Neighbor Search and calc_force_dem

MFiX How to
#1

Hello MFiX community,

I am attempting to model liquid cohesion forces between particles by modifying the existing van der waals force calculation contained in calc_force_dem.f.

For this to work I will need calc_force_dem to be called when the neighboring particles are not yet in contact. How can I extend the “range” where this subroutine is called?

I have tried monitoring the distance between two colliding particles where the subroutine is called and it seems that it is always first called when the particles are overlapping. Changing the neighbor search parameters does not seem to change this.

Thank you

#2

In the van der Waals cohesion model, there is a cutoff from which the cohesive force applies, called VDW_OUTER_CUTOFF. Maybe you can use the same logic.

#3

Thank you @jeff.dietiker, this was helpful.