Learning Forum

[rickm98]

Hello experts,

in my simulation I have a wall, moving with a constant velocity in x-direction. To do that I wrote a motion profile and put that profile in dynamic mesh (rigid body motion). I use the VOF-method in my simulation, therefore a small timestep-size is needed. After every 5 timesteps i plot the wall velocity and when the timestep size is very small, the wall velocity stays at 0m/s.

[Rob]

If you use the Preview Mesh Motion option does it move?

[rickm98]

If the timestep-size is 9E-4 or bigger then yes. If the timestep-size is smaller then it doesn't move.

[Rob]

One for I'm not aware of any limiters on how large a motion has to be for the solver to see it.

[rickm98]

Little update.
Activating double precision when starting Ansys Fluent fixed the problem.

[Rob]

In other words rounding tolerance on the displacement gave zero motion. thanks for the update, and as a general rule I always run double precision.