Hello All, I have a question on fix move rotate command in LIGGGHTS. Setup has a drum made up of particles, closely placed so that there is no gap.
I'm first using
fix wall particleWall freeze to freeze particles and then using
fix particleWallRotate particleWall move rotate 0.0 0.0 0.0 0.0 0.0 1.0 0.05 to rotate wall with a constant period of 0.05 sec.
This is working okay.
But when I'm trying to accelerate rotation using a time-dependent variable using
variable PERIOD equal 60.0/(400.0+5.0*time)
fix particleWallRotate particleWall move rotate 0.0 0.0 0.0 0.0 0.0 1.0 v_PERIOD
Simulation fails with following error: ERROR: Expected floating point parameter in input script or data file (../fix_move.cpp:144)
1. Is fix freeze must before fix move rotate?
2. How can rotation be accelerated for this wall made up of particles?