Hej Quanshu,
I'm currently working on the problem. This extends my research I've done in the last couple years
regarding in solving elasticity (and linear-elastic wave) problems and the diffusion equation separately.
The note given by Thomas are very correct and outline the current research on the problem, but
my approach will solve the problem in one system.
Firstly, good starting points are (for the "flow problem")
- step 20 (stationary diffusion problem with RT-DGQ)
- step 26 (heat equation)
combining both together leads to the well-known instationary diffusion equation, studied and implemented
further (for esp. higher-order time discretisations) in my thesis given here:
A reference code for a distributed-parallel solver of a special lower-order in time cG(1) together with the
outlined MFEM approach for the instationary diffusion equation can be found here:
Regarding the applied space-time discretisation, to documentation is given mostly by my thesis.
Secondly, you must solve the geomechanical problem, which is at least solving the
(quasi-static) elasticity problem. But this is a coupled-problem! cf. the current literature!
In the so-called "fully-coupled" (monolithic) approaches, you need to solve the complete system,
having at least the displacement and the pressure as independent variables together.
Since deal.II does not have to opportunity of solving finite-volume problems, you also need to
add the flux variable of the RT x DGQ approach of step-20 in the sense of step-26 (or meat),
to keep locally the mass conservation.
I prefer to research on a fully DoF system for the displacement, flux and pressure, since this
is easier in my point of view. (Having potentially different triangulations & boundary descriptions
are knocking to my head! Interpolations of different solutions also...)
The first approach of mine in solving the quasi-static Biot's equations will be on the fixed-stress
approach, since I think I have useful iterative solvers for both problems, but the time will show if they are
really useful.
Unfortunately, due to some research restrictions, the newly develop code of mine for the Biot's equations
will not be available soonly under a public release.
Anyhow, if you are willing to share ideas and cooperating in a shared research on the problem
Best
Uwe