Getting started with Finite Elements methods

Question

There is a cubic block of fractured rock; the question is:

• how to simulate fluid flow from top-side to down-side or left-side to right-side?
• Is FEA (FEM,...) the only practical solution?
• If so for the question above in its simplest conditions, that is, flow can happen only through fractures; no interaction between matrix and the fluid; etc etc how to have a quick simulation with FEA?
• Is this practical someone with professionality in FEA could do this in a few minutes? Suppose there is already a suitable mesh generated.
• If not what would you recommend to get started rapidly to be able to solve such simple cases?
• Is there anybody having experience with similar problem (flow modeling); if so what did you use and how did you fulfilled the job?

Note that we are aware of availability of many FEM packages e.g., FEniCS, OpenFoam, ....

Answer 1

There are a number of numerical techniques that could be used to solve this problem, finite elements being probably the most common. If you have a mesh of the fluid flow domain already (presumably the voids/cracks in the rock) it would be very straightforward to set up and run the flow model with pretty much any CFD package (finite element based or not) and most people with any exposure to FEA should be able to do it. I am assuming that you want to understand the fluid flow within the rock in some detail, rather than just evaluate the effects of the rock on the flow in some larger flow domain. In the latter case, there are other approaches which might be more computationally efficient.

Answer 2

Your question refers to simulation of the fluid in the porous medium, e.g. the rock.

I highly recommend using LBM instead of FEM-based methods. LBM simulates the flow in porous media by nature. Phys Review E contains publications about that approach. What is even more attractive, LBM can be also easily parallelized on GPU.

Answer 3

You could use the one-dimensional form of Darcy's Law.