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Heat and Fluid Flow

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Many processes at different scales couple fluid flow and heat or mass transfer, from thin films interacting with a surrounding gas to convection in planetary interiors. Our research activity aims at understanding this coupling.

Some of our activities focus on natural phenomena, such as the internal dynamics of Earth and Venus, submarine hydrothermal fields, and the microclimates of caves. Other studies aim to understand industrial processes, such as instabilities of falling films interacting with a gas and the formation of coatings by drying dispersions of small particles.

Our approach is to develop in-depth physical understanding by using well-characterized model systems together with laboratory experiments to reveal the mechanisms involved.

Permanent members:

A. Davaille, G. Dietze, F. Doumenc, B. Guerrier, G. Kasperski, J. Martin, S. Mergui, N. Ribe

Non Permanent members:

P. Freydier (PostDoc), N. Sgreva (PhD), M. Zhou (Visiteur)

Former Members:

D. Brand (PhD, 2016), M. Dey (PostDoc, 2015), G. Gerardi (PhD, 2018), N. Kofman (PhD, 2014), Y. Li (PostDoc, 2018), A. Salvador (PhD, 2018), A. Sibrant (PostDoc, 2017), E. Sultan (TA, 2016), B. Xu (PhD, 2016)

Dynamics of three-dimensional wavy liquid films

G. Dietze

Collaborations : B. Scheid (ULB, Brussels), W. Rohlfs and Reinhold Kneer (RWTH Aachen)

Three-dimensional waves developing on the free surface of falling liquid films intensify convective transport in the adjacent phases, which influences the efficiency of multiphase processes such as distillation. Here, we study the effect of these surface waves on the velocity field and vice-versa by way of full numerical simulations (VOF-CSF method).

G. F. Dietze, W. Rohlfs, K. Nährich, R. Kneer and B. Scheid J. Fluid Mech. 743, 75 (2014)

Dynamics of free subduction

N. Ribe
Collaboration : Z. Li (Chinese Academy of Sciences)

Subduction, the gravity-driven sinking of oceanic lithosphere into the Earth’s mantle, is a major component of plate tectonics. We are building three-dimensional flow models of subduction to understand the factors that control the diverse morphologies of subducted plates revealed by seismic tomography, focussing on the interaction of the plates with the phase-change boundary at 660 km depth in the mantle. The image shows three possible plate morphologies depending on the ratio of the viscosity of the plate itself to that of the surrounding mantle.

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Falling liquid film in interaction with a gas

G. Dietze, C. Ruyer-Quil

Heat and/or mass transfer between a liquid and gaseous phase can be realized with the help of falling liquid films. These flows are unstable with respect to interfacial disturbances and, as a result, develop surface waves, which intensify the underlying transfer mechanisms. The image on the left shows streamlines within a liquid film and its surrounding gaseous atmosphere (top: counter-current, fixed reference frame; bottom: co-current, moving reference frame). These representations evince the occurrence of several wave-induced vortices.

G. F. Dietze, C. Ruyer-Quil J. Fluid Mech. 722, 348 (2013)

Polycrystal mechanics and mantle flow

N. Ribe
Collaborations : O. Castelnau (Arts et Métiers Paris Tech), R. Hielscher (Tech. Univ. Chemnitz, Germany)

When rocks in Earth's mantle deform, their constituent crystals take on a non-random crystal preferred orientation (CPO) that can be detected using seismic waves. To interpret such CPO in terms of mantle flow, we are developing a theory of polycrystal mechanics that can predict how individual crystals rotate during deformation. The figure shows a thinsection of a typical mantle rock viewed under polarized light.

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Instabilités 3D d'un film tombant

N. Kofman, S. Mergui, C. Ruyer-Quil

Un film liquide tombant sur un plan incliné se déstabilise pour former une onde solitaire composée d'une onde principale précédée de petites ondes capillaires. Ces ondes capillaires se déstabilisent à leur tour pour générer des motifs tridimensionnels. Les conditions d'apparition de ces instabilités 3D sont étudiées expérimentalement grâce à des cartes d'épaisseur de film obtenues par une méthode optique de type Schlieren.

J. of Fluid Mechanics, 757, (2014), doi: 10.1017/jfm.2014.506

Thin film deposit in a dip-coating-like process

M. Dey, F. Doumenc, B. Guerrier
Collaborations: J. Leng, C. Loussert, J.B. Salmon (LOF, CNRS)

In coating achieved by solvent evaporation from a polymer solution or a colloidal dispersion, complex phenomena occur in the vicinity of the contact line where the evaporation flux is maximum. Hydrodynamics and evaporation may induce self patterning, as illustrated in the image (left) for a silica colloidal suspension (deposit height ∼ 1 µm; wavelength ∼ 100µm).

F. Doumenc et al. Langmuir 32, (2016)
doi: 10.1021/acs.langmuir.6b02282

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Climatology and vermiculation in caves

F. Doumenc, B. Guerrier, J.-P. Hulin, J. Martin, S. Mergui
Collaborations : P.Y. Jeannin (ISSKA, Suisse), D. Lafon (C2MA, Ecole des Mines Alès), Y. Moënne-Loccoz (Lab. d’Ecologie Microbienne, Univ. Lyon I)

Humidity in caves is most often very high and small temperature changes may induce locally evaporation or condensation on the walls. A current phenomenon observed on these cave walls is the formation of small clusters of heterogeneous materials (clay materials, pigments, calcite, organic material...) that were initially on the wall. The figure to the side is an illustration of this natural process, called vermiculation, which is still not understood. It becomes troublesome when it affects wall paintings. To investigate the vermiculation process, we analyze the interplay between climatology, thin aqueous film formation and clay material cohesion.

Evaporation close to a contact line: modeling and numerical simulation

F. Doumenc, B. Guerrier, V. Janecek
Collaborations : V. Nikolayev (PMMH)
European ITN Multiflow

Evaporation close to a contact line or a meniscus is encountered in many processes (bubble nucleation, coating, heat-pipes etc.) We are developing models and numerical tools to describe hydrodynamics and heat and mass transfer in such processes, taking into account the different scales involved in the flow. The figure (left) shows the stream lines induced by evaporation and substrate motion for a complete wetting configuration.

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Rayleigh-Bénard-Marangoni convection induced by solvent evaporation in a plane layer

F. Doumenc, B. Guerrier
Collaborations : T. Boeck (Univ. Ilmenau, Allemagne), E. Chenier (MSME, Univ. Paris Est), C. Delcarte (LIMSI, CNRS), M. Rossi (IJLRA, UPMC), B.Trouette (MSME, Univ. Paris Est), S.G. Yiantsios (Univ. Thessanoliki, Grèce)

When drying a polymer solution, solvent evaporation induces a decrease of the temperature and the solvent concentration at the surface so that the configuration may become unstable (thermal or solutal Rayleigh-Bénard-Marangoni instability). Theoretical analysis and numerical simulations have been performed to investigate the respective influence of the different mechanisms on convection onset. The figure shows the evolution of the viscosity field during drying.

S.G. Yiortsios, S.K. Serpetsi, F.Doumenc, B.Guerrier IJHMT 89, (2015)
doi: 10.1016/j.ijheatmasstransfer.2015.06.015

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Cisaillement d'un film tombant par un contre-écoulement d'air

N. Kofman, S. Mergui, G. Dietze
Collaborations : C. RUYER-QUIL (LOCIE)

La dynamique des ondes se développant à la surface d'un film liquide tombant est modifiée lorsqu'un contre-écoulement de gaz est imposé à l'interface. Nous analysons expérimentalement le comportement du film soumis à des vitesses de gaz croissante. Nous recherchons les conditions pour lesquelles le train d'ondes rebrousse chemin avant d'être détruit, situation désignée comme étant l'engorgement de notre système. La photo ci-contre illustre un cas pour lequel l'écoulement de gaz génère des structures 3D localisées de grande amplitude et rapides empêchant l'apparition de l'engorgement.