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Upstream Line With No Flow

7 REPLIES 7
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Message 1 of 8
ryanhansen6265
2303 Views, 7 Replies

Upstream Line With No Flow

I have an upstream line that once carried a large amount of flow to the overall system, but has since been cut off due to a system re-route.  I would still like to use the upstream line capacity for the original system, however I cannot run the model because the line has no flow.

 

I currently have a manhole at the end of the line. Is there a way to run the model without adding any flow to the system?

 

Thank you

7 REPLIES 7
Message 2 of 8

Can you post the drawing or open and Autodesk Support request?  I think this is a know issue.  

Matthew Anderson, PE CFM
Product Manager
Autodesk (Innovyze)
Message 3 of 8

I am unable to upload the.stm file and I dont believe we have a support contract at this time.

Message 4 of 8

Are you on subscription?  What version of Civil 3d / Storm Sewers are you using?

 

Rename the file, replacing the STM extension to a TXT and it should attach.

Matthew Anderson, PE CFM
Product Manager
Autodesk (Innovyze)
Message 5 of 8

I apologize, we are on a subscription.  I was told otherwise by our tech department.  Civil 3D 2008 Hydraflow Storm Sewers Extension.

 

I have attached the file, Line 14 is where the issue occurs

 

Thank you

Message 6 of 8

ok, this isn't what I thought it was.  You actually have a line with no flow.  SS can not calculate the HGL of an empty line.  SS can run capacity only calcs, but your best bet would be to add an insignificant amount of flow to the system at that manhole, say a known flow of 0.01 cfs would not add too much to the system.

Matthew Anderson, PE CFM
Product Manager
Autodesk (Innovyze)
Message 7 of 8

That was my thought, however the low flow in line 14 causes the time of concentraition to increase due to the low velocity and long pipe travel time.  Either way, I think my best choice is to eliminate the node because adding flow that does not exist is not the answer.

 

Thanks for all of your help.

Message 8 of 8

If the line truly has no flow - eliminate it.  It appeared it was backpitched or much lower than the downstream pipe so that when the pipe flow was 0.01 cfs - the pipe had to surcharge to flow.

Matthew Anderson, PE CFM
Product Manager
Autodesk (Innovyze)

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