[hebe2u.]

Hi,

I'm simulating an unsteady pipe flow.
I have mass flow rate profile for the inlet boundary condition. It is fluctuating between negative and positive value.

However, the result of the simulation shows the flow enters the domain during the negative mass flow rate. That is, the mass flow rate inlet boundary condation just imposes the absolute value of the profile. Probably, because it is "inlet".

If so, how can I impose the negative mass flow rate at inlet?
Under the "Opening" condition, it is not possible to impose mass flow rate or velocity(Velocity components are available, but I don't have any data related.)

Please let me know your idea.
Thank you!

[Antanas]

Originally Posted by hebe2u.

Hi,

I'm simulating an unsteady pipe flow.
I have mass flow rate profile for the inlet boundary condition. It is fluctuating between negative and positive value.

However, the result of the simulation shows the flow enters the domain during the negative mass flow rate. That is, the mass flow rate inlet boundary condation just imposes the absolute value of the profile. Probably, because it is "inlet".

If so, how can I impose the negative mass flow rate at inlet?
Under the "Opening" condition, it is not possible to impose mass flow rate or velocity(Velocity components are available, but I don't have any data related.)

Please let me know your idea.
Thank you!

Pressure or Mass Flow specified inlet doesn't allow outflow. Velocity specified inlet does.