Greetings! I have computed hydraulic models of my project. Everything is okay while computing. However, some of the discharges are above the initial source in the junctions and some of the velocities are out of the limit. Also some junctions have negative pressure. The water supply scheme is through gravity. Why this scenarios are happening ? If any one who is willing to help me, i am looking for your help.
With regards
Hello Samuel,
Negative pressure is observed when HGL reported is below the elevation of node, are there any valves in model, check for excessive headloss if yes.
Also check if the diameters are correct, check if large velocity is reported , check headloss in pipes, large headloss will lower down the HGL, resulting in negative pressures. See below link for more troubleshooting steps.
Troubleshooting negative pressures at pumps, junctions, & other node elements
Plot the profile of the line to understand what is happening. If there are pumps observe how pump is operating are there any notifications for pump? If the supply is from a reservoir or tank make sure the hydraulic grade (elevation) is high enough to supply the downstream demands and overcome the head losses in the pipes.
Regards,
Sushma Choure
Bentley Technical Suppport