Explicit Solver limitations

Hello,

I am simulating a stormwater network (in sewergems) where I have channels, conduits, manholes, Ponds (3 nos), POS, Pumps. I can not simulate this in Implicit solver (as it takes hours and giving unstable results).

When I simulate in Explicit solver, seems it does not gives accurate results for the conduits. how much I increase the rainfall, the HGL does not exceed the manhole ring level. I just did a trial by increasing the manhole ring level by 1 m and then HGL reaching that ring elevation (or in between elevation. How can I adjust this issue?

BR

Nishadi

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  • Hello Nishadi,

    This is working as expected. Without ponding, the hydraulic grade will be at the rim. However, there will still be potential overflow. Check the manhole results field "Is Ever Overtopping?" If this set to true, there is flooding at the node and you will likely see some value in the "Flow (Overflow)" for certain time steps, as well as results for "Flow (Overflow Maximum)". Without some definition for the ponding at the top of the manhole, the solver cannot determine the depth above the manhole that the overtopping will occur, so it sets the hydraulic grade at the rim.

    If you want to see the hydraulic grade above an overtopping manhole, using some sort of surface storage is recommended. 

    Depending on what you are trying to model, you may want to look into the 2D Modeling feature available in the current release of SewerGEMS and CivilStorm.

    Regards,

    Scott

    Answer Verified By: Nishadi 

  • Thanks Scott. Will check the attributes that you have mentioned.

    BR

    Nishadi