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-   -   Handling boundary condition in Fluent (https://www.cfd-online.com/Forums/fluent/37747-handling-boundary-condition-fluent.html)

sak August 29, 2005 23:22

Handling boundary condition in Fluent
 
Hi Fluent users, i have a question, like in the geometry the periodicity between the boundaries is a mixed type of translation and rotation.

the boundaries are periodic but in fluent while dealing with boundary conditions, i cant select the boundary as both translation and rotation.

any idea as how to handle the conditions if the periodicity is both translation and rotation.

thanks in advance

Alex Zak March 24, 2013 07:22

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Originally Posted by sak
;123800
Hi Fluent users, i have a question, like in the geometry the periodicity between the boundaries is a mixed type of translation and rotation.

the boundaries are periodic but in fluent while dealing with boundary conditions, i cant select the boundary as both translation and rotation.

any idea as how to handle the conditions if the periodicity is both translation and rotation.

thanks in advance

Hi Sak!

I am intresting this problem too) My mesh in this image
SWIRL_STABE.jpg
Do anyone have ideas how create both translation and rotation periodic in fluent?

Thanks
Alex.

vasava March 25, 2013 04:33

I think you could write a UDF about mesh motion that has both rotation and translation. This along with options about 'mesh motion' in 'Cell Zone Condition' should resolve your problem.

deepthishan March 25, 2013 06:27

Total pressure at the outlet is more than inlet
 
hi
I am doing 3d modelling of a can combustor using k-e model.If I give mass flow inlet and pressure outlet or pressure inlet and pressure outlet I am getting total pressure at the outlet is more than total pressure at inlet.But there should be a pressure drop in reality in a combustor.Can u help:confused:?

jthiakz March 25, 2013 09:01

Pls check the location / methods (massflow weighted\area weighted average).
# what is inlet mach number (assuming subsonic)
# what are teh values of To,Ptot inlet To,Ptot outlet values
# what is the Ps in and out

deepthishan March 25, 2013 11:35

Its subsonic and pin=200000 and pout=212000 and the case is running well and giving results but in reality there should be pressure loss and here pressure is increasing..lets consider cold flow T=300k.In both cold flow and hot flow total pressure is increasing..

Alex Zak March 25, 2013 16:21

Hi Vasava!
Thanks for you reply!

But I am some questions about this problem
Is it better to use: mesh motion or frame motion in my case?
And how I am can set velocity (translation and rotation) mooved mesh or referense frame? Constants?


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