Hello PyLith team,
In the 2D Magma Reservoir example, I noticed that the drained bulk modulus of the crust is set to K_d = 10 GPa, the bulk modulus of the solid grains to K_s = 20 GPa and the Biot coefficient to \alpha = 1. However, since the Biot coefficient is defined as \alpha = 1 - K_d/K_s, I think it should be equal to 0.5 in this case. I’m wondering what value of \alpha PyLith uses in this case?
Thank you!
Internally, PyLith uses
Any extra fields in the auxiliary field are ignored. It looks like the magma-2d example and the information about the poroelasticity auxiliary field need to be updated to match the code.
Does this mean that even if I include permeability, it won’t be used when solving for the solution vector?
Sorry, I missed a couple of lines in the code. The isotropic linear poroelasticity bulk rheology includes isotropic or tensor permeability.
Got it, thank you, this is very helpful!
The way the examples are set up and from what I understand, the Biot modulus M is computed from the porosity \phi, Biot coefficient \alpha, solid grain bulk modulus K_s, and fluid bulk modulus K_f specified in the .cfg as 1/M = (\alpha-\phi)/K_s+\phi/K_f. Since \alpha and M are not independent poroelastic properties, I think it would make sense to similarly compute \alpha internally from the specified K_s and K_d (instead of having to specify it) to make sure the poroelastic properties are consistent. Alternatively, K_s could be computed from the specified \alpha.
We have cleaned up the documentation and code for specification of the material properties for poroelasticity. Refer to the release notes for more information.
Awesome!