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 The information provided may be out of date.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.
Moving box in the fluid problem
Posted Feb 22, 2012, 8:44 a.m. EST Version 4.2 2 Replies
Please login with a confirmed email address before reporting spam
Hi,
I am working with 2D natural convection problem that has a moving box inside.
I added conjugate heat transfer and moving mesh.
As I attached a file, I have three problems.
1. The moving material's meshes are broken sometimes during solving.
Is it possilbe to improve by automatic remeshing?
2. Can i check moving material's temperature?
3. In 2D surface plot, I found that material is not moving. I think this may be because Conjugate heat transfer and Moving mesh were not coupled. How can I check whether these are coupled?
Thanks.
I am working with 2D natural convection problem that has a moving box inside.
I added conjugate heat transfer and moving mesh.
As I attached a file, I have three problems.
1. The moving material's meshes are broken sometimes during solving.
Is it possilbe to improve by automatic remeshing?
2. Can i check moving material's temperature?
3. In 2D surface plot, I found that material is not moving. I think this may be because Conjugate heat transfer and Moving mesh were not coupled. How can I check whether these are coupled?
Thanks.
Attachments:
2 Replies Last Post Feb 22, 2012, 4:13 p.m. EST
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Interesting question!
But wouldn't it be better to ask the hole Forum instead of just one person? ;-)
By the way a better subject help people to become aware of your problem.
Good luck
But wouldn't it be better to ask the hole Forum instead of just one person? ;-)
By the way a better subject help people to become aware of your problem.
Good luck
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi Jiyoung
Daniel is perfectly right, pls do not be personal in the Subject, it does not tell the FORUM users what it's all about. You can normally go back and edit that.
I'm not the Forum, probably I'm spending too much time here and answers too many times, hopefully not to often by giving bad advises. Anyhow, I'll have to slow down, I have got a couple of new projects and challenges to look after (with COMSOL, bien sûr, but not only)
And I hope that the other users do not hesitate to correct me when required, or answer too !
So w.r.t. your questions: certainly you should tweak the auto-remesh criteria to perhaps remesh earlier. For that you need to stop the solver and check the mesh quality to find out when to remesh. Note that the boundary mesh elements often tend to reduce the mesh quality as they are often thin and long, and not nice and "round". There are also other means , using the different mesh ALE methods, Winslow, Hyperelastic. Then you can also add some guidelines/boundaries. All this is better learned by following one of the "advanced meshing technique" courses of COMSOL, that is where I got many of the tricks on "how to", they are organised all over the world in regular intervals
If you solve for T you should be able to have/solve and measure T all over, mesh fixed or moving
Indeed coupling the physics, then deciding how to segregate, or not, the solver sequence is not trivial, and might require some trials. It's just to start and go on.
Also I would try to put the ALE physics first in the list (just drag it to the top), then recheck all BCs lower down, also for the other physics as this might change the "overrides" for you. normally you should read the node entries TOP down (first to last)
NITF is delicate to get to solve, it's a rather heavy physics combination already without ALE. And should you solve flow and T together ? segregated T first U thereafter ? or the opposite ?, or fully decoupled in separate solver nodes? For me no clear response, that depends among other on your RAM size, on the flow velocity, the heat diffusivity i.e all the flow invariants/constants Knudsen, Reynolds ....
--
Good luck
Ivar
Daniel is perfectly right, pls do not be personal in the Subject, it does not tell the FORUM users what it's all about. You can normally go back and edit that.
I'm not the Forum, probably I'm spending too much time here and answers too many times, hopefully not to often by giving bad advises. Anyhow, I'll have to slow down, I have got a couple of new projects and challenges to look after (with COMSOL, bien sûr, but not only)
And I hope that the other users do not hesitate to correct me when required, or answer too !
So w.r.t. your questions: certainly you should tweak the auto-remesh criteria to perhaps remesh earlier. For that you need to stop the solver and check the mesh quality to find out when to remesh. Note that the boundary mesh elements often tend to reduce the mesh quality as they are often thin and long, and not nice and "round". There are also other means , using the different mesh ALE methods, Winslow, Hyperelastic. Then you can also add some guidelines/boundaries. All this is better learned by following one of the "advanced meshing technique" courses of COMSOL, that is where I got many of the tricks on "how to", they are organised all over the world in regular intervals
If you solve for T you should be able to have/solve and measure T all over, mesh fixed or moving
Indeed coupling the physics, then deciding how to segregate, or not, the solver sequence is not trivial, and might require some trials. It's just to start and go on.
Also I would try to put the ALE physics first in the list (just drag it to the top), then recheck all BCs lower down, also for the other physics as this might change the "overrides" for you. normally you should read the node entries TOP down (first to last)
NITF is delicate to get to solve, it's a rather heavy physics combination already without ALE. And should you solve flow and T together ? segregated T first U thereafter ? or the opposite ?, or fully decoupled in separate solver nodes? For me no clear response, that depends among other on your RAM size, on the flow velocity, the heat diffusivity i.e all the flow invariants/constants Knudsen, Reynolds ....
--
Good luck
Ivar