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-   -   Problem with Dynamic remeshing (http://www.cfd-online.com/Forums/fluent/108871-problem-dynamic-remeshing.html)

teera11 November 3, 2012 10:00

Problem with Dynamic remeshing
 
Hello, everyone. Need your help.
I model the movement of top of the cylinder but the result is incorrect meshing (see figure 1,2). I have tried all modes in the Mesh Methods, but the result is the same.
http://img515.imageshack.us/img515/6925/24277562.gif
figure 1
http://img560.imageshack.us/img560/1328/75123472.GIF
figure 2
Please, tell me, how i can get this meshing (see figure 3).
http://img853.imageshack.us/img853/290/36871812.gif
figure 3
Thanks in advance.

cfd seeker November 3, 2012 14:45

It seems your mesh is very coarse

teera11 November 5, 2012 04:23

Quote:

Originally Posted by cfd seeker (Post 390070)
It seems your mesh is very coarse

Yes, my mesh is coarse. But is not a problem. The basic problem is incorrect remeshing after movement of the flange of the cylinder.

Marion November 5, 2012 06:21

Hi,
Have you used Local volume remeshing for the inside fluid volume and region face remeshing for the outside wall?
The cylinder wall should be "deforming" in the dynamic mesh settings. I think you need to define your geometry using the "Geometry definition" tab.
One last thing: be very carefull when you choose the "zone parameters": min, max length scales, etc.
Marion.

Marion November 5, 2012 06:22

Argh I just saw you put boundary prism layers in there - can you try moving the mesh without them?

Marion.

teera11 November 5, 2012 16:45

Quote:

Originally Posted by Marion (Post 390284)
Hi,
Have you used Local volume remeshing for the inside fluid volume and region face remeshing for the outside wall?
The cylinder wall should be "deforming" in the dynamic mesh settings. I think you need to define your geometry using the "Geometry definition" tab.
One last thing: be very carefull when you choose the "zone parameters": min, max length scales, etc.
Marion.

Argh I just saw you put boundary prism layers in there - can you try moving the mesh without them?

Marion.

Thank you for your advices, Marion!
I have some questions to you, if you mind. Should I "deforming" both wall and interior? Must I use UDF for definition geometry of interior?(figure 1,2)
http://img255.imageshack.us/img255/6964/30647832.jpg
http://img689.imageshack.us/img689/7948/26707705.jpg
I have also tried to model 2D process of movement of the flange, but i have the same problem(figure 3).
http://img839.imageshack.us/img839/894/70703228.jpg
Unfortunatly, I don't know how to moving the mesh without boundary prism layers.
If you have any advices else, I will very glad to hear them.
Thank you!

Marion November 6, 2012 03:13

Hi,

For the boundary layers --> When you do the mesh, just don't create the boundary layers.
For your 2D model--> you used quads, and it is not possible to use the remesh function with quads.

You don't need to define the geometry for interior, just keep the default parameters.

You have a max skewness of 1 - have you tried to put a lower value there?

Lastly, I think it is a good idea to start with 2D, to get a feel of what you are doing, just use tri instead of quads.

I hope this helps,

Marion.

Vidit Sharma December 16, 2012 10:34

Hi All..

Sir,
I am trying to rotate a 2D box or a 2D cup structure in Fluent using smoothing and remeshing. I am using tri mesh and as mentioned in Fluent Manual I am using smoothing and remeshing and also set the remeshing parameters from mesh info tab given in the remeshing menu. But the problem is that when i start simulation and it goes to first time step Fluent display "Updating mesh at time level N..." and here it stops and it happened alot of time and even waiting after a whole day it didnt worked. I also tried time step size from 0.01 to 0.000001 but it still show this problem.

Can you plz help in this case?

Thank u in advance

natalie January 24, 2013 17:05

Have you solved this problem with stretching cells adjacent to the moving boundary?


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