Define Mixing Index of Multi-phase gas-solid flow
 

Dear All;

Can anybody guide me through the setup of a user-defined function for calculation of the mesoscopic mixing index of gas-solid flow in fluent;

mesoscopic mixing index: define mixing status (mixed/not mixed) based on the volume fraction of solids in the computational cell

if(vof_s1 > 0.01) /* vof_si : volume fraction of solid i */
{
Nt = Nt + 1;
if (abs(vof_s1 - vof_s2)/vof_s1 < 0.1) {Ni = Ni +1;}
MI= Ni/Nt;
}

I want to access the void fraction in each cell for every phase and calculated MI and then posting its value after each time step