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-   -   Boundary condition set up (http://www.cfd-online.com/Forums/fluent/96383-boundary-condition-set-up.html)

p3vd January 20, 2012 22:40

Boundary condition set up
 
Hi All,
I am working on my research project " prediction of wind loads on house roof during hurricance" where I have designed a house structure with 8 feet y-direction, 30 feet x-direction, 20 feet z-direction with roof socket of 2 inch and upstream, downstream set as 10 times volume of the geometry of house. I am confuse about setting the boundary conditions. I have taken velocity inlet and pressure outlet with house as wall but am confuse about the region between velocity inlet and wall of the house and from wall of the house to the pressure outlet, Can I take as outflow boundary condition for rest of the part?

mali28 January 23, 2012 14:06

Quote:

Originally Posted by p3vd (Post 340390)
Hi All,
I am working on my research project " prediction of wind loads on house roof during hurricance" where I have designed a house structure with 8 feet y-direction, 30 feet x-direction, 20 feet z-direction with roof socket of 2 inch and upstream, downstream set as 10 times volume of the geometry of house. I am confuse about setting the boundary conditions. I have taken velocity inlet and pressure outlet with house as wall but am confuse about the region between velocity inlet and wall of the house and from wall of the house to the pressure outlet, Can I take as outflow boundary condition for rest of the part?


Outflow boundary condition is only recommended when you flow is steady and stable at the outlet, even minor back flow in the outlet can cause convergence issues. It is better to use velocity inlet as the inlet boundary condition and pressure outlet as the outlet boundary condition.

Do you have another boundary between inlet and the wall of the house and from the house to the outlet?

p3vd January 24, 2012 14:29

Yes, I have bondaries beteween inlet to wall of house and from house to the outlet.
I have taken it as symmetry.
I m confuse regarding that part can I take it as symmetry or not?
Also when i am defining as a symmetry and when I am opening my meshing into fluent it gives me the error of "Warning: mesh is not detected correctly"
Also when I am using k-epsilon model, when I am running the calculation it gives me divergent result.
What to do with this problem?

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