remeshing in Ansys CFX - help or tutorials needed
 

Hello All

I am currently trying to model a plate moving along a specified path in order to measure lift and drag forces/coefficients as it moves. I am doing this using Ansys CFX and specifying a moving mesh of a cylindrical subdomain which contains the plate. I use the cylindrical subdomain so that the mesh within that domain does not deform, instead only mesh in the outer domain deforms where the flow is not significant.

My issue is in the outer domain, the mesh deformation very highly skewed element and eventually negative elements which causes the simulation to crash.

I would like to use a remeshing controller during the simulation to remesh the outer domain while leaving the inside domain as is however I can not find any good tutorials explain how to do this. I have a very little bit of experience with ICEM MESH so if i need to use that, that is okay but i'd much rather use the CFX meshing to do this.

If anyone has any experience with using a User Defined remesh parameter can you please help guide me on how to set this up or could anyone point towards some good tutorials explaining how to do this.

Thank You,

DM

Hi Doginal,

I believe ANSYS has some examples on that, using either ICEM CFD or ANSYS Meshing as the remesher. You should contact your ANSYS representative and ask for these examples.

Cheers.

Thank you for your reply. I'm in the process of trying to get in touch with Ansys Support but i'm waiting to try to get an account set up first.

I have a couple of random questions.
Is it possible to combine a mesh from ICEM CFD with CFX-Mesher. If it is possible, I would like to mesh an outer domain with ICEM CFD and an inner subdomain with Ansys CFX.
From there I would remesh only the outer domain and leave the inner sub domain constant as the inner domain does not deform at all.

Hopefully that makes sense.

Thank You,

DM

There are two different answers to your question.

If you're working in ANSYS Meshing then yes, it's possible. Inside ANSYS Meshing you can generate an ICEM Tetra mesh in one body and any other meshing method on the other body. The resulting complete mesh will be conformal at the interface.

If you work on ICEM "standalone" (ie, not through Workbench) then it is still possible, but you won't get a conformal mesh at the interface. However that is not a problem for CFX. You can just set a domain interface and follow through with that option. Just be careful to set similar mesh sizes at the interfaces so that you get approximately the same number of nodes on each side.

That's about it.

I just read your first question again, and it came to me that remeshing is not needed on your case. If your mesh displacement is known beforehand, than you can just do a "dry run" to check at which timesteps your mesh becomes unacceptable. At that point you should generate a new mesh and restart your simulation using it. You can even use CFX's multiconfiguration feature to do the mesh switching automatically.

Hi,

I did the following tutorial a year ago explaining how to do this in CFX using ICEM.

http://www.edr.no/blogg/ansys_blogge...cfx_re_meshing


Klas Johansson, Ph.D.
Technical Consultant

EDR | Engineering Data Resources AB |
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hello, adeban, after remesh, my box always get back to the initial position! I don't know why? please offer me some help