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!

Homework Help: Fluid Mechanic Integration

  1. Jul 19, 2010 #1
    1. The problem statement, all variables and given/known data
    For turbulent flow in a smooth, circular tube with a radius R, the velocity profile varies according to the following expression at a Reynolds number of about 10^5.

    Vx= Vxmax * [(R-r)/R)]^(1/7)

    where r is the radial distance from the center and Vmax the maximum velocity at the center. Derive equation relating the average velocity ( bulk velocity ) Vav to Vmax for an incompressible fluid.
    ( Hint: The integration can be simplified by substitution z for R-r )

    2. Relevant equations

    3. The attempt at a solution
    i don't know which equation i should integrate and how?
  2. jcsd
  3. Jul 19, 2010 #2
    I guess the average speed is defined as [tex]<v>=\frac{Q}{A}[/tex] where Q is the volume of fluid passing through the cross section of area A in 1 second. How do you find Q? :wink:
  4. Jul 19, 2010 #3
    i think working with volume rate is useless
  5. Jul 19, 2010 #4
    Okay, why and what do you think of the solution?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook