A Critical Warning message in AFT xStream

Full Message text is:

Pipe Mach number exceeded 1 during simulation.

 

AFT xStream is limited to sonic and subsonic flows, and cannot model flows exceeding Mach 1. However, the MOC calculations during the MOC Transient simulation can on occasion calculate velocities slightly above 1. This critical warning is shown by default when the Mach number in the pipes exceeds 1.0001. Users should examine results with this critical warning carefully, and recognize that results after Mach 1 is exceeded may be in error.