Morphologie of air invasion in an immersed granular layer
Résumé
We report a study of the paths formed by a finite volume of air gently injected at the base of an immersed granular material. A two-dimensional model, based on experimental observations, shows that the typical height and width of the region explored by the branched path depend not only on the injected volume V but also on a dimensionless parameter χ which accounts for the relative effects of the gravity and capillarity: for a given injected volume V , larger gravity effects lead to taller and narrower structures; for a given χ, the typical height and width of the structure scale like V^1/2 and V^1/4, respectively while the typical gaseous fraction in the corresponding region increases accordingly like V^1/4. Such results could be of practical importance: for instance, gas can be trapped on purpose in an underground natural container below a granular slurry. Our results can help in predicting if the gas is likely to reach the free surface and escape the system if the container presents a defect (hole or fracture).
Domaines
Matière Molle [cond-mat.soft]
Origine : Fichiers produits par l'(les) auteur(s)
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