I have problem with modeling side weir in the situation when diameter of the conduit changes for example from DN800 to DN300.
Side weir suppose to start working at crest elevation 97,55, but nothing happens when the water level in the conduit reaches this level. The water starts to overflow only at 97,7 only when water level reaches the maximum modeling point.
But when I change the diameter of the conduit to DN 800, so there is no change in the diameters in the profile line, side weir starts to work properly. If overflows as it should at elevation 97,30.
Please explain the hydraulics in these situations and why does side weir makes different effect in these two situations.
To add to Sushma's response - in some situations the numerical solver may not be able to properly calculated the flow split, so it could be that the adjustment to the diameter causes it to be stable enough to start working correctly. Are you using the Implicit or the Explicit (SWMM) solver? (check in the calculation options). You may need to use the SWMM solver with a small Routing Step for more stable results with conduit control structure, or adjust other calculation options. See the following articles for more guidance:
Using Start and Stop Control Structures for conduits and channels (see section "Numerical stability")
Troubleshooting unstable SewerGEMS and CivilStorm results using the implicit solver
Troubleshooting unstable SewerGEMS and CivilStorm model results using the Explicit SWMM Solver
Also in the first screenshot you have the top elevation of the side weir set only 150 mm above the invert, yet the "can surcharge" is set to False. Did you mean to set it to true?
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Thank You for the answers, I will get acquainted with the information in the links.