In the model above, I am expanding an existing water system to a new building. Per the results of hydrant flow tests, the available flow rate at R-4/PMP-4 is 1,060 gpm and at R-3/PMP-3 is 840 gpm (per a prior question, I am using an approximation method to model the hydrant flow tests from an article that was provided Bentley). My question: why would the flow in pipe P-7 go negative and why would the system try to pull more water from R-3/PMP-3.
See attached for two clips from the software.
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Hi Maria Rossi,
Without the model, it's tough to tell exactly why your pipe flow is going negative. But here is a Wiki article that explains some different causes - What does it mean if a pipe's flow is negative?
Please see if one of the suggestions helps explain this for your model.
You can upload a copy of your model for us to analyze if you can and choose to do so - just follow these instructions - Sharing Hydraulic Model Files on the OpenFlows | Hydraulics & Hydrology Forum
Please reply back to let us know if you found the cause in the first article or if you decide to upload your model for analysis.
Thank-you,Larry