Velocity and other results fields in a Diversion pipe

  Applies To 
  Product(s): StormCAD, CivilStorm, SewerGEMS
  Version(s): 08.11.03.XX and greater
  Area:  Calculations, Results and Output
  Original Author: Jesse Dringoli, Bentley Technical Support Group

Problem

Velocity results show as zero for a conduit set as a Diversion.

Solution

When modeling a diversion in a conduit, diverted flow (based on the rating table) is passed on to the next downstream element. The GVF-Rational (StormCAD) numerical solver approximates the hydraulic grades (and thus velocities) through a profile of a diversion link with a Gradually Varied Flow backwater calculation based on the downstream HGL. Because of this, the "Velocity" result (which is the average velocity) may not be applicable. Instead, you would refer to both the "Velocity (in)" and "Velocity (out)".

An alternative option would be to change the average velocity method to "simple average" and then the "velocity" result will show the average between the velocity in and velocity out.

See Also

Modeling a flow split (diversion) with the SewerCAD or StormCAD numerical solver

Velocity Calculations and the Average Velocity Methods in SewerCAD and StormCAD

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