A Critical Warning message in AFT xStream

Full Message text is:

The maximum transient pipe Mach number (X) was higher than the estimate (Y). Results should not be considered accurate until the simulation is re-run with an estimated maximum pipe Mach number higher than the actual transient maximum.

 

The Mach number at some location in the pipes exceeded the Estimated Maximum Pipe Mach Number During Transient, which is defined in the Sectioning panel of Analysis Setup. This can cause instability in the solver and significant error in the results. The model should be re-run with the Estimated Maximum Pipe Mach Number During Transient set to at least 0.1 greater than the maximum pipe mach number encountered during the simulation.