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: Shear Stress due to Laminar flow

  1. Feb 3, 2007 #1
    1. The problem statement, all variables and given/known data
    Oil of Density 888kg/m^3 and viscosity 0.8Pa*s is flowing in a horizontal pipe of diameter 0.15m. The local flow velocity at the centerline is 10m/s. find the shear stress exerted by the oil on the wall of the pipe.

    2. Relevant equations
    tau = -eta*(dv/dy)

    3. The attempt at a solution
    = -0.8*(10/0.075) = 106.7 Pa
    but the given solution is 213Pa, exactly twice my answer, what am I doing wrong? thanks
  2. jcsd
  3. Feb 4, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

  4. Feb 4, 2007 #3


    User Avatar
    Homework Helper

    As AlephZero stated, you should find a velocity function v(y) as a polynomial of degree 2 satisfying the given velocity condition in the middle streamline.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook