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-   -   How to mesh a pipe network using helyxOS (http://www.cfd-online.com/Forums/openfoam-meshing/128906-how-mesh-pipe-network-using-helyxos.html)

EFoster2 January 23, 2014 16:01

How to mesh a pipe network using helyxOS
 
3 Attachment(s)
Hey all,

I am trying to make a pipe network for my dissertation this year. So far I have just been creating simple singular rectangular pipes using helyxOS. I am now trying to expand that so I have a bifurcating network as shown in the attachments and try and achieve the level of refinement in the corners as shown in the mesh refinement photo.

I have had two ideas so far and that would be to create a stl of the geometry and snap to it or create lots of surface/volume regions. I reckon the former might be a bit more computationally intensive than the later but since I have very little experience with linux and openFoam in general that's where my ideas run out altogether.

I was wondering if anyone on this forum would be able to give their opinions on what might be the best out of the two options and briefly describe the steps they would take to accomplish this geometry? Bare in mind computational resources are pretty limited as I am in the middle of building a new pc and only have my laptop.

I appreciate any help I get.

Euan!

chegdan January 23, 2014 16:26

Greetings!

I noticed this is your first post, so welcome to the forum! My suggestion is to start with the easier option first. Create your geometry as an STL and then adjust the featureAngle as needed to capture more of the features. Most of the time, to capture more you need to lower your base mesh spacing. I would look at a few presentations to get you going

Some changes have happened in snappyHexMesh and HELYX-OS that are a little different than these talks...but you can always ask a question if its not clear.

EFoster2 February 3, 2014 16:24

Hey Dan,

Thanks a lot for the help! I tried doing that and it worked fine. My supervisor though wanted something a bit more streamlined and better thought out.

I extended the mesh by creating the full 207 vertices required in blockMesh. I found this post pretty useful on how to create the mesh using blockMesh - http://www.cfd-online.com/Forums/ope...ockmesh-2.html.

I occasionally transferred my mesh into helyxOS to check I had selected all the right patches and were labeling them correctly. Likewise, I found this helpful - http://www.cfd-online.com/Forums/ope...-helyx-os.html.

Again thanks for the reply. I also checked out your twitter. You seem like THE man when it comes to CFD in general.

Euan

chegdan February 3, 2014 17:05

Glad it helped you so far and thanks for the compliment! If you find blockMesh does it for you then by all means go with what works. You may also be able to do it directly with snappyHexMesh using something like

Code:

twoBoxes
 {
      type searchableSurfaceCollection;
      mergeSubRegions true;
 
      boxA
      {
          surface box;
            scale (1.0 1.0 2.1);
            transform
            {
                type cartesian;
                origin (2 2 0);
                e1 (1 0 0);
                e3 (0 0 1);
            }
      }
      boxB
      {
            surface box;
            scale (1.0 1.0 2.1);
            transform
            {
                type cartesian;
                origin (3.5 3 0);
                e1 (1 0 0);
                e3 (0 0 1);
            }
      }
 }

but use cylinders instead.

Dan


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