interDyMFoam with GGI in 3d

stawrogin · January 8, 2010, 06:04

Dear Foamers,
First of all a HAPPY NEW YEAR to all Foamers.
I took a quite challenging task for beginning of this year: I started to try some simulation with interDyMFoam and GGI. My model is quite similar to the mixer case already discussed here (http://www.cfd-online.com/Forums/openfoam-solving/68375-interdymfoam-ggi.html) but I would like to extend it to 3d. This case is derived from the mixerggi for icoDyMFoam.
I think, I performed only slight changes: I increased the mixer thickness using 10 cells, set a symmetry plane instead of empty and increased the overall resolution of the mesh. Here, the solution diverges after few iterations. The solution behavior looks quite strange, e.g. gamma reaches values above “1” and below “0”. I tried a lot to fix this, e.g. using smaller time steps, increasing the gamma-iterations… So I wonder if there is something wrong in my settings, or if interDyMFoam might need some modifications for GGI or if mixerGgiFvMesh might need some changes for interDyMFoam. So my question is: Did anybody already solve more complex cases with GGI and interDyMFoam for rotating geometries? What is the general experience regarding stability and solution time?
Thanks
Stawrogin

myheroisalex · January 27, 2010, 14:48

HeyHey,

20 days later, but maybe you still need a hint:
I got the same problem with the gamma-values using InterDyMFoam (but not GGI). It seems as if the Mules-solver got a problem with moving-mesh. In my case I got increasing gamma-values for nGammaSubCycles > 1 and gamma values getting negative für nGammaSubCycles = 0 or 1.
Maybe you should have a look at this thread here:
http://www.cfd-online.com/Forums/ope...sh-motion.html

Good luck

jiejie · January 5, 2011, 03:17

Hi stawrogin

I tried to extend the 2d mixer ggi case to 3d as well, but I end up with Segmentation fault. I think it is probably due to the incorrect assignment of the boundary condition for the top and bottom patches.

I just wonder how you set up the boundary condition for the top and bottom patches (these are used to be the "frontAndBackPlanes" in 2d case).

or do you set the parts of the top and bottom ptches in the "insideSlider" and the part in the "outsideSlider" separately? If so, How?

Thank you very much.

January 8, 2010, 06:04	interDyMFoam with GGI in 3d	#1
stawrogin Member Join Date: Nov 2009 Posts: 36 Rep Power: 17	Dear Foamers, First of all a HAPPY NEW YEAR to all Foamers. I took a quite challenging task for beginning of this year: I started to try some simulation with interDyMFoam and GGI. My model is quite similar to the mixer case already discussed here (http://www.cfd-online.com/Forums/openfoam-solving/68375-interdymfoam-ggi.html) but I would like to extend it to 3d. This case is derived from the mixerggi for icoDyMFoam. I think, I performed only slight changes: I increased the mixer thickness using 10 cells, set a symmetry plane instead of empty and increased the overall resolution of the mesh. Here, the solution diverges after few iterations. The solution behavior looks quite strange, e.g. gamma reaches values above “1” and below “0”. I tried a lot to fix this, e.g. using smaller time steps, increasing the gamma-iterations… So I wonder if there is something wrong in my settings, or if interDyMFoam might need some modifications for GGI or if mixerGgiFvMesh might need some changes for interDyMFoam. So my question is: Did anybody already solve more complex cases with GGI and interDyMFoam for rotating geometries? What is the general experience regarding stability and solution time? Thanks Stawrogin

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January 27, 2010, 14:48		#2
myheroisalex New Member Michael G. Join Date: Sep 2009 Location: Germany, Nds. Posts: 13 Rep Power: 17	HeyHey, 20 days later, but maybe you still need a hint: I got the same problem with the gamma-values using InterDyMFoam (but not GGI). It seems as if the Mules-solver got a problem with moving-mesh. In my case I got increasing gamma-values for nGammaSubCycles > 1 and gamma values getting negative für nGammaSubCycles = 0 or 1. Maybe you should have a look at this thread here: http://www.cfd-online.com/Forums/ope...sh-motion.html Good luck

January 5, 2011, 03:17		#3
jiejie Senior Member Jie Join Date: Jan 2010 Location: Australia Posts: 134 Rep Power: 16	Hi stawrogin I tried to extend the 2d mixer ggi case to 3d as well, but I end up with Segmentation fault. I think it is probably due to the incorrect assignment of the boundary condition for the top and bottom patches. I just wonder how you set up the boundary condition for the top and bottom patches (these are used to be the "frontAndBackPlanes" in 2d case). or do you set the parts of the top and bottom ptches in the "insideSlider" and the part in the "outsideSlider" separately? If so, How? Thank you very much.