I am working on a model for plate-mantle interaction (small-scale convection) and associated melt production. I’d like to do 3D regional upper mantle models over ~100 Myr time span, so tracking melt in a 2-phase flow model is probably too slow, and also not really needed, as I am mostly interested in where melt forms, and roughly how much. The approach to tracking melt and associated latent heat effects as described in Gassmoeller et al., 2016, https://doi.org/10.1002/2015GC006177, seems to me just the kind of complexity that seems right for this model. I have a few questions related to this:
Which is the best material model to set this up? I have mainly been using the ‘Visco plastic’ material model for different geodynamic models, and already built a model for this project using this material model as well: I would like to explore the effects of composite rheology, and perhaps other rheological features, and would also like to use multiple compositions with their own material properties, so this material model is quite suitable in that respect. But at the moment, the melting part is really too simple: I only calculate melting using the available parameterised melting postprocessor, so cannot incorporate any feedback of this melting (e.g. latent heating). I could adapt the material model to incorporate the melt calculation inside it, include the latent heat effect as a heat source, and track the depletion to affect the solidus temperature (as done in Gassmoeller et al. (2016)), but I wonder if this is the best way forward. Should I switch to another material model, and if so, is there one that has (some of) these features already incorporated?
This material model choice relates to another question: the ‘Visco plastic’ model is incompressible. Given the sensitivity of melting to the ambient mantle temperature, incorporating latent heat of melting would be essential, and including adiabatic heating and viscous heating should then probably also be included. But how internally consistent would that be if the model is incompressible? Such model would probably amount to the ‘Extended Boussinesq Approximation’. But given that ASPECT has several compressible material options, would it be more appropriate to use one of those instead? I think I would prefer to stick to an incompressible model, but only if that is still ‘acceptable’ in combination with the different heating terms.
Are any examples available to look at for any of the above?
Many thanks for any support, advice or thoughts.