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Convection thermique dans un fluide visqueux hétérogène : phénoménologie, lois d'échelle et applications aux systèmes terrestres

Abstract : The Earth's mantle is heterogeneous but the characteristics of its reservoirs are not constrained. We have thus studied a simple system, where two miscible fluids with different densities and viscosities are subjected to a destabilizing temperature contrast. At low buoyancy number B (ratio of the stabilizing chemical to the destabilizing thermal density anomalies), convection develops over the whole tank depth; when B is large, the two layers convect separately. In both cases, mixing progressively takes place, but numerous transient behaviors are possible. Of particular interest is the pulsatory dynamics, where the interface deforms in large domes moving up and down quasi-periodically. In the Earth, our analogical model suggests an evolution from a `two-layered' model towards a `one-layer' model. A pulsatory dynamics provide a simple explanation for the long-term episodicity in planetary interiors.
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https://tel.archives-ouvertes.fr/tel-00002530
Contributor : Michael Le Bars <>
Submitted on : Tuesday, March 11, 2003 - 3:36:49 PM
Last modification on : Friday, March 27, 2020 - 3:40:33 AM
Long-term archiving on: : Friday, April 2, 2010 - 6:25:05 PM

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Michael Le Bars. Convection thermique dans un fluide visqueux hétérogène : phénoménologie, lois d'échelle et applications aux systèmes terrestres. Géologie appliquée. Institut de physique du globe de paris - IPGP, 2003. Français. ⟨tel-00002530⟩

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