### Comments

4 comments

• Jason

Charles,

I think this problem is similar to the one in our Head Loss in a Submerged Discharge example where the flow rate is a function of the head that is a result of the calculated flow. This kind of problem requires a root solver to calculate the flow. Please have a look at this example and see if it helps. In the meantime, I do have one question: you mentioned that the sump water is pumped back into the sediment basin. So the water is just recycled from the sediment pond to the sump then pumped back into the sediment pond again?

-Jason

• Charles Ikenberry

Thanks, Jason.  I will check that example out - it sounds like that is the problem I'm having.  I tried using a Previous Value Element and a Looping Container, but couldn't get it to work.  To clarify, the "sump" is in the basin, which also has a main riser (outflow).  Water will be pumped from the sump to the main riser - that is how it leaves the basin (it is not recycled within the basin).  Thanks, again!

• Jason

Sounds good, Charles. The key is to iterate to a flow rate that converges based on the hydraulics through the outlet. In my example model, I start with initial guess flow values called "High" and "Low" then solve for head loss based on the middle value "Mid". Next, I solve for flow again using the energy equation (see ~Result). If ~Result is less than Mid, I reassign the High guess value to be Mid. Otherwise, I assign the Low value to be Mid. This process is iterated until convergence.

In your case, you will need to solve for flow rate through the system in a similar manner for this example to work in your case.

Let me know if you have problems or if you think it doesn't apply.

-Jason

• Jason

For those of you that might be following this topic, please note that a new version of the pipe flow model has been posted: https://support.goldsim.com/hc/en-us/articles/360001152308-Head-Loss-at-Submerged-Discharge

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