Modelling granular materials with capillary forces

Asked by NDONG MBELE on 2020-06-18

Hi all,

I am a new YADE user. The purpose of my internship is to follow the slip between two layers of spheres depending on the angle of inclination of the support, the first layer being fixed, and the second subjected to capillary and gravitational forces.

In the first step, I created a base layer by filling a box, then sedimentation by gravity until the spheres (fixed) stopped. I saved simulation 1 ( ("1st-step.yade"))

In the second step, I called the simulation 1st-step.yade (O.load ("1st-step.yade")), then I created a repository of a layer of spheres of different size and less dense (which will be mobile). I saved simulation 2 ( ("2st-step.yade"))

Now, I want to introduce the capillary forces, but it turns out that I face several difficulties:

 1) The use of Law2_ScGeom_CapillaryPhys_Capillarity:

How to generate a set of capillary files M (r = i) (for example, for another wetting angle other than zero) ?.

2) How can I introduce capillary forces to avoid segmentation errors?


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Jérôme Duriez
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Jérôme Duriez (jduriez) said :


1. Generation of capillary files is at [1], you will have to run the MATLAB function writesCapFile.m (Python usage is not very far from current status but not here yet). Please see the readme.txt therein and let us know if something is unclear

2. Once you have the capillary files in the folder where you run YADE, and a correct definition of Law2_ScGeom_CapillaryPhys_Capillarity engine, you should get no segmentation fault. You can start practicing with in [1]


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NDONG MBELE (ndong96) said :


thanks for the answer, it helped me a lot

1) So if I understood correctly, the generation of the 10 text files M (r = i) is only done on mathlab? if so, i think you have answered my question.

2) After having downloaded the 10 capillary files (for a zero wetting angle) given by wiki, the execution of the code works without problem.

3) I would now like to know if there is a way to tilt the support plane in order to be able to follow the destabilization of the particles (which are subjected to the force of gravity and capillary forces) by virtue of the angle of inclination of the support plan.


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Best Jérôme Duriez (jduriez) said :

1) Yes. If you prefer Python, it should not be so difficult to write a Python equivalent to writesCapFile.m, which is the last piece missing for a complete Python usage.

3) Please open a new question since it is no longer related to capillary forces. Before opening a new question, documentation about controlling bodies' movement (a rotation here, if I understand correctly) should help: starting from

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NDONG MBELE (ndong96) said :

Thanks Jérôme Duriez, that solved my question.