1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bernoulli equation - pitot tubes

  1. Oct 28, 2014 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
    My thinking: since the pitot tubes measure the stagnation pressure (static + dynamics pressure) and the height of the tubes are the same. By Bernoulli's equation, the total pressure along a streamline is unchanged, therefore there is no pressure change between two tubes which gives h=0.

    I just want to check is my thinking correct or not.
    Thank you!
  2. jcsd
  3. Oct 28, 2014 #2


    User Avatar
    Homework Helper

    The speed of the airflow at 2 will be higher than at 1 so that P2 < P1
    so that h will be as indicated in the diagram - the water level higher
    on the left than on the right.
  4. Oct 28, 2014 #3
    but isn't that P only the static pressure? But in this case we also have to include the dynamics pressure as well, so the total pressure
    P+(p/2)V2 stay the same everywhere on the streamline?
  5. Oct 29, 2014 #4


    User Avatar
    Homework Helper

    Bernoulli's equation describes fluid in motion so that P is the pressure in the fluid.
    The pressure is transferred to the air and water in the manometer.
    The 1/2 ρ v2 term is the kinetic energy term of the equation
    while the P term is the energy of the pressure (per unit volume of the fluid) and the
    ρgh is the potential energy term of the equation.
    Last edited: Oct 29, 2014
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Bernoulli equation - pitot tubes
  1. Bernoulli's Equation? (Replies: 4)