Learning Forum

[Zari]

Hi,

I am setting a 2D-axisymmetric-swirl model. The geometry is a cylinder with two annular co-flow inlets that are somewhere in the middle of the cylinder. Both inlet gases are air, and the study is about flow fields and velocity components.

One end of the cylinder is the outlet boundary, and the other end is open. My question is about this open boundary. How should I set this boundary type in the model? It cannot be a wall, since it was open during the experimental measurements, so that air from the room could flow from that boundary. It cannot be an outlet, since then the solver will try to force the fluid to exit from this boundary.

What do you recommend for type of this boundary, and or settings? How about considering an air inlet there (from the room) with a small velocity magnitude that does not disturb the main flow?

Best regards,

Zari

 

[ansysuser]

Use a pressure outlet with a 0 gauge pressure for your "open boundary."  Fluent will allow backflow through a pressure outlet with no problem and it will not try to force fluid out.  Be sure to specify realistic backflow conditions. See the documentation below.

 

https://www.sharcnet.ca/Software/Fluent6/html/ug/node234.htm

[Keyur Kanade]

for flow you will require pressure gradient. 

in your case i can see that both ends you are maintaining same pressure. 

please use velocity inlet. 

please go through boundary condition basics in help manual. 

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