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Dear friends,

I am a little bit confused by pressure boundary conditions and really appreciate if anyone can help me with this. In FLUENT User's Guide (Open Chanel Flow 23.3.9 section), it is mentioned that using Pressure inlet and Pressure outlet together is ok, while as I know the problem is not mathematically well-posed and is overdetermined when we use SIMPLE algorithm.

What if we use Coupled algorithm instead of SIMPLE?.

The other question is that when we face a problem that pressure boundary conditions (at inlet and outlet) are the correct ones. For instance, if we have an unsteady pipe flow with deposition what would be a proper BC for inlet? ( due to deposition we would face an increasing flow blockage inside the pipe and increasing pressure drop leads to the mass flow reduction). What would be the best BC for such a problem?

Thanks,

Best regards,