How does changing the pressure subnetwork accuracy affect overall model results? I know it is the model convergence criteria set point.
Specifically, I am in the process of evaluating piping diameters for a force main replacement project. Currently my calculation options for pressure hydraulics are as follows. Outside of the replacement pipe limits, all other model parameters are the same.
Pressure Subnetwork Accuracy: 0.005 (i know the default is 0.001 but changed to 0.005 based on previous help received from Bentley.)
Pressure Subnetwork Trials: 100
Option 1 (10" DIP - ID of 10.2 after cement liner) - convergence was achieved with a relative flow change of 0.00498 (just under the limit)
Option 2 (10" DR 17 IPS - ID of 9.41) - convergence was not achieved. Pressure summary has a relative flow change of 0.00887.
Does this mean option 2 is not a valid option. If i upped the accuracy limit to 0.009 it would show convergence. But this seems like it is bad modeling practice. but i do not know how it actually impacts the quality of the model? Is there an upper accuracy limit to stay under?
Ignoring the scenario not converging, the pump run times and pipe flows and velocities are comparable.
Thanks,
Scott
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Answer Verified By: Scott Kampa