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Water hammer

Dear Bentley;

Can I make water hammer analysis for a distribution network which has no tanks or reservoirs (it has junctions only with fixed demand) after the pump station. in case of yes we can do it using Bentley hammer, is there any difference between doing hammer analysis for distribution network with junctions only? than doing of the hammer analysis for transmission pipelines with tanks and reservoirs?.

another question. is there any command to split one pipe into number of pipes with equal spacing for example I have one pipe with length of 1000 m and I need to create junctions on this pipe at equal spacing of 50 m.

Regards

Eng. Sayed Ali

  • Sayed,

    If you think about it, you need a tank or reservoir both physically and mathematically. Physically, there needs to be some source of water. Mathematically, there needs to be a place to start the hydraulic grade line; otherwise the HGL just floats in space.

    To split a pipe with a junction, just place a junction along a pipe. The software will ask if you want to split the pipe. Just say yes.

    Tom

  • Dear Tom

    I think i did not explain my question well.
    I have source of water ( reservoir) and there is pumps which take water from this reservoir and it will distribute water to water distribution network which consist of many junctions with fixed demand ( only junctions and there is no tanks or reservoirs in down stream of pumps)

    Regarding the second question i want to split the pipe into 20 equal pipes by one command.

    I hope i explained well my questions
    Regards
    Sayed Ali
  • Dear Tom

    I think i did not explain my question well.
    I have source of water ( reservoir) and there is pumps which take water from this reservoir and it will distribute water to water distribution network which consist of many junctions with fixed demand ( only junctions and there is no tanks or reservoirs in down stream of pumps)

    Regarding the second question i want to split the pipe into 20 equal pipes by one command.

    I hope i explained well my questions
    Regards
    Sayed Ali
  • As long as you have a tank somewhere in the system, you should be fine.

    There is no single command to split a pipe into 20. Why would you want to do that? In most cases, placing demands at each end of the pipe is usually sufficient unless the flows change dramatically along the pipe. How much does the flow change along the pipe? Does that 1000 ft. pipe make up the entire system?

    Answer Verified By: Sushma Choure 

  • Regarding splitting pipes into segments of equal lengths in HAMMER - one thing to keep in mind is that HAMMER (unlike some other transient analysis software) will compute transient results along with the length of pipes, not just at the end nodes. If you view or animate a profile in the Transient Results Viewer, you will see this.

    If you're doing this in order to match up the wave speed with the timestep, you can use the Transient Timestep Options tool under the analysis menu to find a good balance between run time and accuracy (reducing the timestep to avoid excessive length or wave speed adjustments). More background in this here:

    http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/9401


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

    Answer Verified By: Sushma Choure