Good afternoon I recently made the delivery of a storm sewer model and observations arrived, and I would like to confirm the solution of these: 1. The Darcy-Weisbach equation is suggested for the calculation of friction losses in collectors. 2. Do the hydraulic analysis in both uniform flow and non-permanent flow. 3. It is suggested to contemplate the losses generated in the connection structures to wells.
Note: I look forward to your response, thank you in advance for so much collaboration
Hello Jefry,
Can you elaborate on what are you looking for to "confirm the solution"? Are you asking about confirming the results? I will try and answer (or ask further questions) based on the information you provided.
Jefry Novoa Acero said:1. The Darcy-Weisbach equation is suggested for the calculation of friction losses in collectors.
You can select the Darcy-Weisbach equation as the friction method for calculation. You can do this under the Calculation Options > Gravity Friction Method. Usually, for gravity flow the Manning's Equation is used so any specific reason why Darcy-Weisbach is suggested? Are the collector pipes partially / completely full (pressurized)?
Jefry Novoa Acero said:2. Do the hydraulic analysis in both uniform flow and non-permanent flow.
I think this means doing the analysis for "steady state" and "extended period analysis" (EPS). You can change the Calculation Type under Calculation Options, from "Steady State" to "Extended Period Analysis". You can then set the duration of your analysis (E.g. 24 hours).
Jefry Novoa Acero said:3. It is suggested to contemplate the losses generated in the connection structures to wells.
3. It is suggested to contemplate the losses generated in the connection structures to wells.
You can look into the different structure loss methods for the different solvers depending on what you are trying to model. How are the pipes connected to the wet-wells? Is there a significant drop (free fall of water) when entering the wet-well? You can model exit losses in the pipe to include the loss due to free fall or you can have control structures at the end of the pipe (entering the wet-well) to simulate the same. See the below article for details on the different types of structure losses;
Structure Loss methods supported by each solver
Let me know if this is what you are looking for. If not kindly elaborate the issue or point us to specific issues you are facing in modeling. A schematic or a model in such cases helps us understand the issue better and help you out.
Regards,
Yashodhan Joshi
Hi Yashodhan
I have doubts about point 2 and 3, they are the following:
2. At this point it suggests to me to change the type of calculation in the calculation options, but I am using GVF Rational for my storm sewers and this solution would not apply, or I am wrong.
3. I have already reviewed the different related methods in the link that you provide, I estimate to do tests with 2 of them to see which one is best applied to my model, what would be the route to use this solution? because they explain the type to me and not how to solve it
The GVF-Rational solver uses the gradually varied flow method to solve for the results in a system. You can find information on this in the Help documentation. There are some normal flow and normal depth results that are available, but these is mainly used to find capacity. You can find these results by looking for fields like Depth (Normal). Since these normal results are provided, you can use them in reports. But the profile results that you see will be based on gradually varied flow. See these links for details:
Why does the profile for the system appear to be at odds with the results for the capacity?
How are the profile descriptions derived in SewerCAD's GVF-Convex solver or StormCAD's GVF-Rational solver?
For the different headloss methods, information the HEC-22 methods mentioned in the link Yashodhan provided can be found the the HEC-22 manuals. The Absolute headloss method simply applies the value you enter. If you enter a 0.5 meter headloss, that will be the headloss on the structure. The Standard headloss method applies a coefficient to calculate the head loss based on the velocity head of the exit conduit. More information on this can be found in the Help documentation.
Scott