Séminaire ISTerre

Pore-scale mushy layer modelling

jeudi 20 février 2025 - 11h00
Sam Butler - University of Saskatchewan
--- 
Mushy layers are multicomponent porous media where the matrix and interstitial fluids can exchange both heat and mass. They are found in nature in sea-ice, magma chambers, possibly at Earth’s inner-core-outer-core boundary and during the early solidification of magma oceans. Passive (nonmushy) porous media exhibit a rich range of behaviour because of the different diffusion and advection rates of solute and heat. In mushy layers, the dynamics are made even more interesting by the coupling of solute concentration and temperature by freezing and melting. There has been a great deal of theoretical work on mushy layers using “ideal” mushy layer equations where the liquid and solid are assumed to be in perfect local thermodynamic equilibrium and are treated as a single continuum. In order for the liquid to remain in thermodynamic equilibrium with the matrix, there must be a separation of timescales between those for diffusion at the pore-scale and advective transport at the system scale. The range of validity of the ideal mushy layer equations has not previously been carefully examined. In passive porous media, pore scale modeling is now used to examine assumptions made in treating the solid and liquid as a single continuum. In this talk, I will first review the transport of heat and solute in passive porous layers and then show some interesting effects in mushy layers – such as the fact that the introduction of a hot fluid can induce freezing and a cold fluid can induce melting. I will then introduce a model of the simplest possible pore-scale mushy layer which consists of a cylindrical fluid region surrounded by a solid annulus where heat and mass can be exchanged at the pore wall. Using the pore-scale model, I will verify some predictions of ideal mushy layer theory regarding transport rates. I will additionally show that there is a threshold, appropriately defined, Peclet number below which ideal mushy layer theory remains valid. Applying this criterion to natural and laboratory analog systems shows that in some extreme cases, the mushy systems may have not been entirely ideal.

Equipe organisatrice : Grands Séminaires ISTerre

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Informations de visio :

https://univ-grenoble-alpes-fr.zoom.us/j/91894734867?pwd=9Cyb3OEX4fJOX2Ce6ExI7lqlrWrhyG.1

“Minimalist seismology”: studying earthquakes with sparse instrumentation

jeudi 17 septembre 2026 - 11h00

Mathieu Causse - ISTerre

Equipe organisatrice : Organisation labo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

Stable‑to‑dynamic expansion of fault slipping area through fluid injection observed in laboratory experiments using a sub‑meter scale specimen

vendredi 18 septembre 2026 - 14h00

Takatoshi Ito  - Université de Tohoku, Japan

Equipe organisatrice : Mécanique des failles

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

Tectonics, Mantle Dynamics and Coupled Lithosphere-Mantle-Core Evolution of Earth and Other Rocky Worlds

jeudi 24 septembre 2026 - 11h00

Paul Tackley - ETH Zurich

Equipe organisatrice : Grands Séminaires ISTerre

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

Tectonics, Mantle Dynamics and Coupled Lithosphere-Mantle-Core Evolution of Earth and Other Rocky Worlds

jeudi 24 septembre 2026 - 11h00

Paul Tackley - ETH Zurich

Equipe organisatrice : Grands Séminaires ISTerre

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

Apport des expériences analogiques pour la modélisation et le suivi en temps réel de la propagation du magma en profondeur : Exemple du Rift Est Africain

jeudi 1er octobre 2026 - 11h00

Virginie Pinel - ISTerre

Equipe organisatrice : Organisation labo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

A t-on encore besoin de plaques pour expliquer la tectonique de la vallée du Rhône et des Alpes Occidentales ?

vendredi 2 octobre 2026 - 11h00

philippe VERNANT - Geosciences Montpellier

Equipe organisatrice : Tectonique active et sismicité

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

TBA

vendredi 2 octobre 2026 - 14h00

Hugo Boulze - 

Equipe organisatrice : Cycle sismique et déformations transitoires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

TBA

vendredi 9 octobre 2026 - 11h00

Eric Beaucé - ISTerre

Equipe organisatrice : Cycle sismique et déformations transitoires

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite

TBA

vendredi 20 novembre 2026 - 11h00

Farzaneh Mohammadi - ENS Paris

Equipe organisatrice : Cycle sismique et déformations transitoires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Lire la suite