2D simpleFoam simulation gets stuck - no error - problem with boundaries?

lovecraft22 · July 13, 2011, 06:14

Hi all;
trying to run a simple 2D circular cylinder.

I have already run that but I got a 3D resulting field so I slightly changed the boundary conditions and now the simulation gets stuck without any error at:

Code:

Time = 1

smoothSolver:  Solving for Ux, Initial residual = 0.407396, Final residual = 0.0155929, No Iterations 3
smoothSolver:  Solving for Uy, Initial residual = 0.485038, Final residual = 0.0173646, No Iterations 3

What you think could be the problem?
Maybe something related to my boundaries?

Thank you!

Lorenzo

lovecraft22 · July 13, 2011, 06:16

Update: I think it blows up and I get a floating point excepion…

Any help would be really appreciated!

Eren10 · July 13, 2011, 06:37

set-up normal files for BC , especially for U and p. I dont see why you are using complicates structure of the files, look to the tutorials

lovecraft22 · July 13, 2011, 08:32

Thank you Eren.

What do you mean with "Complicate file structure"?

lovecraft22 · July 13, 2011, 13:59

Ok, I simplified the boundary conditions for U and p (which I copied from the motorbike tutorial and that's why they were a little bit complicated).

Now, what should I set for the turbulence model (K-e) conditions?

lovecraft22 · July 13, 2011, 17:37

Eventually I managed to solve the case but I got a 3D solution instead of a 2D one, as you can see from the pressure plot on the surface:

What may the problem be?

Thank you!

Eren10 · July 14, 2011, 10:58

you want to simulate a 2D, so x and y . In the z direction only a one cell is required. if we asume x y forms the circular shape of the cylinder, than the domains parallel to the x- y plane should be empty.

lovecraft22 · July 14, 2011, 11:14

Tank you eren. If you look at my case directory you'll see that I already have only ove cell in z direction and both the planes perpendicular to the z-axis are already set as empty...

Eren10 · July 14, 2011, 11:28

I have no experience with the openfoam's way of generating the object, I am using an other program for mesh. so I cant help you. But make the distance in the z direction very small. but if that is oke, make a paint figure of the inlet outlet conditions etc.. in 2D, than we can check the BC.

lovecraft22 · July 14, 2011, 13:05

Inlet and outlet conditions (e.g. pressure) are perfectly 2D…

lovecraft22 · July 15, 2011, 14:51

I think I'll open another topic for this problem, since it's quite different from the one I started this topic for.

July 13, 2011, 06:14	2D simpleFoam simulation gets stuck - no error - problem with boundaries?	#1
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Hi all; trying to run a simple 2D circular cylinder. I have already run that but I got a 3D resulting field so I slightly changed the boundary conditions and now the simulation gets stuck without any error at: Code: Time = 1 smoothSolver: Solving for Ux, Initial residual = 0.407396, Final residual = 0.0155929, No Iterations 3 smoothSolver: Solving for Uy, Initial residual = 0.485038, Final residual = 0.0173646, No Iterations 3 What you think could be the problem? Maybe something related to my boundaries? Thank you! Lorenzo Last edited by lovecraft22; July 13, 2011 at 17:30.

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July 13, 2011, 06:16		#2
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Update: I think it blows up and I get a floating point excepion… Any help would be really appreciated!

July 13, 2011, 06:37		#3
Eren10 Member The True Join Date: Dec 2010 Posts: 80 Rep Power: 16	set-up normal files for BC , especially for U and p. I dont see why you are using complicates structure of the files, look to the tutorials

July 13, 2011, 08:32		#4
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Thank you Eren. What do you mean with "Complicate file structure"?

July 13, 2011, 13:59		#5
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Ok, I simplified the boundary conditions for U and p (which I copied from the motorbike tutorial and that's why they were a little bit complicated). Now, what should I set for the turbulence model (K-e) conditions?

July 14, 2011, 10:58		#7
Eren10 Member The True Join Date: Dec 2010 Posts: 80 Rep Power: 16	you want to simulate a 2D, so x and y . In the z direction only a one cell is required. if we asume x y forms the circular shape of the cylinder, than the domains parallel to the x- y plane should be empty.

July 14, 2011, 11:14		#8
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Tank you eren. If you look at my case directory you'll see that I already have only ove cell in z direction and both the planes perpendicular to the z-axis are already set as empty...

July 14, 2011, 11:28		#9
Eren10 Member The True Join Date: Dec 2010 Posts: 80 Rep Power: 16	I have no experience with the openfoam's way of generating the object, I am using an other program for mesh. so I cant help you. But make the distance in the z direction very small. but if that is oke, make a paint figure of the inlet outlet conditions etc.. in 2D, than we can check the BC.

July 14, 2011, 13:05		#10
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Inlet and outlet conditions (e.g. pressure) are perfectly 2D…

July 15, 2011, 14:51		#11
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	I think I'll open another topic for this problem, since it's quite different from the one I started this topic for.