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Shear Stress due to Laminar flow

  • Thread starter ice87
  • Start date
  • #1
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Homework Statement


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.


Homework Equations


tau = -eta*(dv/dy)


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
 

Answers and Replies

  • #2
AlephZero
Science Advisor
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  • #3
radou
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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.
 

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