Odd behaviour in circuitBoardCooling

sturgeon · April 18, 2018, 15:34

If I run the circuitBoardCooling tutorial case with buoyantSimpleFoam, entirely unmodified, except for removing the thermal baffles, the converged result looks like this:

So there's an odd vertical velocity at the top and bottom of the inlet. There's also slight checkerboarding, as you can see from this plot of Uy versus y axis from just inside the inlet:

Does anyone know why this is? I assume it's to do with the inlet, which is a consistent fixed velocity, encountering the noslip walls, where the converged solution is not going to be a consistent internal field of that fixed velocity. But I can't figure out how to fix it after searching online a lot. Any insight is greatly appreciated

Thanks

piu58 · April 19, 2018, 00:45

It would be helpful if you'd posted your case or at least the file(s) you changed. You made some kind of error, of course. But without knowing your case, nobody can guess at which detail.

sturgeon · April 19, 2018, 06:22

Sorry, I thought I was clear. This is literally an exact copy of the circuitBoardCooling tutorial from buoyantSimpleFoam, except I never executed the command to add the thermal baffles. I didn't change anything else. If you take the circuitBoardCooling case, rename the 0.orig to 0, execute blockMesh and buoyantSimpleFoam, you will have this case.

sturgeon · April 26, 2018, 08:22

Sorry to bump but does anyone have any information on this? It's plaguing some other cases of mine. Cheers

April 18, 2018, 15:34	Odd behaviour in circuitBoardCooling	#1
sturgeon Member Join Date: Jun 2017 Posts: 58 Rep Power: 8	If I run the circuitBoardCooling tutorial case with buoyantSimpleFoam, entirely unmodified, except for removing the thermal baffles, the converged result looks like this: So there's an odd vertical velocity at the top and bottom of the inlet. There's also slight checkerboarding, as you can see from this plot of Uy versus y axis from just inside the inlet: Does anyone know why this is? I assume it's to do with the inlet, which is a consistent fixed velocity, encountering the noslip walls, where the converged solution is not going to be a consistent internal field of that fixed velocity. But I can't figure out how to fix it after searching online a lot. Any insight is greatly appreciated Thanks

April 19, 2018, 00:45		#2
piu58 Senior Member Uwe Pilz Join Date: Feb 2017 Location: Leipzig, Germany Posts: 744 Rep Power: 15	It would be helpful if you'd posted your case or at least the file(s) you changed. You made some kind of error, of course. But without knowing your case, nobody can guess at which detail. __________________ Uwe Pilz -- Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950)

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April 19, 2018, 06:22		#3
sturgeon Member Join Date: Jun 2017 Posts: 58 Rep Power: 8	Sorry, I thought I was clear. This is literally an exact copy of the circuitBoardCooling tutorial from buoyantSimpleFoam, except I never executed the command to add the thermal baffles. I didn't change anything else. If you take the circuitBoardCooling case, rename the 0.orig to 0, execute blockMesh and buoyantSimpleFoam, you will have this case.

April 26, 2018, 08:22		#4
sturgeon Member Join Date: Jun 2017 Posts: 58 Rep Power: 8	Sorry to bump but does anyone have any information on this? It's plaguing some other cases of mine. Cheers