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Problem Description
My scenario is not converging on a solution when once computed. I am getting a message in the calculation summary that Convergence is NOT achieved.
The calculation solver was not able to converge on a solution given the number of traversals of the network and/or other unresolved user notifications
For subscribers, the latest version and/or patch set can be downloaded by following these instructions:
http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/8175.aspx
In the user notifications dialog box you can double click on each notification and if it relates to a single element you will be brought directly to that element in the drawing pane. If there are many of the same type, right click on one of the user notifications and choose "select all elements with message id...."
Open the calculation options for the current scenario (Analysis > Calculation Options)
Try increasing the number of network traversals. Start with a large number like 50. If that doesn't work try 100. If that doesn't work then there may be data entry issues or something else wrong with the model. If careful review does not surface the root cause, contact technical support or post on the Hydraulics and Hydrology forum. If 100 does work then increase the number until you find the lowest number that still allows the model to converge.
If you're experiencing Non-convergence and your model is severely undersized, with significant flooding occurring, please note that this can often be the cause of non-convergence. This condition makes it more difficult for the solver to converge. More recent versions of the product handle this situation a bit better when increasing the max trials option mentioned above, but it is worth considering the limitations regarding flooding with the GVF-Rational numerical solver. The HGL will be reset to the rim elevation and the flow will continue in the pipe, whereas in the real system some of the flow will be lost. See the article below for more on this.
Different results when changing Maximum Network Traversals
Understanding how Maximum Traversals help with non converging models
Why is the HGL reset to rim elevation for flooded structures?