using ramp operation for a time dependent moving wall in coupled cfdem

Submitted by malte on Mon, 08/17/2020 - 16:09

Hi,
actually I try to set up a coupled cfdem case. I have a box with one moving wall. The wall velocity has to change with time, so I tried to use the ramp operation for this. Before I start the coupled simulation I fill the box with particles within 50000 timesteps. With constant wall moving everything works fine. My implementation of the ramp operation looks like the following:

variable moveX equal ramp(0,10)
variable moveY equal 0
variable moveZ equal 0
.
.
.
fix move all move/mesh mesh moving_wall linear/variable v_moveX v_moveY v_moveZ
.
.
.
run 0 start 50000 stop 200000

I added the moveX variable to thermo to check if everthing works fine. There I could see, that moveX changes in a loop of 100 timesteps between 0 and 10. Why is it not linear over the timesteps 50000-200000?. The simulation is coupled every 100 iteration.
Maybe there is a better idea than the ramp function?

Regards, Malte!