[Avni]

Hi guys, how can I write a UDF for an inlet mass flow boundary condition using another mass flow outlet condition.

Simultaneously , I want to calculate the mass flow from the 1st boundary condition and transfer it to the 2nd boundary condition I set.

[upeksa]

You can use both scheme and UDF.

For velocity inlet, for example, you can write:

(rpsetvar 'v_inlet (pick-a-real "/report/surface-integrals/mass-weighted-avg inlet () velocity-magnitude no"))

where "inlet" is the name of your boundary condition, and v_inlet the name of your scheme variable.

and in your UDF, use:
real your_variable = RP_Get_Real("v_inlet")

Best regards.