Open boundary condition
 

Hello,

I want to simulate an oscillating flow in a duct.

I set the inlet as velocity inlet with a oscillating (sinusoidal) velocity profile. In outlet I have tried both pressure inlet and pressure outlet but in both cases I encounter reverse flow warning in the outlet faces.

-Is it normal?
-Which one (pressure inlet or outlet) is more suitable for my case?
-Is there any other type of boundary condition more suitable for the zone with bi-directional flow?

Thanks... :)

still waiting for the answer, Thansk...

There is nothing abnormal about reversed flow, if everything else is correct with your simulation
There is also nothing wrong with getting a reversed flow warning at your outlet, it depends what you need out of your simulation
To get rid of the warning extend your domain further away from your domain outlet and set the outlet BC there.

Regards
Luke