Hi!
I'm having a hard time figuring out if flow rate decreases when water goes up a vertical pipe. I know that at some point when the water can't be pushed any higher due to P=pgh, the water stops flowing from the pipe. I also believe that due to continuity, all sections of the pipe should have the same flow rate no? I have seen many people calculate the second velocity for the Bernoulli equation using the continuity equation A1V1=A2V2 assuming constant flow rate. Is that really practical in real life though? Wouldn't a pump have to have a variable output or something to maintain the same flow rate while pumping water in a vertical pipe higher and higher? I guess I'm a little confused on the subject and I really hope someone can clear it up for me. Thank you for your help!!
1 answer
Now of course if the pipe is higher, the velocity will go down unless the pump works harder. That does not change the A1V1 = A2 V2 so V2=V1. It is just a different V at both point 1 and point 2 along the pipe. In other words less water flows through the higher pipe, everywhere along the pipe.