Problem, adding passive scalar transport for turbulent, compressible flow
I'm currently trying to implement passive salar transport for visualization of concentrations in my turbulent, compressible jet in crossflow simulation with rhoCentralFoam and the komegaSST model.
I read a lot about passive scalar transport for incompressible cases and also for turbulent cases, but it is the compressible thing that makes me a headake... :-/
I implemented alphaNEqn.H with alphaN, being the dimensionless concentration as follows:
Obviously, the units of the unsteady and convective term on the left do not correspont to the units of the diffusion term on the right. I think that rho has to be added to the diffusion term aswell, but I don't know how to do that.
Dividing the whole equation by rho is also not possible, because it is compressible.
So... does anybody have an idea, what I should do in this case?
By the way... DalphaN is computed using
Thanks in advance...
After some trys, I realized that adding rho to the diffusive term like here
Can anybody say something about that?
In addition, the now calculated alphaN, which is initialized as 1 in the jet flow and 0 in the crossflow increases slightly above 1 (< 1.09) in regions of high density gradients and in other regions it also decreases slightly below 0 (> 0.9999). That should not be possible for how I wanted alphaN to be.
Does anybody know why that happens? The overall picture of the alphaN field looks allright. Could the mesh be the problem? It is still pretty coarse for testing reasons. Or should I devide alphaNEqn by density though?
Thanks it worked for me too :)
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