roatating block with ggi - continuity error?
 

Dear all

I am not sure whether it is appropriate to ask this question here. I am trying to simulate a rotating propeller problem. After I did a bit search on thw Internet, I found that it is possible to do it with a rotating ggi. However, ggi requires OpenFOAM 1.6 extended release.

Q1: I am using OpenFOAM 1.6 and I am not sure whether it is hard to upgrade to the extend version?

Q2: I just wonder whether it is possible to do the same job just with OpenFOAM 1.6 with some other setup?

Q3: I looked at some Turbomachinery tutorials and I found they are not very straigh forward. Is there any other tutorials on the rotating mesh simulations?

Thank you very much.

Hello,

you can only use GGI with Openfoam 1.5-dev and Openfoam 1.6-extent.
OpenCFD's Openfoam does not support GGI only the community distribution supports GGI

If you use a Debian/Ubuntu based Distribution you can use the binany packets from
https://launchpad.net/~cae-team/+arc...s_filter=lucid
read what you need to do to add to your sources.list entries
installing a binary should be pretty simple

if you do not use a debian based distribution ALIEN might help you
=> http://kitenet.net/~joey/code/alien/ or http://packages.debian.org/en/lenny/alien

Well, if you use ubuntu or debian just apt-get
http://openfoamwiki.net/index.php/In...ucid_10.04_LTS

=> you can have more than one or two installations of openfoam just have approprate aliases in your .bashrc and start the version by calling the alias you want to work with
alias startOF15dev='source /usr/lib/OpenFOAM-1.5-dev/etc/bashrc'
alias startOF16ext='source /usr/lib/OpenFOAM-1.6-ext/etc/bashrc'
alias startOF17='source ....bashrc'

startOF16ext or startOF15dev or startOF17

Hi Elvis

Thanks for the quick reply. I will give it a try with OF16ext. I just wonder whether there is any relevant tutorial case files I can start with? Basically, I am trying to learn how to set up a ggi case file.

Hi,
take a look at mixerGGI (icoDyMFoam) it should be in the tutorials
http://openfoam-extend.svn.sourcefor...Foam/mixerGgi/

do not know where it is in version 1.6-extend but structure of the tutorials should not have changed to dramaticly

I hope I point in the right direction, if this does not help you enough you might
join the email list of the SIG Turbomachinery and contact experts there
read http://openfoamwiki.net/index.php/Sig_Turbomachinery

greets

elvis

Hi elvis

I compiled 1.5-dev on my Ubuntu 9.10 (a bit harder than I expected). I realised there are mixer2D and mixerGgi under icoDyMFoam. It is clear that mixerGgi uses ggi interface. What about mixer2D? I looked at its DynamicMeshDict and the boundary condition. It seems that mixer2D uses "movingWallVelocity" for both insideSlider and outsideSlider. Does this mean the velocity won't pass these two patches so that there will be not interaction between the rotator and the stator?

I guess my question is what is the difference between the two cases?

Thanks

The continuity error was fixed by reducing the gap between insideSlider and outsideSlider.

The continuity error was fixed by reducing the gap between insideSlider and outsideSlider.

If I want to extend the 2d mixer ggi case to 3d case (extrude) in the z-direction. How should I set the boundary condition for the top and bottom patches - "frontAndBackPlanes" in 2d case (e.g. wall or movingWallVelocity)? or should I set the part in the "insideSlider" as movingWallVelocity and the part in the "outsideSlider" as wall?

Thanks a lot

Dear Jie,

I am not a GGI user, maybe you can benefit from http://www.tfd.chalmers.se/~hani/kurser/OS_CFD_2009/
=>Advanced OpenFOAM usage, taught by Olivier Petit
Mesh generation (snappyHexMesh etc.), MRFSimpleFoam, GGI...
Mesh generation
Case descriptions http://www.tfd.chalmers.se/~hani/kur...dy_2009_OP.pdf
Files http://www.tfd.chalmers.se/~hani/kur...ivierFiles.tgz

otherwise if you do not make progress I would contact a GGI "Poweruser" => Martin Beaudoin or Hakan Nilsson from SIG Turbomachinery
http://openfoamwiki.net/index.php/Sig_Turbomachinery
http://www.extend-project.de/compone...ry-group-forum

greets

elvis

Thanks elvis. I will give them a try first.

Hi elvis, I looked at the links you provided. I found most of them have an inner mesh rotates around an outer mesh, which is like the mixer case.

I think the case I am doing might be similar to the tutorial at http://openfoamwiki.net/index.php/Si...nical_diffuser. However it did not use the GGI but it is suggested = to use GGi for the future study at section 1.10.1.

For a rotating propeller, the mesh topology looks something like this:

inlet -> __________ ->
inlet -> | A | B | C | -> outlet
inlet -> -------------- ->

The flow field is like a circular pipe with three sections (A, B and C). The propeller is in section B and I am trying to use the GGI interface between A and B, B and C (B is the rotating part). Should I leave small gaps between A and B, B and C and apply the same GGI setup as the mixer case?

Hope the explanation is clear to you.

Thanks a lot.