Inflow at Outflow Boundary Condition-AcuConsole 21 CFD

avb
avb Altair Community Member
edited June 2022 in Community Q&A

I am trying to run my CFD model but am getting this error of "Inflow at Outflow Boundary Condition"

I have applied inlet flow rate value and at  Outlet pressure of 0 as boundary conditions.

 

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Answers

  • acupro
    acupro
    Altair Employee
    edited June 2022

    This warning indicates there is flow entering at what is typed as outflow.  Then it gives the mass flow rates for flow entering and leaving.  In this case it looks like the exiting flow is 10X the entering flow.  Sometimes this will 'wash out' as the run proceeds with flow only exiting those outflow boundaries.  Often if there is a lot of 'action' in the flow just upstream of the exits, extending the domain so the outlets are farther away can help.  Sometimes the extension needs to be added, along with a contraction towards the outlet, so the flow accelerates a bit into the outlet.

    If these don't help, and reverse flow continues, you may want to activate backflow conditions on those outflow boundaries, and specify the conditions (usually turbulence quantities and/or temperature) for any flow that enters.  Maybe start with exiting average (any entering flow has the same average value as the exiting flow).

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