Head within pipe system
Head within pipe system
(OP)
Hello,
We have modeled a sedimentiation pond with a 6" pipe outlet that discahrges 2500' downstream. We have about 40' of drop between the pond and outlet but we do have a few areas of low spots in the pipe (pipe sits on grade). We are trying to analyze if we have enough head to push the stormwater through these lowspots and to the outlet. Will Hydrocad do this analysis?
We have modeled a sedimentiation pond with a 6" pipe outlet that discahrges 2500' downstream. We have about 40' of drop between the pond and outlet but we do have a few areas of low spots in the pipe (pipe sits on grade). We are trying to analyze if we have enough head to push the stormwater through these lowspots and to the outlet. Will Hydrocad do this analysis?





RE: Head within pipe system
As far as the modeling, using the tube/siphon outlet option should provide a more accurate simulation than the typical culvert outlet.
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Head within pipe system
RE: Head within pipe system
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Head within pipe system
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Head within pipe system
RE: Head within pipe system
A tube/siphon uses the Hazen-Williams coefficient to calculate frictional losses (assuming the tube is full along it's entire length) plus orifice losses at the inlet. This procedure allows for variations in the slope, and even sections with a reverse slope, as long as there in an overall drop. The only parameters are the tube size, length, roughness, and elevation drop.
Culvert flow, on the other hand, assumes a uniform slope, but covers a wider range of inlet and flow conditions, including partial flow in the barrel.
For complete details please see the HydroCAD Owners Manual at www.hydrocad.net/hcmanual.htm
Since you have a very long conduit with variable slope, tube flow seems a better match to your situation. I assume the conduit will be flowing full - any air pockets could be problematic in such a long line. I suggest that you get some feedback on your situation in the storm/flood engineering forum. My comments are limited to the modeling issues under specific conditions, and not to the general operation or suitability of your proposed design.
Peter Smart
HydroCAD Software
www.hydrocad.net