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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:

M. Ishimura (PhD), N. Sgreva (PhD)

Former Members:

D. Brand (PhD, 2016), M. Dey (PostDoc, 2015), P. Freydier (PostDoc, 2019), G. Gerardi (PhD, 2018), Y. Li (PostDoc, 2018), A. Salvador (PhD, 2018), A. Sibrant (PostDoc, 2017), E. Sultan (TA, 2016), B. Xu (PhD, 2016), M. Zhou (Visiteur, 2019)

Scalar transport within a wavy falling liquid film

G. Dietze

Collaborations : C. Ruyer-Quil (USMB, Chambéry), M. Ishimura et S. Mergui (FAST)

Within the ANR project wavyFILM, we study falling liquid films producing solitary surface waves due to interfacial instability. Wall corrugations allow to enhance convective transport within these waves and thus to intensify heat/mass transfer across the liquid-gas interface. The numerical simulations on the left, which were performed with the solver Gerris, demonstrate the effect of different corrugation types on the field of a passive scalar governed by a convection-diffusion equation in the liquid. In these cases, the Péclet number is high, so transport is convection dominated. Corrugations increase the averaged transfer coefficient by 30%.

G. F. Dietze J. Fluid Mech. 859, 1098 (2019)

Heat transfer in karstic massifs

F. Doumenc, B. Guerrier, S. Mergui
Collaborations : P.Y. Jeannin (ISSKA, Suisse)

Karstic massifs are complex geological structures, containing networks of underground rivers, caves and conduits. Caves represent fragile ecosystems where biogeochemical processes largely depend on cave temperature. Caves also host unique environmental records whose interpretation closely depends on temperature as well. It is therefore important to identify the spatial and temporal evolution of the temperature field according to the massif morphology and to the climatic conditions. The figure on the left is a numerical simulation illustrating at a given time the thermal disturbance induced by the presence of a shallow cave (about ten meters below the surface) in a limestone massif.

B. Guerrier et al. Int. J. Therm. Sci. 146, (2019)

Evaporation close to a contact line: modeling and numerical simulation

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

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.

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).

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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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Vermiculation in caves

F. Doumenc, P. Freydier, B. Guerrier, J.-P. Hulin, J. Martin, S. Mergui
Collaborations : P.Y. Jeannin (ISSKA, Suisse), Y. Moënne-Loccoz (Lab. d’Ecologie Microbienne, Univ. Lyon I)

The picture on the left shows the rock wall of a cave with vermiculations (black worm-shaped in the picture). This phenomenon is frequently observed in underground environments and corresponds to the spontaneous formation of aggregates of materials initially present on the walls (clays, calcite, organic matter, etc). This phenomenon might become an issue in a painted cave because it can move the pigments and therefore damage the paintings. The purpose of this study is to understand the mechanisms responsible for the loss of cohesion of the material on the wall, with the aim of improving the preservation of prehistoric painted caves.

P. Freydier et al. Rheologica Acta 58, (2019)

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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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)

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)