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Homework Help: Viscosity finding the velocity at a point

  1. Dec 18, 2013 #1
    w1. The problem statement, all variables and given/known data

    water at 20 degrees celsius is flowing in a horizontal pipe is 20 m long. The flow is laminar and the water completely fills the pipe. A pump maintains the gauge pressure of 1400 pa at a large tank at one end of the pipe. the other end of the pipe is open to the air. the viscosity of water at 20 degree celsius is 1.005 poise

    a) The pipe has diameter of 8 cm what is the volume flow rate

    b) what gauge pressure must the pump provide to achieve the same volume flow rate for a pipe with a diameter of 4cm

    C) For pipe in part a and the same gauge pressure maintained by the pump what does the volume flow rate become if the water is at 60 celsius[at which the viscosity is 0.469 poise
    2. Relevant equations

    3. The attempt at a solution

    The viscous force is -na dv/dx.

    besides that i dont really have a clue what to do..
    please help and thank you!
    Last edited: Dec 18, 2013
  2. jcsd
  3. Dec 18, 2013 #2
    Have you ever heard of the Hagen Poiseulle equation (I'm not sure of the spelling)? If not, find out about it.
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