Based on the law of continuity if there is a series of pipes with 10 nodes for example and there is no demand at any of the nodes on the pipe the flow that passes through the 1st node in that pipe series would be the same as that passing through the last node in that series.
But then say if node 5 in that same series of pipes has a demand. Then the flow that passes through the last node would then be the flow at the beginning of the pipe series minus the demand at node 5.
Or in other words when you assign a demand to a node that node then becomes a point where water is viewed by the model as being consumed.
Question?
Now say in reality the water is not consumed at node 5 but there is a branch downstream of node 5 with multiple customers which produces this demand at node 5. If it's the case that I do not need to know the pressures/pressure drops within the branch downstream of node 5 I could simply assign the demand associated with that branch to node 5 and eliminate that branch from my model right?
Or in other words what you need to consider when deciding whether or not to remove a branch is whether or not you will need to extract information (pressures) from that branch. If the answer is no you could pretty much remove that branch from the system as long *** you assign the branches demand to the upstream node right ?
Here is additional information if you are using WaterGEMS about tool Skelebrator to reduce branch pipes from your model.
Using Skelebrator to reduce the number of pipes in a model
Regards,
Sushma Choure
Bentley Technical Suppport
I do not have skelebrator i am using WaterCAD.