One of the foremost challenging topics that has found wide applicability deals with the flow in porous media. The topic has been, time and again, researched with great interest. I have done my share of flow simulations involving porous media and, uptodate, havent figured out "one particular" global model that can be used in a universal manner. It is understandable to assume that every single porous media flow is different and the complexities associated with the interactions within the systems are not easily resolved..Still, to me, using different models for different systems and not able to combine them all together indicates that the fundamental research in this area needs serious revision.
Information on multi scale modelling in porous media can be obtained here http://www.porous-media.org/
A nice handout on porous media here: http://www.columbia.edu/~rl268/ChESite/E3110/Handout_15.pdf
Texas A&M has a nice list of publication reports involving different simulation analysis.
Bad that they did not name files easy to open and read as per need. Sample file on porous media: http://isc.tamu.edu/publications-reports/tr/9706.pdf
Another nice website with several papers/documents/files on porous media flows can be found here: http://www.win.tue.nl/macsi-net/Events/
One of Prof. Joseph's page with several papers on cavitation and fundamental fluid dynamics, also has some papers on porous media
(see http://www.aem.umn.edu/people/faculty/joseph/papers/) - the paper is modeling foamy flow in porous media (http://www.aem.umn.edu/people/faculty/joseph/papers/foamyOils3.pdf)
a nice paper for definite reference and further research http://library.wrds.uwyo.edu/wrp/85-37/85-37.pdf
Several softwares are now adept in carrying out flows through porous mediums. ANSYS,STAR,Flow3D,FIRE,openFoam(:),Polyflow(?) - all have a variety of models in-built. Again, directions of usage is based on particular application where the terms involved in the transport equations will be treated appropriately. Based on my experience in coding porous flows, fundamental changes (the GUI in softwares) let you do is to adjust the pressure gradient (based on some interactions) and the drag coefficients. As written in my earlier blog, drag coefficients play a pivotal role in producing excellent convergence and stability rates owing to the nature of the set up of the solution matrix.
A sample FLOW3D movie (Finite Volume method) - Read Flow3D paper on flow through unsaturated porous media here: http://www.flow3d.com/pdfs/tn/FloSci-TN25R.pdf
Youtube video: http://www.youtube.com/watch?v=jszmSsF2gDI
Get more flow3D based runs here: http://wn.com/Modeling_Porous_Media_with_FLOW-3D
Doing porous media flows using Lattice boltzmann !!
I found the following site - http://www.engr.ucr.edu/~vafai/Publications/ very useful. They have a long list of papers on heat and mass transfer with a lot of publications/book chapters on porous media flows.
Modeling and simulating your own porous media flow is now possible - thanks to openFoam !! A sample modeling capability detail is presented here
I followed this researcher : http://www.ifd.mavt.ethz.ch/people/hajibeygi/index with some nice information in the site.
There are loads of papers on multiphase flow modeling in Heterogenous porous media, porous medium flows with fractional distillations, fractured media - with and without turbulence - how complicated can these get??