[Carmelo98]

Thank you, indeed I can see some diffusion.
I tried also the case of two gases at different temperature. Also in this case, diffusion occurs.
I compared results obtained with reactingFoam and rhoCentralFoam for temperature diffusion:

1) For very high viscosity, both simulations give same results;
2) For real viscosity values, diffusion is much more faster in rhoCentralFoam.
I have to invastigate further and compare numerical results with analytical solutions.
I don't know if anyone else has encountered these strange behaviors of the solvers.
Thank you

[Carmelo98]

Originally Posted by Carmelo98

Thank you, indeed I can see some diffusion.
I tried also the case of two gases at different temperature. Also in this case, diffusion occurs.
I compared results obtained with reactingFoam and rhoCentralFoam for temperature diffusion:

1) For very high viscosity, both simulations give same results;
2) For real viscosity values, diffusion is much more faster in rhoCentralFoam.
I have to invastigate further and compare numerical results with analytical solutions.
I don't know if anyone else has encountered these strange behaviors of the solvers.
Thank you

I run more simulations and I got very strange (and wrong) results.
First of all, reactingFoam seems to work well.

The problem is with rhoCentralFoam.
If I set viscosity:


I got these results:

1. if I use a coarse mesh () small diffusion occurs for a time simulation of 1(sec)
2. If I use a fine mesh (), for a time simulation of 1 (sec) results are completely wrong

I have attached files of these two cases, so that anyone can easily check what I'm saying.
https://we.tl/t-C0GA4p2ap3

It's really strange beacuse for inviscid flow, rhoCentralFoam should directly avoid to solve Navier-Stokes equations.
Thank you