Analysis Report

[yss]

After I perform run analysis, at the end of the report is shown a title: Highest Flow Instability Indexes, and it list few links with numbers in brackets. What does this really mean?

[Chris Maeder]

StormNET computational method that was developed, allows us to track the model stability for each element. Then, at the end of the simulation, we report back the model stability for those elements that have the most instability as a percentage of the entire model stability.

This allows you, as the modeler, to review those "unstable" elements in the graphical output to see if they are appearing to be accurately representing the stormwater flow. You can then decide if these elements input data should be redefined inorder so that the model can become more stable. Alternatively, you can change the analysis options to get the model to run more stable.

If you are having any problems with your model and you need help, please feel free to contact our technical support staff for assistance. That is what they are here for.

Sincerely,

Chris Maeder, M.S., P.E.
Senior Technical Engineer
chris.maeder@bossintl.com

[yss]

I have since made the time step smaller and the report has generated the result that all links are stable.

But what does it mean with the numbers in the brackets before I did the change on the time step? The copy of the end part of the result is as below. If this shows that something needs to be changed, then where can one really start besides the analysis options? Does the number in the brackets indicate something as to give us some hints where we should modify our model?

********************************
Highest Flow Instability Indexes
********************************
Link Con-11 (11)
Link Con-10 (9)
Link Con-22 (9)
Link Con-20 (8)
Link Con-23 (8)

[Chris Maeder]

A Flow Instability Index is computed for each non-pump link. It counts the number of time steps in which the link's flow is either higher or lower than the flows at the previous and next time steps. The Status Report lists the links with the five highest indexes.

Sincerely,

Chris Maeder, M.S., P.E.
Senior Technical Engineer
chris.maeder@bossintl.com