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-   -   transient velocity for wall:UDF or Profile (http://www.cfd-online.com/Forums/fluent/43954-transient-velocity-wall-udf-profile.html)

Modisa March 1, 2007 12:51

transient velocity for wall:UDF or Profile
 
Hello,

I would like to know how it would be possible to define a transient velocity for the wall?

Thanks

Sujith March 1, 2007 14:49

Re: transient velocity for wall:UDF or Profile
 
yea..

you can give a velocity profile to the wall(DEFINE_PROFILE); where the profile is a function of flow time(CURRENT_TIME)

profile = f(CURRENT_TIME)

Modisa March 1, 2007 20:29

Re: transient velocity for wall:UDF or Profile
 
Hi Sujith,

Thank you for your quick response. The translational movement could be modeled by both profile and UDF. My problem is that my walls have both rotational and translational movements as a function of time. What is your suggestion for that?

Thanks


eos March 6, 2007 10:47

Re: transient velocity for wall:UDF or Profile
 
hi, i am working on the same thing as well rotational movement can be also done by cg_motion udf (i did iti for both tranlating and rotating body depending on time) but i am still working on the wall velocity calculations depending on the translational and rotational movements does anybody know how to set the velocity components depending on the node positions and the variables calculated in cg_motion udf? sorry i could not answer but instead ask new questions but thanks anyway

Modisa March 7, 2007 00:30

Re: transient velocity for wall:UDF or Profile
 
Hi, Could you please explain your question more. Do you mean each node of your geometry has a specific velocity?

eos March 7, 2007 08:30

Re: transient velocity for wall:UDF or Profile
 
hi, as i said the the mesh is moved by the rotational and translational motion. i defined this mechanism via cg but still i can't be sure of the wall velocity. the other users using fluent say that if you hook the cg motion to wall and fluid both then the wall velocity should be adjusted as it should be. (you know the velocity will have both x and y components due to rotation) that's the problem using define_cg_motion is enough to employ the velocities at the wall? thanks four your concern


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