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[Jan Stránský <question220640@xxxxxxxxxxxxxxxxxxxxx>]

Question #220640 on Yade changed:
https://answers.launchpad.net/yade/+question/220640

    Status: Open => Answered

Jan Stránský proposed the following answer:
I see now that constant velocity would not produce expected results :-) The
ideal solution would be to use facets with mass, but I have no experience
in this..

I personally would do something like this ("manual" time integration of
chosen particles):

O.engines = [
  ...
  PyRunner(iterperiod=1, command="moveFacets()" )
]

vel = Vector3(0,0,1) # initial velocity
actingForce = -10
def moveFacets():
  reaction = sum(O.forces.f(facet.id) for facet in facetsToMove) # total
force acting on movable facets from interaction with otehr particles
  force = actingForce - reaction[2]
  accel = force] / mass # z cmoponent of acceleration, mass is some
artificial constant
  vel[2] += accel*O.dt # some kind of time integration
  for facet in facetsToMove:
    facet.state.vel = vel

Jan



2013/1/31 daalgi <question220640@xxxxxxxxxxxxxxxxxxxxx>

> Question #220640 on Yade changed:
> https://answers.launchpad.net/yade/+question/220640
>
>     Status: Answered => Open
>
> daalgi is still having a problem:
> Hi Jan! Thank you for replying so fast.
>
> I'm sorry I didn't mention it, but the boundary conditions are already
> established: a box with no upper wall. So yes, I already have the
> simulation, but I need to apply the corresponding load cases.
>
> At the first load case, since I should apply a force just in a certain
> area (let's say a quarter of the total area) I think the moving facet
> wouldn't produce the expected effect. Maybe I could identify the
> particles in contact with the loading area and then prescribing a
> velocity to them every time the load is applied. Also, to simulate the
> stirring bar (load case 2) I could do something similar, identify the
> appropiate particles and set a velocity to them. I haven't though much
> about it, do you think it'd be correct?
>
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