Adhesion between particles and walls

Hi,

I am wondering how the adhesion between the particles and the wall is treated. I have set up my simulation with 3 different types, 1 is the particles, 2 is the walls, and 3 is for a no friction/no adhesion symmetry plane. I have specified the cohesion as:

fix m6 all property/global cohesionEnergyDensity peratomtypepair 3 &
1000000 1000000 0000001 &
1000000 0000001 0000001 &
0000001 0000001 0000001

I have set up a simple little test model that forces a batch of particles against a stationary (closed) gate via a conveyor. I am moitoring the force on the gate. I would have expected the force to surpass the friction force. In this model, I dump ~210 kg, the friction is 0.8 between the conveyor (type 2) and the particles (type 1). So if the cohesion is off, I expect the force on the gate to be ~1648 N, which it is essentially.

I expect that the wall force in my model would increase as I increase the cohesion between type 2 and 1. But it does not seem to increase as I would have expected. Maybe the magnitude of my cohesionEnergyDensity is not appropriate? Does anyone have a technical reference explaining cohesion as it is implemented in LIGGGHTS?

All my model files are included.

Thanks for any help.

Thank you,

Kirk