[cwl6750084]

I am simulating (turbulent) air flow across a long slab (as shown in the figure). Due to the size of the problem, I am thinking of simulating only a thin layer in the centre of slab as shown. However, I am not sure what boundary condition should I put on the two sides of the control volume (the green surfaces). I tried using the outflow condition but Fluent returned the error that outflow BC cannot be use together with a pressure outlet BC.

Does anyone has any idea? Thanks in advance.

[cwl6750084]

Sorry, the figure was not attached.

Air Flow across a Slab.jpg

[LuckyTran]

Try symmetry or (my favorite) periodic boundary conditions.

The top red BC would better be a farfield BC rather than symmetry.

[cwl6750084]

Originally Posted by LuckyTran

Try symmetry or (my favorite) periodic boundary conditions.

The top red BC would better be a farfield BC rather than symmetry.

Aaarh, thank you very much. Actually, I tried using the far-field on the top surface. For some unknown reasons, the simulation crashed immediately upon solving, citing a segmentation fault error. I could not figure out how to resolve it and reverted to using symmetry over there as well.

By the way, the periodic boundary condition is not among the choices under BC. How can I set it?

Thanks.

[xXAhmedXx]

Originally Posted by cwl6750084

Sorry, the figure was not attached.

Attachment 58705

Hi there

what software you use to create the figure?

regards,

[cwl6750084]

Originally Posted by xXAhmedXx

Hi there

what software you use to create the figure?

regards,

I drew that in powerpoint.

[Fabio88]

I agree with Lucky Tran about periodic BC for the side walls.
Just be careful about the width of your domain. I would suggest to make a sensitivity analysis about the influence of the width of your domain to the final results.