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2D adaptive Mesh Refinement

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Old   June 5, 2013, 13:44
Default 2D adaptive Mesh Refinement
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Hello Foamers,

i am new here.

i am not sure if it is right posting my problem in this forum... i hope it is ok.
I did create an adaptive mesh using dynamicRefineFvMesh. I adapted the hexRef8 class for splitting cells in 2D. Now i started my solver and the cell refinement runs good (the mesh check is OK) and now the big BUT it comes ...
Always if the mesh changes the calculations will be solved in 3D, i.e. the vector of velocity is directed in the 3.dimension.
And now comes sth weird. If i stop the calculation and then i re-start it from the last timestep then the calculation is correctly calculated in 2D. What is the problem, i have absolutely no idea.

many thanks
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Old   June 7, 2013, 03:11
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dear buddy, maybe you want to share your code and one test case here, maybe we can help you to solve the problem
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Old   July 17, 2013, 14:45
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Haomin Yuan
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Hey,

As far as I know, the cut engine hexRef8 is only capable to cut cell into 8 subcells, which means it is 3 dimensions. I have seen a paper talking about cut cells in to 2 subcells, I think you look it up here:
http://publications.lib.chalmers.se/...173/174173.pdf

Another question is, what solver are u using? I am now trying to implement AMR into steady solver.But I met some problems.
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Old   July 28, 2013, 10:04
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Johannes P
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I'm also working on a 2D adaptive mesh refinement with a dynamicFvMesh. Does anybody have an idea whether it's good to start modifying the hexRef8 class, keeping its low-level style (which is really complicated) or if one could adapt hexRef8, keep using all its nice features and just plug in simpler mesh modification operations?

I successfully managed to do exactly the refinement I want using multiDirRefinement which gives me the type of meshes I want BUT It still lacks all the other capabilities which are needed for a dynamic mesh (like: field mapping, keeping track of the refinement history, allowing unrefinement etc.)

What I'd like to do is: take hexRef8 and rewrite it partially, using the code from multiDirRefinement, thus turning it into a hexRef4 or hexRef2.

Does anybody have a good idea how to start?
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Old   May 31, 2016, 10:00
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Have you seen this thesis? (http://digitalcommons.mtu.edu/cgi/vi...8&context=etds)
Especially Apendix B.

It seems like the 2D adaptive mesh refinement we are looking for.
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Old   July 19, 2016, 14:39
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Hi,

does anyone of you managed to implement the 2D engine for dynamic local mesh refinement?

I'm trying to do it according to mentioned paper: [Ahmad Baniabedalruhman] http://digitalcommons.mtu.edu/etds/1005/[/URL]

I'm currently struggling with the code from appendix B related to splitting of internal faces. Does anyone know how the variable anchorPointJ should be initialized? It is appearing on the page 173 when author is proposing the algorithm for splitting internal faces.

Regards,
Jakub.
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Old   July 20, 2016, 04:46
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Hi Jakub,

I am also currently trying to get the adaptive mesh refinement to run in 2D following the Baniabedalruhman thesis.

It seems to me that the modifications are neither complete nor all correct.
With some modifications, I was able to compile the new library but my code crashes during the first refinement step.

For the anchorPointJ I have added:
label anchorPointJ = anchors.otherVertex(anchorPointI);


Send me a PM if you are interested in a discussion

Hannes
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Old   July 21, 2016, 11:40
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Hi Hannes89,

I am interested in adaptive mesh refinement.
I found and fixed some problems, but I still don't understand how to declare:
-anchorPointJ
-isDivisibleFace
-isDivisibleEdge.

Did you solve the problems?
Could you help me?

Regards,
Carmelina
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Old   July 21, 2016, 14:47
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Jakub Pola
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Catelyn,

together with Hannes89, we are trying to implement this solution. You can join us if you want. The more the better

On monday I will try to give you some hints regarding those variables.

Regards,
Jakub.
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Old   July 25, 2016, 06:02
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Hi Catelyn,

the isDivisible variables should be boolean lists, holding a value for every face and edge, that can be declared like this:

boolList isDivisibleFace(mesh_.nFaces(),false);
boolList isDivisibleEdge(mesh_.nEdges(),false);

Regarding the anchorPointJ. I am not so sure about the algorithm implemented in the PhD thesis and can not give you a definitive answer.
I am currently trying to rewrite this bit of the code.

Hannes
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Old   July 25, 2016, 06:10
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Jakub Pola
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Hi,

here are my thoughts regarding variables you asked.
  • isDivisibleFace - this is a bool list pointing if the face can be splitted. Faces on the empty boundary should be divided to four new faces, the others into two. I would use boolList at first glance, later it could be changed to PackedBoolList. The size is nFaces(). So the full declaration will be:

    Code:
    boolList isDivisibleFace(mesh_.nFaces(), 0)
  • isDivisibleEdge - here similarly it is a list which index corresponds to edge index in the mesh. If the isDivisibleEdge[index] = true then edge number equal ti index can be splitted for creating new faces in the mesh.

    Code:
    boolList isDivisibleEdge(mesh_.nEdges(), 0)

When it comes to anchorPointJ, we don't know yet what it should be.

Kuba.
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Old   July 26, 2016, 05:30
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Thank you all,
I realized they were boolean variables but I have a too approximate knowledge in programming.
I wrote to Dr. Baniabedalruhman, I'll keep you posted if I receive any answers.

Catelyn
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Old   November 13, 2016, 00:44
Talking 2d amr
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Quote:
Originally Posted by catelyn View Post
Thank you all,
I realized they were boolean variables but I have a too approximate knowledge in programming.
I wrote to Dr. Baniabedalruhman, I'll keep you posted if I receive any answers.

Catelyn
Have you succeed? , recently I also refer to Dr .Baniabedalruhman's thesis for 2D AMR, but still a lot of problems? How to define the variable of anchorPointJ ? Coud you give me some hints how to make the 2D AMR run successfully,please? Thank you.
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Old   November 14, 2016, 11:26
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Quote:
Originally Posted by supersoldier View Post
Have you succeed? , recently I also refer to Dr .Baniabedalruhman's thesis for 2D AMR, but still a lot of problems? How to define the variable of anchorPointJ ? Coud you give me some hints how to make the 2D AMR run successfully,please? Thank you.
No, I didn't, and he didn't reply.

Catelyn
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Old   November 20, 2016, 10:47
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I have study the codes at Appendix B in the thesis of http://digitalcommons.mtu.edu/cgi/vi...8&context=etds. I changed the codes as the thesis suggest, but when I run my 2d heat transfer case, there's error. And I output the debug informaion, I found basically those values are right.

I find the error was occur in the function createInternalFaces ( original in file hexRef8.C for 3D ,but I change this file hexRef4.C for 2D) .

The "if (edgeMidPointI==-1)" judgement ,which I think is the key problem, because for 2D problem ,the value of edgeMidPointI of empaty boundary 's edge are not -1, but the value of edgeMidPointI of internal edges are -1, so when loop the interal edge this judgement is right, it will output the wrong message,and stop the programm.

So, I look into the function of storeMidPointInfo, I want to do some change, but I do not unstand its theory. I will continue to handle this problem. Is there anyone can give me some help how to sovle this problem?

If I successed to run the 2D AMR , I will show the codes!





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Old   November 30, 2016, 09:52
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Hi,

I recently started to work on this problem too. I tried to implement the (in)famous code described in Dr. Baniabedalruhman's thesis in Openfoam 3.2 extend, whose dynamicMesh libraries are very close to the "standard" version.

As already reported, the description of the code in the thesis is quite incomplete. After some modification, I reached the same point of XuDongNa: when runiing the solver, the refinement process stops when the first cell is split as the createInternalFaces function sends an error because the edgeMidPointl is not set.

Unfortunately, I don't have much time to work on this.
Where you able to solve the problem?
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