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.

Please advice if I have some other option.

Regards

Zaqie

Switch massflow outlet to pressure outlet.
Indeed you have already defined a massflow at inlet
To your symmetry... it depends on your geometry (and also your BC), but "turbine blade" sounds like periodicity.
Check the help for understanding the difference

Boundary condition for turbine problem
 

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.

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