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-   -   How to set boundary condition in Fluent for the fo (http://www.cfd-online.com/Forums/fluent/42818-how-set-boundary-condition-fluent-fo.html)

Peiyong November 9, 2006 20:59

How to set boundary condition in Fluent for the fo
 
How to set boundary condition in Fluent for the following problem?

I am modeling the flow field around a rotating porous sphere with gas blowing out from the sphere surface. I have trouble setting up the boundary condition in Fluent. If I set the sphere surface to WALL boundary, I can not set the blowing velocity boundary condition. Vice verse, if I set the VELOCITY INLET boundary, It does not reflect the no-slip boundary condition at the sphere surface. What should I do? Any suggestion is welcome. Thank you. My contact is guojixinwen@hotmail.com


Eirik November 10, 2006 12:44

Re: How to set boundary condition in Fluent for th
 
Hm, interesting problem ... I can see a couple of ways that might get this done.

- You could define the outermost part of the actual sphere as a porous zone, and then have an inlet at the inside of this region. Set reasonable porosities for the sphere, use Fluents MRF model and of you go. You can even use the physical velocity formulation to get the acceleration terms.

- The other alternative would be to use a wall boundary and add mass and momentum sources in a region just ouside this wall. Requires a small UDF to add the correct radial momentum source.

Good luck.

- Eirik


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