[mshehata85]

Dear Foamers,

My question is regarding the "phasePressureCoeffs" usually specified in the turbulenceProperties.particle file in OpenFoam (for example in the fluidized bed twoPhaseEulerFoam tutorial)

I have done an extensive online research and I concluded it is a way to compute the derivative of inter-particle stress w.r.t volume fraction in an attempt to avoid exceeding the specified maximum volume fraction.

However, I do not really understand the purpose of it as I thought that the "frictionalStressModel" is the one responsible to avoid the over-packing by incorporating the frictional component after exceeding the specified threshold.

So my questions are:

1- Why and when I need to activate the phase pressure model (by setting g0 to a positive value)? is there any practical reason to activate it?

2- Does anybody know the reference to this exponential model? No reference is available in the " phasePressureModel.H" or any where else on the documentation.

3- is the default parameters ( g0, preAlphaExp, expMax, and alphaMax) valid for all two-phase cases. if not, how to estimate these parameters? Do they affect the resulting accuracy?

4- Why "alphaMax" is specified twice in the same file, once in the "kineticTheoryCoeffs" and another time in the "PhasePressureCoeffs"? I thought both of them refer to the same criteria!!!

I appreciate any help because I have been looking for an answer for more than 4 months. So, this Forum is my last resort.

Best Regards.

Mahmoud