Setting velocity UDF at outlets
 

I have a coronary artery and I am trying to implement a UDF of pressure in the inlet (pressure-inlet type) and a velocity profile in the outlets (mass-flow-outlet type). I understand that velocity and mass flow rate are different things, but the profile shape is the same (just different magnitudes).


This approach is inspired by Fig. 4 of an article (https://doi.org/10.1080/10255842.2014.921682).


I can implement the inlet pressure, but I cannot define the outlet velocity... the closest is mass flow rate which I selected.


When I run the calculation, Fluent returns the following error:


Error: / (divide): invalid argument [1]: wrong type [not a number] Error Object: inf.



I have tried doing the opposite (inlet velocity and outlet pressures) and there are no errors...



Any help? Thanks in advance

Not sure what your error is. Check your UDF. But you can specify the velocity if you use a velocity inlet type BC at an outlet. The BC type may be named an inlet but it is a fixed velocity constraint.