yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxxxxxx>]

Hi Robert,
It sounds good, except that I would increment kNorm directly instead of 
incrementing a counter.
Logic:
- two adjacent cracks cumulate their conductivity: Ktot = K1+K2
- if you accumulate aperture you get (a1+a2)^3 instead of (a1^3  + 
a2^3), it will increase to much it seems.

I know there can still be some form of non linearity depending on the 
count but the cube of the sum is to much IMO.

Bruno

On 09/02/2018 03:39 PM, Robert Caulk wrote:
> Hello,
>
> I am working on a check test for DFNFlow in which I use pressure and 
> aperture as pass criteria. However, I want this check script to be a 
> repeatable baseline for DFNFlow, so I'd like to remove/replace the 
> existing uncertainty associated with tricking permeability. If this 
> change may affect you, please review the following and reply with your 
> comments/suggestions.
>
> *_Existing problem:_*
> Currently, DFNFlow tricks facet permeability by using the most 
> recently visited edge, which means the tricked facet permeability has 
> no physical basis, in fact, it depends on the order of the C++ for loop.
>
> _*Discussed solution:*_
> Luc, Timos, Bruno, and I discussed this a bit in Aix-en-Provence and 
> agreed(?) that we should increment the total aperture of a facet for 
> every broken edge associated with that facet. In other words, if one 
> facet has 2 broken edges, the aperture used to trick facet 
> permeability is the summation of both apertures (instead of the most 
> recently visited edge during tickPerm loop). Thus, the aperture 
> incrementation method has some physical basis and no longer depends on 
> the order of C++ for loop.
>
> If we want/need to keep the uncertain trickPerm method around, let me 
> know and I will add a flag for you.
>
> *_Proposed changes to DFNFlow.cpp [1]:_*
>
> DFNFlow.cpp around line 245:
>
> // increment the facet's aperture member:
> if (cell1->info().count()[currentFacet.second] < 3){
> cell1->info().count()[currentFacet.second] += 1;
> cell1->info().aperture()[currentFacet.second] += aperture;
> }
>
> // use the incremented facet aperture member to update facet permeability:
> cell1->info().kNorm()[currentFacet.second] = 
> cell2->info().kNorm()[Tri.mirror_index(cell1,currentFacet.second)] = 
> apertureFactor*pow(cell1->info().aperture()[currentFacet.second],3)/(12*viscosity);
>
> *_Status:_*
> I used this method for creating the DFNFlow check script - the code is 
> stable and produces repeatable pass criteria.
>
> Cheers,
>
> Robert
>
> [1]https://github.com/yade/trunk/blob/master/pkg/pfv/DFNFlow.cpp
>
>
>
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