Hello,
I'm simulating a model with open channels. When I check with the profile, in one channel, most upstream CS shows high HGL value (see the attached image. It's more than 198.5 m).
The upstream channel is subjected to back flow, but based on the profile variation can not expect such high HGL. Appreciate if anyone can explain how can I overcome such model results.
BR
Nishadi
Can you confirm if it is first / starting point - cross section of open channel branch? What other notifications do you receive in the model on computing? Do you see flooding anywhere?
What Happens When the Water Level Exceeds the Top Elevation of an Open Channel?
Regards,
Sushma Choure
Bentley Technical Suppport
Hello Sushma,
this happens with the most upstream CS of the channel. CS invert is 197.540, GL is 197.84, HGL is 198.582. But as per the profile animation no flooding.
Regards
Hello Nishadi,
What solver are you using? If may be worth trying to use the troubleshooting steps for the Implicit or Explicit solver to see if there are any improvements.
Otherwise, you can graph the results or check the cross section properties for when this maximum occurs. Graphing may help determine when this occurs and if this is only a brief instability.
Other than that, we would likely need to see a copy of the model files.
Scott
Hello Scott,
that high HGL at the most upstream CS occurs when the model run as a whole, but when I isolate that part and simulate it, then there is no such high HGL in that CS. any advice how to tackle that.?
I have set solver parameters so that the continuity error is less than 5%.
Nishadi, try graphing the HGL at that element to see if there is a momentary "spike". Even though the continuity error is low, such instability could still occur and you may need to further refine the calculation options or try the Explicit (SWMM) solver. (see the tips here)
Also ensure you're using the latest version of SewerGEMS which is currently 10.03.04.53: Downloading OpenFlows Software
As Scott mentioned if you need further help we will need to see a copy of the model.
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.