Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

U tube manometer

  1. Nov 27, 2012 #1
    I have been told to calculate the pressure drop between two points in a pipe carrying water using a U-tube manometer. I understand that the pressure drop (P1 - P2) is given by pgh and that h is the difference in manometer fluid levels and g is gravity, but is p the density of the manometer fluid or the water flowing through the pipe?
  2. jcsd
  3. Nov 28, 2012 #2
    Exactly, p1-p2 = gh(density(manometer fluid) - density(water))
  4. Nov 29, 2012 #3
    In the case im referring to, the manometer fluid has a lower density than the water. For a pipe, is the pressure drop measured using a utube manometer simply ρmanometergh?
  5. Nov 29, 2012 #4
    it is not a good idea to use a fluid of lower density in manometer than the density of fluid in the pipe. a higher density fluid is used to make measuring instruments smaller. for example, mercury will require a space 13.6 times smaller than water for same pressure rise or drop.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook