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Unknown degree of freedom when trying to solve an FSI model
Posted 22.05.2010, 11:37 GMT-4 3 Replies
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Hello,
I am trying to model a robot inside a water pipe and am interested in finding out the forces exerted on the robot due to the flow of water. I have modelled a pipe and a simple robot representation and have imported and positioned those in COMSOL. I also modelled some caps which I have placed on either end of the pipe. Under the FSI node, I added inlet and outlet boundary conditions (using the caps) and then added a fixed constraint to everything (since nothing will move). After meshing and trying to solve the simulation I get the following error:
Unknown degree of freedom. - Degree of freedom: x at (0.5, 0, 0)
How can I repair this?
Thanks
--Amr
P.S. Model file attached
I am trying to model a robot inside a water pipe and am interested in finding out the forces exerted on the robot due to the flow of water. I have modelled a pipe and a simple robot representation and have imported and positioned those in COMSOL. I also modelled some caps which I have placed on either end of the pipe. Under the FSI node, I added inlet and outlet boundary conditions (using the caps) and then added a fixed constraint to everything (since nothing will move). After meshing and trying to solve the simulation I get the following error:
Unknown degree of freedom. - Degree of freedom: x at (0.5, 0, 0)
How can I repair this?
Thanks
--Amr
P.S. Model file attached
Attachments:
3 Replies Last Post 24.06.2010, 09:39 GMT-4
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Posted:
1 decade ago
So far I did not have luck with Comsol 4 and FSI. If you can, use v3.5a until the new fix is out.
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Posted:
1 decade ago
I am currently getting the same error message when trying out the "Obstacle in Fluid" tutorial in COMSOL 4.0. I'll post if I can get it figured out, but looks like I'm going back to version 3.5a.
Thanks,
John
Model file is attached.
Error Message:
Unknown degree of freedom.
- Degree of freedom: x at (0.5,0,0)
Thanks,
John
Model file is attached.
Error Message:
Unknown degree of freedom.
- Degree of freedom: x at (0.5,0,0)
Attachments:
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
This still seems to be an issue with 3D fsi models in COMSOL 4.0.
However, changing the solver from iterative to direct seems to work.
However, changing the solver from iterative to direct seems to work.