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-   -   rotation (http://www.cfd-online.com/Forums/fluent/110507-rotation.html)

krisipanikou December 12, 2012 16:36

rotation
 
Hello,
I want your advice.. :)
I am trying to simulate heat transfer in a natural convection problem. My cylinder can is on a rotating disc.. I don't get the results I want, so I am asking you: Do I have to use the Frame Motion option from Cell Zone Conditions in order to put the rotation speed and the Rotation-axis direction or I have to use the option Moving wall fron Boundary Conditions. Maybe both of them?

Thank you..

K.P

ghost82 December 13, 2012 09:50

you can use moving wall only if you have a surface of revolution (a cylinder is a surface of revolution); you can't use moving wall for the other cases (ex: rushton impeller, which is not a surface of revolution).

Daniele

krisipanikou December 13, 2012 11:14

Thank you Daniele !

K.P

ali_mehrabi69 December 14, 2012 07:05

rotation
 
I am modeling an air turbine in millimeter dimension. and have a problem with these rotation setting!
what should i do?
should i set a rotation velocity in cell zone condition for that region(the zone that is rotating)?or in wall rotation in boundary condition?
or both of them?

please answer me!!
Thank u

ghost82 December 14, 2012 07:18

Set an absolute rotational velocity to cell zone adiacent to your rotating turbine, then set the walls inside this cell zone to rotate with 0 relative velocity.

ali_mehrabi69 December 15, 2012 02:34

hey
 
yeah
i think you are true
but, how do i know (for design), how much of the cell zone, should be in rotating zone?maybe just near the turbine?or a bit far or ...?
how much?

tanx

ghost82 December 15, 2012 09:29

Quote:

Originally Posted by ali_mehrabi69 (Post 397650)
yeah
i think you are true
but, how do i know (for design), how much of the cell zone, should be in rotating zone?maybe just near the turbine?or a bit far or ...?
how much?

tanx

Theorically the results don't change in respect to the rotating zone size; your rotating zone must only include your rotating element.

Daniele


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