[Jasper Z]

Dear Foamers,

I am compiling a Eulerian-Eulerian-Lagrangian solver in OpenFOAM. But I faced a problem when implementing the Gidaspow drag model between fluid phase (air or water) and solid phase.
The equation of the drag coefficient is shown below, where phik is the volume fraction of the air or water phase. I noticed that phik is on the denominator, so when the fluid (air or water) phase volume fraction is pretty small, betak tends to be infinity, and this equation cannot be solved with a floating point exception.

I was wondering how I can fix this issue during the implementation of this equation? Do I need some special treatments (e.g., make phik larger than 0.1 or something like this)? Please give me some hints! Appreciate!

Jasper