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-   -   Symmetry Boundary Condition for a fluid domain (https://www.cfd-online.com/Forums/fluent/67904-symmetry-boundary-condition-fluid-domain.html)

 Zaqie August 31, 2009 04:19

Symmetry Boundary Condition for a fluid domain

Hi

I am doing a fluent analysis on a water turbine blade. The bondaries I have used are as follows.

1. Velocity Inlet - at inlet
2. Mass flow outlet - at exit
3. Wall - at turbine blade
4. symmetry - at outer domain

I am fine with the first three, but I am not quite sure about the fourth one i.e is the symmetry condition. As far as I know symmetry condtion is like a wall but without a shear. But in practicality wont there be some outflow.

Regards

Zaqie

 -mAx- August 31, 2009 05:34

Switch massflow outlet to pressure outlet.
Indeed you have already defined a massflow at inlet
Check the help for understanding the difference

 Zaqie September 4, 2009 11:05

Boundary condition for turbine problem

1 Attachment(s)
Hi again

Please find attached a jpg image of 2d cross-sectional view of the turbine and its domain. I get the idea of the periodic boundary that can be used. But I am not sure of the boundary that is to be selected at the domain extends (rectangular box enclosed in the image). Any advice on that?.

Regards

Zaqie

P.S: I tried pressure far field condition and then found out that it can only be used for ideal gas equations, rendering it not suitable for my case.

 delfel September 4, 2009 17:57

Hello,

My vote is for a slip wall or a pressure outlet. I'd also put it as far from the foil as you can.

Cheers,
-sean

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