[fcollonv]

Dear foamers,

I'm trying to do the simulation used by Weller et al. to validate XiFoam
[H.G. Weller et al., 1998, Application of a Flame-Wrinkling LES Combustion Model to a Turbulent Mixing Layer, Twenty-Seventh Symposium (International) on Combustion/The Combustion Institute].

For that first I took simply the tutorial case, refine a bit the mesh at the shear layer and boundary layers and update the U and k file to use the experimental profiles.
Then the flame was effectively wrinkled (see XiFoamInit.jpg VS WellerResults.jpg - on the last the top picture is from the experiment). But the temperature and the pressure were crazy. In XiFoamInitTemperature.jpg I use a threshold filter to select the cells with a temperature between 260K and 290K. That range is totally unphysical as the temperature should not go below 293K.
So I changed the numerical schemes (cf. attachment). And now the pressure and the temperature are great: p is roughly constant and the minimal temperature is 292.6 K However the instability of the flame is gone.

Any suggestions will be appreciate.
Thanks,

Frederic

Additional information about the simulation:
* max CFL = 0.5
* no gravitation
* the mesh is not has large in the homogeneous direction as in the Weller's paper. The dimensions are those of the tutorial case
* the combustion properties are those of the tutorial case
* it looks like the wrong smaller temperature was triggering the instabilities due to a bigger density difference between the fresh gas and the burnt one.