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Thread: unbalancing due to 1 pipe

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  1. #1
    Member
    Join Date
    Dec 2016
    Posts
    56

    unbalancing due to 1 pipe

    I am preparing a mode
    The model run ok, balances after 32 iteartions.
    When I add 1 pipe connected to one node with demand zero, then the model does not balance. I increase to 200 iteration but still not working. WHat copuld be the problem?

  2. #2
    Forum Moderator

    Innovyze Employee



    Join Date
    May 2015
    Posts
    380
    Vladimir,

    It appears, something is causing the flows in that pipe to have difficulty converging. EPANET starts every pipe at 1 ft/s velocity so even a pipe with no demands has a non zero flow in it initially.

    Try adjusting your simulation options as follows to get convergence.

    General Tab:
    Trials: 200
    Accuracy: 0.001
    Unbalanced: Continue
    Extended Run: 50
    (click if need larger image)
    Simulation Options - For Convergence.jpg

    Advanced Tab:
    Status Check Frequency: 2
    Max Status Check Iteration: 10
    Relaxation Factor: 0.6
    Damping: 0.01 (i.e. at 10X your accuracy on the general tab)
    (click if need larger image)
    Simulation Options - Advanced.jpg

    This should help it converge and resolve your issue.

    If it still fails to converge make sure to set your report options to show a full status report and warning messages as this will tell you more about why it is having issues:
    (click if need larger image)
    Full Report with Warning Messages.png

    If you still have difficulties please let us know.

    Patrick Moore

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