Mathématiques de Toulouse UMR5219 (IMT) ; Université Toulouse Capitole (UT Capitole) ; Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse) ; Institut National des Sciences Appliquées (INSA)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Institut National des Sciences Appliquées (INSA)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Université Toulouse - Jean Jaurès (UT2J) ; Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Université Toulouse III - Paul Sabatier (UT3) ; Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Centre National de la Recherche Scientifique (CNRS)
creator Roux, Marthe
date 2012-12-06T00:00:00
harvest_object_id 5380a7e8-ab97-4ec7-a3ae-c8929a2c23de
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-10-22T00:00:00
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