yade-users team mailing list archive

[Anton Gladky <gladky.anton@xxxxxxxxx>]

Seems, your task is possible to solve in YADE. At least the most part of it.

Your magnetic forces can be read from the file with python interface. You
can do it and with C++, but I think Python is better for that.

Those magnetic forces can be applied or with "gravityEngine" or with
"ForceEngine". If it is not suitable for you, you can relatively easy add
your own engine. The main is to describe mathematically your task. For "Drag
force" you definitely need your own engine.

Difficult shapes can be imported form stl or mesh-files, whatever you want.

Cluster implementation can be the most difficult problem. YADE is not using
mpi-protocol. For now YADE can more-less normally handle about 10^5 elements
on modern 4-core machines.
As I remember, Vaclav tried it on 8-core machine with good results. Right?

Have a luck! If you have any questions, we will try to help.
______________________________


Anton Gladkyy


2010/3/7 Peiying Hsieh <peiying2006@xxxxxxxxx>

> Hi, Anton,
>
> The reason why I am interested in the rod_penetration example is because I
> want to learn how to import stl geometries into yade.  It looks like quite a
> lot has been changed since 0.20-2.
>
> The case I am interested in solving is the following:
>
> a cup, 3mm X 12 mm X 40 mm, contains about 50 % of liquid.  In the liquid,
> there are about 1 million para-magnetic particles (1 micro in diameter).
> At time = 0, the para-magnetic particles are randomly distributed in
> liquid.  Then, a permanent magnet is placed next to the cup.  Hence, the
> magnetic field starts to attract the particles toward the cup wall.  I would
> like to know how long it takes to attract all particles to the wall.  The
> cup geometry is not a simple box of cylinder.  So, I need to import the cup
> geometry in stl format.
>
> I have already calculated the magnetic field (flux and also magnetic force
> field) using a finite element PDE solver, called getDP.  The magnetic field
> is static, not time dependent. Because the particles are para-magnetic, it
> can be assumed that the magnetic force is like external body acting on the
> particles, like gravity, except that the magnetic force field varies with
> space.
>
> Is it possible to read the magnetic force calculated outside of yade into
> yade?  How to apply the force on the particles?  Because the magnetic force
> varies with space, the force on each particle has to find out from the nodes
> (or cells) where the magnetic force was calculated.
>
> How to apply drag force on the particles?  Drag force varies with speed of
> the particles.
>
> If the problem above is achieved, then, I would like to extend to next
> step:
>
> After all particles has been attracted at the cup wall, a small tube comes
> down to near the bottom of the cup, turn on vacuum to "suck" all liquid
> inside the cup out.  I would like to know if the magnetic force is strong
> enough to hold the particles in place.  This will involve coupling yade with
> OpenFOAM (free surface with surface tension effect).  If this is done, I
> will image that, it has to be done on a cluster because this has to be very
> calculation intensive.
>
> Pei-Ying
>
>
> On Sun, Mar 7, 2010 at 7:28 AM, Anton Gladky <gladky.anton@xxxxxxxxx>wrote:
>
>> You can find a lot of examples in ./scripts and ./scripts/test
>> directories.
>> As Sergei told, some of them are outdated.
>>
>> I personally try to keep updated regular-sphere-pack.py example. Hope it
>> will be useful for you.
>>
>> What kind of tasks you are planning to solve?
>> ______________________________
>>
>> Anton Gladkyy
>>
>>
>> 2010/3/7 Peiying Hsieh <peiying2006@xxxxxxxxx>
>>
>> Thanks Sergei!
>>>
>>> Are there any websites where I can find some more examples?  At this
>>> point, I have no clue how yade works, so, it will be helpful for me to run
>>> some more examples.
>>>
>>> Best,
>>>
>>> Pei-Ying
>>>
>>>
>>> On Sat, Mar 6, 2010 at 10:35 PM, Sergei D. <sj2001@xxxxxxxxx> wrote:
>>>
>>>>
>>>> >
>>>> > I would like to run the examples in the examples folder.  So, I
>>>> entered the
>>>> > rod_penetration folder and typed:
>>>> >
>>>> > yade-trunk model.py
>>>> >
>>>> > but, got errors below.  What could be the reasons of the error?
>>>> >
>>>> > What is the proper way to run the examples?
>>>> >
>>>>
>>>> You way is proper, but many examples is outdated and need to be updated
>>>> of syntax.
>>>>
>>>>
>>>> --
>>>> Best regards,
>>>> Sergei D.
>>>>
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>>>
>>>
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>>
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>