Mesh is moving faster than expected

Submitted by fabregas04 on Fri, 05/25/2018 - 09:29

Hi guys,

I use the move/mesh command to move mesh linearly along the z-direction.
I'm using the SI unit system. I set the velocity as 0.05 mm/s for the mesh.
fix meshmove all move/mesh mesh Cad1 linear 0 0 -0.00005
And my timestep is 0.00001

But after I check the result it moves way much faster.

I don't know how it happened.

Help me please.

richti83's picture

richti83 | Mon, 05/28/2018 - 08:08

Did you included the dumpstep in your calculation ?
t=dumpstep*dt and than v=dx/dt ?

You can dump the curent velocity of a moving mesh with dump-style mesh/vtk and keyword vel

mesh/vtk args = zero or more keyword/ value pairs followed by one or more dump-identifiers followed by one or more mesh ids
keywords = output
output values = 'face' or 'interpolate' or 'original'
dump-identifier = 'stress' or 'id' or 'wear' or 'vel' or 'stresscomponents' or 'owner' or 'area' or 'aedges' or 'acorners' or 'nneigs'

https://www.cfdem.com/media/DEM/docu/dump.html

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fabregas04 | Tue, 05/29/2018 - 11:24

Yes when I calculate the distance of the mesh, I used the same formula you wrote.
And thanks for the velocity information. I'll use this command and then see what happens.
Thanks a lot!