Homework Help: Gauge pressure/flow velocity

1. Mar 29, 2009

Stryder_SW

1. The problem statement, all variables and given/known data
Water at a gauge pressure of 3.8 atm at street level flows into an office building at a speed of 0.80 m/s through a pipe 5.4 cm in diameter. The pipe tapers down to 2.6 cm in diameter by the top floor, 20 m above (see figure here http://www.uploadgeek.com/share-85DD_49B54943.html [Broken]). Assume no branch pipes and ignore viscosity.
A). Calculate the flow velocity in the pipe on the top floor.
I have this, its 3.450887574 m/s

B).Calculate the gauge pressure in the pipe on the top floor.
*****Figured it out, I wasn't tracking units.*****

2. Relevant equations
I have been trying to use Bernoulli's equation. P1+(.5 pv12)+(pgy1) = P2+(.5 pv22)+(pgy2)

3. The attempt at a solution
So far solving for P2 in Bernoulli's equation and dividing by 101300(pa/atm). I have come up with 1.990429541 atm. for my answer. Unfortunately this is wrong, help would be greatly appreciated.

Last edited by a moderator: May 4, 2017
2. Mar 29, 2009

rl.bhat

So far solving for P2 in Bernoulli's equation and dividing by 101300(pa/atm). I have come up with 1.990429541 atm. for my answer. Unfortunately this is wrong, help would be greatly appreciate