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[Jerome Duriez <Jerome.Duriez@xxxxxxxxxxx>]

Hi,

I take advantage of Christian's recent commit (*) to re-discuss a little this validity range of capillary files. In the end, I see only one validity issue that comes from the precision with which the maximum suction value (the one above which there is no more solution for Laplace's equation) could be approximated during the construction of this files.

E.g. for contacting monosized spheres the maximum succion value was found indeed to be 1493 (~ the 1500 value that was previously spotted by trial and error) : see l. 686 of M(r=1) file, (suction is the second column).... Whereas for contacting spheres with r=2, it has been found as 2849 (see l.616 of M(r=2) file..)
This corresponds in both cases to smallest filling angle values around 2 degrees (two last columns), whereas probably the theoretical maximum value of suction here is infinite, and the theoretical minimum filling angle should be 0.

If I am right, I guess the same issue arises for non contacting spheres. For monosized spheres at an adimensionned distance of 0.1, the maximum suction value in the capillary file is 8.7, corresponding to a lowest filling angle value of 10.6 deg (l. 12876 of M(r=1) file...). I guess these values only approximate the exact limit values of maximum suction and minimum filling angle, but the exact suction limit value is probably far from 1500 in this distant case.


Do you share my understanding ?

If yes, there would be only one problem in our simulations : that the code can not handle correctly the cases (existing in reality) falling between the maximum suction value written in the files (that depends on the radii ratio and distance), and the exact maximum suction value. Is it really a big deal ?
(If not, it is finally maybe not catastrophic to run simulations with uc* > e.g. 1500, and Christian was right to lower the "noise" of the error message)

Jerome

(*) https://github.com/yade/trunk/commit/569aa859ab7e9ca8e9ac1a99b445884ad1f3f232



________________________________
From: Yade-dev [yade-dev-bounces+jerome.duriez=ucalgary.ca@xxxxxxxxxxxxxxxxxxx] on behalf of Bruno Chareyre [bruno.chareyre@xxxxxxxxxxxxxxx]
Sent: November-12-14 6:43 AM
To: yade-dev@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Yade-dev] Some cleaning in capillary law : data files validity

On 10/11/14 20:00, Jerome Duriez wrote:
Ok. I'm getting zero water volume for contacting spheres for an adimensionned capillary pressure Pc* =  1500 +/- 5 (the minimum adimensionned water volume seems to be ~ 2.6e-6)

Great. It means that 1500 was probably the max value when generating the data files.
There could be a warning in the code if Pc*>=1500, but it is only relevant for a specific set of data files...
The max should be defined automatically when reading the data.

B