WaterGEMS-Weird output in the model-Outflows without any apparent inflow source

Can somebody help me with the output above? If you look at the junction, water is flowing outwards without any apparent source of water. I was investigating the error in the model and looking at the dead ends to find out whats the issue.

Parents Reply
  • If demand is cut off from supply, water will be forced through the closed valves as the fixed demands impose a "known" in the equation and must always be solved as such (similar to the known HGL imposed at reservoirs for example). In this case you will indeed receive a user notification about disconnected demands as seen in this article: Disconnected Demand Nodes user notification when computing model

    However. I am not quite sure if the issue you are describing is due to this. You appear to be showing a case where flow is in reverse aware from a dead end demand. First, check the start/stop orientation of the pipe to make sure that the dead end node is the stop node. If you need to fix this, re-compute the model and check again. Customer meter demands are associated with the adjacent node as described here.

    If this does not help, check your user notifications and calculation summary to see if the network is unbalanced at the times during which you see the significant reverse flow. Also, check the "accuracy" calculation option. If a value larger than the default (0.001) is used, it can cause a higher magnitude of numerical noise in cases where flow should be closer to zero.

    If you still need help, please provide a copy of the model and identify any specific elements or steps to reproduce: Sharing Hydraulic Model Files on the OpenFlows Forum


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

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