This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

50% closed valve in SewerGEMS

ref: https://communities.bentley.com/products/hydraulics___hydrology/f/haestad-hydraulics-and-hydrology-forum/78453/valve---sewergems 

Hi Jesse,

Is it possible to model a valve that is 50% closed in SewerGems using this process? Or possibly a pipe that is 50% open? In the SewerGems User Guide, there is a lot of information on using the Controls and Controls Sets Tab, but only using the GVF-Convex Solver; can the EPASWMM Explicit solver still be used?

Thank you,

Ryan

Parents
  • Hello Ryan,

    I have split your post to a new thread. 

    It sounds like you are using the Explicit (SWMM) numerical solver? Is this a valve on a pressure pipe or a conduit? (gravity pipe)

    If the valve is in a static position and does not change during the simulation, you can adjust the minor loss coefficient in the properties of the pipe where the valve is located, add a short, small diameter pipe, or possibly an orifice conduit control structure set to the diameter of the closure.

    If you need to adjust the valve position during the simulation based on some logic (or based on time), you could use SWMM control sets to adjust the size of an orifice control structure on a conduit. The "Control sets" that you saw related to the GVF-Convex solver may have been the Control Sets tab of the Controls ("logical controls") manager, from Components > Controls. This is separate from "SWMM Control Sets". 

    Here is an article that explains the differences between the different ways of defining controls in SewerGEMS: Pump On/Off Elevations vs. Logical Controls vs SWMM Control sets


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

    Answer Verified By: Ryan Haller 

  • Hi Jesse,

    That is correct, I am using the Explicit (SWMM) numerical solver for gravity fed conduit.


    The valve would be in a static position, therefore I think my best option would be to adjust the short pipe's diameter to mimic half of the cross sectional area of the full pipe, and adjust the minor loss coefficient. I was unsure if there was a different approach that could be taken.


    Thank you!

    Ryan

  • Hi Ryan,

    Yes, since there isn't an explicit valve element, the approximation using a small diameter valve, or a minor loss coefficient, would probably be best. 

    Generally speaking whenever you need to model something that does not have an explicit element type, you can think about what happens hydraulically (a headloss across the valve in this case), then use an existing feature/function to mimic that effect, (headloss from minor loss coefficient, reduced diameter or orifice control structure) or make a conservative assumption. If unsure, use a sensitivity analysis to determine the impact that it has on the overall "answer" that you need from the model. For example you could try both the diameter and minor loss approach (and the orifice control structure approach, too), then see if the results differ by much between these approaches. 

    See: Modeling devices and components that are not explicitly available as an element


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

Reply
  • Hi Ryan,

    Yes, since there isn't an explicit valve element, the approximation using a small diameter valve, or a minor loss coefficient, would probably be best. 

    Generally speaking whenever you need to model something that does not have an explicit element type, you can think about what happens hydraulically (a headloss across the valve in this case), then use an existing feature/function to mimic that effect, (headloss from minor loss coefficient, reduced diameter or orifice control structure) or make a conservative assumption. If unsure, use a sensitivity analysis to determine the impact that it has on the overall "answer" that you need from the model. For example you could try both the diameter and minor loss approach (and the orifice control structure approach, too), then see if the results differ by much between these approaches. 

    See: Modeling devices and components that are not explicitly available as an element


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

Children
No Data