1. Not finding help here? Sign up for a free 30min 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!

Fluids and viscous flow

  1. Nov 5, 2007 #1
    1. The problem statement, all variables and given/known data
    Water (n = 1.00 10-3 Pa·s) is flowing through a horizontal pipe with a volume flow rate of 0.029 m3/s. As the drawing shows, there are two vertical tubes that project from the pipe. From the data in the drawing, find the radius of the horizontal pipe.


    2. Relevant equations

    Q = πR^4(P1-P2) / 8nL

    3. The attempt at a solution

    0.029 = πR^4(0.045) / (8*10^-3 * .7)

    solve for R, multiply by 100. However, i dont get the right answer...

    What am i doing wrong? this seems like such a straightforward problem
  2. jcsd
  3. Nov 5, 2007 #2


    User Avatar

    Staff: Mentor

    Is the differential pressure, (P1 - P2), in the formula given as the head (height or depth) of water (0.045 m), or is it pressure, in which case [itex]\Delta[/itex]P = [itex]\rho[/itex]g[itex]\Delta[/itex]h, where [itex]\Delta[/itex]h is the difference in heights of the water columns, i.e. 0.045 m.
  4. Nov 5, 2007 #3
    oh maybe it's pgh. let me give it a second go.
  5. Nov 5, 2007 #4
    yes i got it right. thank you Astronuc for the fast reply! I owe you :)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Fluids and viscous flow
  1. Fluid Flow (Replies: 2)