Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Problem when restarting on a deformed mesh
Posted 2012年3月2日 GMT-5 04:03 Mesh, Studies & Solvers Version 4.2a 2 Replies
Please login with a confirmed email address before reporting spam
Beside my model problems I also get an error file type error message when trying to attach the pictures, hopefully everything should be clear without them.
I'm running into some problems when starting a new computation on a deformed mesh. The setup is as follows:
-2D-axisymmetric problem
-Three domains with fluid and moving mesh (highlighted in the attached picture)
-Three domains with solid mechanics and moving mesh (grey in attached picture)
Step 1: Solve a transient flow (spf)
Step 2: Use average pressure along with disp. BC on solid domain to calculate deformation. Create a deformed configuration for next step. (solid,ale)
Step 3: Run a new fluid simulation on the deformed configuration (spf)
I create the deformed mesh by right-clicking the solution data set from step 2 and select "Remesh deformed configuration". After checking that the created mesh looks OK I use it as mesh for Step 3. All initial values of the variables to be solved for are set to zero, i.e. nothing is used that was obtained on the old mesh.
Still the following error message displays when I start the solver for step 3:
"Undefined value found.
- Detail: Undefined value found in the equation residual vector.
.There are 3690 degrees of freedom giving NaN/Inf in the vector for the variable mod1.p
. at coordinates: (0,-0.05), (0.000901912,-0.05), (0.00180382,-0.05), (0.00270574,-0.05), (0.00811721,-0.05), ...
There are 3690 degrees of freedom giving NaN/Inf in the vector for the variable mod1.u2
. at coordinates: (0,-0.05), (0.000901912,-0.05), (0.00180382,-0.05), (0.00270574,-0.05), (0.00811721,-0.05), ...
There are 3690 degrees of freedom giving NaN/Inf in the vector for the variable mod1.w2
. at coordinates: (0,-0.05), (0.000901912,-0.05), (0.00180382,-0.05), (0.00270574,-0.05), (0.00811721,-0.05), .."
I also get a warning saying
"Warning: Inverted mesh element near coordinates (0, 0)."
Attached is also a quality plot of the remeshed mesh, which looks ok on the fluid domain.
Does anyone have any idea what the problem might be?
Thanks in advance,
Wiktor
I'm running into some problems when starting a new computation on a deformed mesh. The setup is as follows:
-2D-axisymmetric problem
-Three domains with fluid and moving mesh (highlighted in the attached picture)
-Three domains with solid mechanics and moving mesh (grey in attached picture)
Step 1: Solve a transient flow (spf)
Step 2: Use average pressure along with disp. BC on solid domain to calculate deformation. Create a deformed configuration for next step. (solid,ale)
Step 3: Run a new fluid simulation on the deformed configuration (spf)
I create the deformed mesh by right-clicking the solution data set from step 2 and select "Remesh deformed configuration". After checking that the created mesh looks OK I use it as mesh for Step 3. All initial values of the variables to be solved for are set to zero, i.e. nothing is used that was obtained on the old mesh.
Still the following error message displays when I start the solver for step 3:
"Undefined value found.
- Detail: Undefined value found in the equation residual vector.
.There are 3690 degrees of freedom giving NaN/Inf in the vector for the variable mod1.p
. at coordinates: (0,-0.05), (0.000901912,-0.05), (0.00180382,-0.05), (0.00270574,-0.05), (0.00811721,-0.05), ...
There are 3690 degrees of freedom giving NaN/Inf in the vector for the variable mod1.u2
. at coordinates: (0,-0.05), (0.000901912,-0.05), (0.00180382,-0.05), (0.00270574,-0.05), (0.00811721,-0.05), ...
There are 3690 degrees of freedom giving NaN/Inf in the vector for the variable mod1.w2
. at coordinates: (0,-0.05), (0.000901912,-0.05), (0.00180382,-0.05), (0.00270574,-0.05), (0.00811721,-0.05), .."
I also get a warning saying
"Warning: Inverted mesh element near coordinates (0, 0)."
Attached is also a quality plot of the remeshed mesh, which looks ok on the fluid domain.
Does anyone have any idea what the problem might be?
Thanks in advance,
Wiktor
2 Replies Last Post 2012年3月2日 GMT-5 08:04
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi
not obvious to propose something, from the error message it looks like that p and u2 are not passed settled fully between the solver steps.
One other thing, in v4.2a you should place the ALE physics node BEFORE the SOLID physics node in your node tree (this is not well documented), if it's not the case for you, try just to slide the ALE above the SOLID, and recheck ALL your BC and domain references from the ALE and the SOLID as such a change might override differently the BCs
--
Good luck
Ivar
not obvious to propose something, from the error message it looks like that p and u2 are not passed settled fully between the solver steps.
One other thing, in v4.2a you should place the ALE physics node BEFORE the SOLID physics node in your node tree (this is not well documented), if it's not the case for you, try just to slide the ALE above the SOLID, and recheck ALL your BC and domain references from the ALE and the SOLID as such a change might override differently the BCs
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Thanks for your reply!
I've seen it previously in the forums how the ale node should be before solid, although the tutorial "Remeshing a Deformed Geometry—A Quick Example" suggests the other way round. Anyway now I've tried both ways, with checking the BC's in between, and the problem persists.
How do you mean that the variables aren't passed fully between the study steps? I restart with zero initial solution for all flow variables so I didn't think (in fact I don't want) what has happend earlier should have any effect.
Also this inverted mesh element warning is strange since the mesh shouldn't deform during the spf analysis and the mesh looks fine before starting.
In the tutorials that I've seen they have always restarted the solution on the deformed mesh but I want to start a new analysis, something that I think should be possible. Have anyone had success in doing so the way I described?
Regards,
Wiktor
I've seen it previously in the forums how the ale node should be before solid, although the tutorial "Remeshing a Deformed Geometry—A Quick Example" suggests the other way round. Anyway now I've tried both ways, with checking the BC's in between, and the problem persists.
How do you mean that the variables aren't passed fully between the study steps? I restart with zero initial solution for all flow variables so I didn't think (in fact I don't want) what has happend earlier should have any effect.
Also this inverted mesh element warning is strange since the mesh shouldn't deform during the spf analysis and the mesh looks fine before starting.
In the tutorials that I've seen they have always restarted the solution on the deformed mesh but I want to start a new analysis, something that I think should be possible. Have anyone had success in doing so the way I described?
Regards,
Wiktor