Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

Non-Newtonian effects in simple models of mantle convection

H.-B. Mühlhausa,b,*, M. Daviesa, L. Grossa, L. Moresic
aESSCC, The University of Queensland, St Lucia QLD 4072, Australia bCSIRO Division of Exploration and Mining, 26 Dick Perry Ave, Kensington WA 6051, Australia cSchool of Mathematical Sciences, Building 28, Monash University, VIC 3800, Australia

  Full Text
One of the difficulties with self consistent plate-mantle models capturing multiple physical features, such as elasticity, non-Newtonian flow properties, and temperature dependence, is that the individual behaviours cannot be considered in isolation. For instance, if a viscous mantle convection model is generalized idealistically to include hypo-elasticity, then problems based on Earth-like Rayleigh numbers exhibit almost insurmountable numerical stability issues due to spurious softening associated with the co-rotational stress terms. These difficulties can be avoided if a stress limiter is introduced in the form of a power law rheology or yield criterion. A general Eulerian model is discussed and it is shown that the basic convection modes of a cooling planet are reproduced.

Keywords:  Mantle convection; Non-Newtonian flow; Stress rate; Episodicity; Visco-elastic-plastic deformation; Numerical stability

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