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Hamish October 12, 2007 17:00

Dynamic Mesh - Ball in Cylinder
I am trying to learn more about the dynamic meshes in fluent, and have what I think should be an easy model to setup. I created and meshed a cylinder with sphere cut out of it, and created a zone at the sphere. I am confused what to do in the dynamic zone form under Motion UDF/Profile. I want to just have the ball move at a constant velocity for a given amount of time in an unsteady case. When I create the profile I do not see how to set this velocity. I looked in the tutorial, but they use a UDF, which seems very unnecessary for just a constant movement. Thank you in advance, Hamish

Venkatesh October 14, 2007 13:32

Re: Dynamic Mesh - Ball in Cylinder
When you want the motion to be constant to be constant velocity, you just use the GUI panel ... no need to use the UDF.

Hamish October 14, 2007 18:57

Re: Dynamic Mesh - Ball in Cylinder
When I just set the constant velocity in the boundary condition, I can get the solid ball to move, but the fluid mesh does not modify with it, is there a way I need to tell it how the ball is in contact with the fluid? Or am I going about this the completely wrong way? Thanks, Hamish PS Sorry if these are stupid questions, I have found myself out of my depth on this.

Venkatesh V October 15, 2007 15:51

Re: Dynamic Mesh - Ball in Cylinder
You have to tell the solver to what are the zones to be remeshed. In your case you can make a concentric cylinder aroud 5 or 6 diamaters bigger than the ball. And inform the solver to remesh the zone. I would suggest you to try the tutorial in Fluent.

I am independent freelance consultant. I would not able to help you more than that for free.

Thanks Venkatesh V

sunil October 26, 2007 04:03

Re: Dynamic Mesh - Ball in Cylinder
Hi Hamish,

For your problem (constant velocities), you can use profile files which are very easy to make and under-stand. When you will read profile file in your case then automatically you will get profile in motion attribute panel.

you can define any angular and linear velocities at any time with the profile file.....please check more details in fluent manual.


Sunil Damira

Hamish October 26, 2007 08:43

Re: Dynamic Mesh - Ball in Cylinder
Yes thank you I did end up using a profile, and it worked well.

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