Densitybased, fullycoupled, compressible solver in OpenFOAM?
Dear all,
I would like to discuss and to share opinions with all you Foamers out there about the lack of a densitybased, fully coupled, compressible solver in OpenFOAM. I've been studying OpenFOAM for about a month and, as far as I have understood, the only densitybased solver (by "densitybased" I mean that density is calculated from continuity equation) is rhoCentralFoam, which however solves the governing equations separately one from each other (in a socalled segregated way). All the other solvers are of pressurebased type. First of all: is this true? Second: how hard do you think it would be to create a new densitybased solver, which solves the governing equations simultaneously (i.e. a coupled solver), provided with a robust upwindlike scheme such as Roe's or AUSM? Third: I have found, searching the Forum, that few years ago two Italian students developed a solver called aeroFoam http://www.cfdonline.com/Forums/ope...aerofoam.html which apparently satisfies all the features that I mentioned. However, the solver has not been officially included into one of the OpenFOAM releases and the project has been apparently abandoned. Natural question: why? :D Hope the discussion will be constructive, Francesco 
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In addition, the rest of OpenFOAM would be need to made of aware of these new classes, e.g. the linear solvers. There has been some ongoing development in the extend branch of OpenFOAM to add block coupled matrix classes. I don't believe a coupled NS stokes solver has been built yet with it but I have seen work that uses it to couple other quantities. Dig around the last couple of workshops for material. So as you can imagine, the work is significant and nontrivial. 
Dear Chris,
thanks for your answer. I realize the strong effort needed to extend OpenFOAM towards a coupled strategy. For those interested, the subject is studied in more detail in the following slides: http://www.openfoamworkshop.org/6th_...ord_slides.pdf On the other hand, I think that implementing an upwindlike flux scheme in rhoCentralFoam, for instance, should be much easier. Any experience/opinion? 
One other effort of note is some densitybased (segregated) solvers which include some more modern convective schemes, e.g. AUSM, etc, for turbomachinery in the extend repo:
http://openfoamextend.git.sourcefor...urbo;a=summary I have seen very little documentation about it's use (presentatations or otherwise) but it's there for you to explore. 
Very interesting, thank you very much!

recently I transplant it to OpenFOAM 4.1. You can check it at https://github.com/chengdi123000/AeroFoamV12008.
as Chris Sideroff pointed out, foamextend implemented block Matrix function. However, they did not offer how to implement block coupled solver. 
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