Dynamic Mesh Simulation

de098 · August 18, 2020, 12:17

Hi All!

I'm trying to generate a simulation of a rotating mesh that has multiple frames so that it can be played back in Paraview like the Cantilever example in the Structural Mechanics section, but I can't seem to find much information about how to do it.

I tried adding the following sections to the config but I think I'm missing something since the mesh doesn't rotate in Paraview when played back:

HTML Code:

GRID_MOVEMENT= ROTATING_FRAME
 MACH_MOTION= 0.8
MOTION_ORIGIN= 0.25 0.0 0.0
ROTATION_RATE = 9.0 9.0 9.0
TRANSLATION_RATE = 4.0 3.0 0.0

Is there an example config file that can be used as a starting point for this sort of thing?

Thanks!

pcg · August 18, 2020, 12:29

Hi,
Rotating frame simulations do not move the grid, they just assume the region is rotating without actually moving it, hence the "frozen rotor" designation in the turbomachinery world.
In any case, what you want is rigid motion, of the rotating flavor, see TestCases/sliding_interface/rotating_cylinders/
Cheers.

de098 · August 20, 2020, 19:41

Thanks for the quick reply, sorry it took me some time to get back to you.
I ran the simulation on the test case, and it's hitting:

HTML Code:

FGMRES orthogonalization failed, linear solver diverged.

After iteration 878.

This is on the latest MPI download for macOS, is this a known issue/expected?

Thanks!

Update: When running non-MPI version it ends with:

HTML Code:

SU2 has diverged. (Residual > 10^20 detected)

After 765 iterations

pcg · August 21, 2020, 06:00

Regression tests are not validation examples.
We use them to detect changes to particular features.
Some are a bit contrived so yeah they may diverge after some iterations...
But I only pointed you to that case so you can get a reference for the required options.

August 18, 2020, 12:17	Dynamic Mesh Simulation	#1
de098 New Member Join Date: Aug 2020 Posts: 2 Rep Power: 0	Hi All! I'm trying to generate a simulation of a rotating mesh that has multiple frames so that it can be played back in Paraview like the Cantilever example in the Structural Mechanics section, but I can't seem to find much information about how to do it. I tried adding the following sections to the config but I think I'm missing something since the mesh doesn't rotate in Paraview when played back: HTML Code: GRID_MOVEMENT= ROTATING_FRAME MACH_MOTION= 0.8 MOTION_ORIGIN= 0.25 0.0 0.0 ROTATION_RATE = 9.0 9.0 9.0 TRANSLATION_RATE = 4.0 3.0 0.0 Is there an example config file that can be used as a starting point for this sort of thing? Thanks!

August 20, 2020, 19:41		#3
de098 New Member Join Date: Aug 2020 Posts: 2 Rep Power: 0	Thanks for the quick reply, sorry it took me some time to get back to you. I ran the simulation on the test case, and it's hitting: HTML Code: FGMRES orthogonalization failed, linear solver diverged. After iteration 878. This is on the latest MPI download for macOS, is this a known issue/expected? Thanks! Update: When running non-MPI version it ends with: HTML Code: SU2 has diverged. (Residual > 10^20 detected) After 765 iterations Last edited by de098; August 20, 2020 at 20:55. Reason: Providing update.

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August 18, 2020, 12:29		#2
pcg Senior Member Pedro Gomes Join Date: Dec 2017 Posts: 465 Rep Power: 13	Hi, Rotating frame simulations do not move the grid, they just assume the region is rotating without actually moving it, hence the "frozen rotor" designation in the turbomachinery world. In any case, what you want is rigid motion, of the rotating flavor, see TestCases/sliding_interface/rotating_cylinders/ Cheers.

August 21, 2020, 06:00		#4
pcg Senior Member Pedro Gomes Join Date: Dec 2017 Posts: 465 Rep Power: 13	Regression tests are not validation examples. We use them to detect changes to particular features. Some are a bit contrived so yeah they may diverge after some iterations... But I only pointed you to that case so you can get a reference for the required options.