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-   -   Modelizing two infinite parallel planes (https://www.cfd-online.com/Forums/fluent/115563-modelizing-two-infinite-parallel-planes.html)

 kiurigan April 2, 2013 09:39

Modelizing two infinite parallel planes

I want to know if there is any trick to modelize infinite geometries in fluent like two infinite parallel planes in 2D?

 oj.bulmer April 3, 2013 11:08

You can do it with the use of symmetry and streamwise-periodic boundary conditions.

OJ

 kiurigan April 4, 2013 07:40

But I can't use symmetry because I have a pressure gradient (which ensures the flow) and I can't use the periodic boundary condition because the two planes are in different temperatures and the use of periodic boundary condition obligates that all wall boundaries must be at the same temperature!! (see documentation here:
https://www.sharcnet.ca/Software/Flu...hxfer-restrict)

 oj.bulmer April 4, 2013 08:32

Be careful with the interpretation of the words :)

1) Streamwise periodic conditions do allow temperature and pressure drop in streamwise direction. You need to select a domain length in streamwise direction such that these drops are same for the next domain of same length.

http://jullio.pe.kr/fluent6.1/help/html/ug/node337.htm

2) "Constant wall temperature" doesn't mean all walls should be at same temperature. It means on any particular wall, the temperature everywhere should be the same, i.e. uniform without any profiles. But the temperatures of the streamwise-periodic boundary conditions can vary:

https://www.sharcnet.ca/Software/Flu...c-hxfer-theory

3) I mentioned symmetry, since in 2D case with FLUENT, the domain itself becomes a symmetry boundary conditions, in whole perspective, with the boundaries perpendicular to the flow being streamwise periodic. In CFX, you have to use a thick domain to simulate the same 2D case, where you would use the symmetry boundary conditions to the boundaries parallel to the flow and streamwise periodic boundary conditions to the boundaries that are perpendicular to the flow.

OJ

 kiurigan April 4, 2013 09:51

Thank you so much. It seems that I misunderstood this sentence "all walls must be at the same temperature (profiles are not allowed)"!!

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