yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxxxxxx>]

Good point. I think you can consider that the max value of dimensionless
Pc is the same (at least the order of magnitude) for all possible distances.
When you know this maximum for particles in contact (how much is it by
the way?) it applies for the other interactions as well.
It is indeed less easy to detect problems algorithmicaly for this case,
but practically you will get warned as soon as two particles are in
contact, which will occur in most cases.
As a general rule: if you manipulate saturation degrees of the order of
10e-6 or so, it should ring a bell.

Bruno


On 07/11/14 16:59, Jerome Duriez wrote:
> Hi, I'm coming back on capillary files. So we faced last time
> situations where considered Laplace solutions were "wrong": because a
> zero volume meniscus was computed for contacting spheres. Which is
> finally no-sense.
>
> This error might be easy to spot, especially with the LOG_ERROR you,
> Bruno, wrote in the code.
>
> But... Now I wonder if other cases might lead to non-sense results ?
> This last error concerned contacting spheres: case D =0 (or
> adimensionned D* = 0) and is easy to spot for this reason.
> Could such problem appear for non-contacting spheres ? (yes, probably
> ?) How to spot there is an error in this case ?
>
> Maybe there is no solution in the current state of the code / data
> files, but any remark is welcome.
>
> Jerome
>
>
>
>
> ------------------------------------------------------------------------
> *From:* Yade-dev
> [yade-dev-bounces+jerome.duriez=ucalgary.ca@xxxxxxxxxxxxxxxxxxx] on
> behalf of Bruno Chareyre [bruno.chareyre@xxxxxxxxxxxxxxx]
> *Sent:* October-30-14 8:54 AM
> *To:* yade-dev@xxxxxxxxxxxxxxxxxxx
> *Subject:* Re: [Yade-dev] Some cleaning in capillary law
>
> On 29/10/14 22:37, Jerome Duriez wrote:
>> Ah, this is a clarification... I knew this was succion value
>> dependant, but did not catch that the zero volume is inconsistent...
>> Then, would it possible to know a validity range of the capillary
>> data files ?
>>
> Only trial and error can tell at this point. Keep in mind that the max
> value is defined in terms of non-dimensional pressure pR/gamma (p:
> succion, R: radius, gamma: surface tension), not in terms of p.
> I must say I'm not in a hurry to fix those things since we are in the
> process to introduce another capillary model which will deprecate this
> one (the work of Caroline Chalak).
>
>> A second thing is that I was thinking to commit, with the reverted
>> fCap, the use of alpha * -currentContactGeometry->penetrationDepth
>> for D value (instead of computation of l. 112, (*) ).
>> It would be equivalent to current computation, and maybe useful for
>> periodic simulations. I'm currently using it (mainly for non-periodic
>> cases, yet)
>>
> Yes, it makes no sense to compute penetration again, as suggested in
> the code comment.
> You are welcome to change this.
>
> B
>
>
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-- 
_______________
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
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38041 Grenoble cedex 9
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