Fluctuating sum local error

kalyangoparaju · August 7, 2012, 11:45

Guys,

I am having this problem where the sum local fluctuates between 10-30 for I have no idea why. I am running rhoPorousMRFSimpleFoam and everything seems to be right but sum local does this. Is there a reason why this happens and what exactly does this mean? If I increase the nNonOrthogonalCorrectors, it fluctuates between 0.1 and 2. After some iterations, when I check the solution, it gives pure rubbish results (negative pressure !!!) . I am quite sure all the initial and boundary conditions are right ( I have a fluent case for same numbers which gave me expected results)

Checkmesh doesnt report any errors. I tried fiddling with the relaxation settings and that doesn't help much. Also, I am running a first order upwind scheme.

Can someone tell me what all of this can mean?

Thanks,
Kalyan

kalyangoparaju · August 9, 2012, 14:05

The error has been resolved ..

Even though checkMesh hasn't given me any errors, looks like the mesh is not the best in the world. I had to use 10 nonOrthogonalCorrectors to get it to run and give me correct results.

Kalyan

August 7, 2012, 11:45	Fluctuating sum local error	#1
kalyangoparaju Member Kalyan Join Date: Oct 2011 Location: Columbus, Ohio Posts: 53 Blog Entries: 1 Rep Power: 14	Guys, I am having this problem where the sum local fluctuates between 10-30 for I have no idea why. I am running rhoPorousMRFSimpleFoam and everything seems to be right but sum local does this. Is there a reason why this happens and what exactly does this mean? If I increase the nNonOrthogonalCorrectors, it fluctuates between 0.1 and 2. After some iterations, when I check the solution, it gives pure rubbish results (negative pressure !!!) . I am quite sure all the initial and boundary conditions are right ( I have a fluent case for same numbers which gave me expected results) Checkmesh doesnt report any errors. I tried fiddling with the relaxation settings and that doesn't help much. Also, I am running a first order upwind scheme. Can someone tell me what all of this can mean? Thanks, Kalyan

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August 9, 2012, 14:05		#2
kalyangoparaju Member Kalyan Join Date: Oct 2011 Location: Columbus, Ohio Posts: 53 Blog Entries: 1 Rep Power: 14	The error has been resolved .. Even though checkMesh hasn't given me any errors, looks like the mesh is not the best in the world. I had to use 10 nonOrthogonalCorrectors to get it to run and give me correct results. Kalyan