A Caution message in AFT Impulse.

Full message is:

Assigned Flow at Junction X has a constant flow rate during the transient. During a transient the flow usually changes. This may not be an appropriate use of the junction.

An Assigned Flow junction fixes the flow at a boundary. When a transient occurs in the system, it is common to see all flows affected by the transient. This is a reminder that this junction may not be the appropriate junction to model a transient boundary condition. In general it is better to use Assigned Pressure or Reservoir junctions at boundaries. If there is a specific reason for using a fixed flowrate then this junction is the best way to do this.