[David_C]

Hello All!

I am new to OpenFOAM, and seem to have bitten off more than chew. I would appreciate any help that people have to offer. I would also like to apologize ahead of time, if this question has already been answered. If so, please direct me to the appropriate links!

I am currently working on the mixing of exhaust gases from a rocket and air. This is a compressible case, at a speed of around Mach 2. I have been using rhoSimpleFoam until now, but don't exactly know how to allow for the two different fluids. Obviously, each one has it's own thermodynamic properties.

So my main questions: How do I set up my 0 folder files to allow for two fluids to mix, and which solver should I use for compressible mixing?

Thank you all for your time! I look forward to hearing from you.

- David

[avila.vc]

Hi David, I don't have much experience, but as far as I know, for multiphase flows, the easier to do is to take a look at the multiphase solvers (applications/solvers/multiphase) and tutorials (tutorials/multiphase) like interFoam, compressibleInterfoam, twoPhaseEulerFoam and so on.

[David_C]

Hey avila.vc! Thank you for replying.

Unfortunately, with the multiphase solvers, they are mainly used on incompressible fluids. However, due to the high speed flows of my simulation, I need compressible. The only two that deal with compressibility are cavitatingFoam (obviously dealing with cavitation), and compressibleInterFoam (but this solver is isothermal and immiscible).

So I still need some form of different solver. I was thinking of using rhoSimpleFoam and employing the different chemical files, like reactingFoam. Any thoughts?

[avila.vc]

David, twoPhaseEulerFoam is a compressible solver since ... (I don't really remember the OF version it started as compressible). You should take a look. But with OF3.0.x this solver should be okay for you.


Edit: I should say, however, that I don't know if twoPhaseEulerFoam can manage very high velocities (I have never tested). But unless you have programming experience, I think it is a good starting point. Now, if you still want to modify a solver, I am afraid I am not the best person to help you. But I think implementing more phases is more difficult than making a solver non-isothermal and compressible (like interFoam).
Edit2: Just to be clearer: to modify a solver (allowing more phases to be considered, for example) isn't just put other files in the 0 folder. To do that, you have to modify, in C++, the solver code.