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Laminar flow in pipe

  • Thread starter foo9008
  • Start date
  • #1
678
4

Homework Statement


why the shaer stress ( tau) formula is given by μ(dv/ dy ) = μ(-dV / dR) , why there is a negative sign there ?

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The Attempt at a Solution

 

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Answers and Replies

  • #2
275
95
The negative sign is included because you are considering the velocity as a function of the distance from the center line of the pipe, not from the wall.
 
  • #3
678
4
The negative sign is included because you are considering the velocity as a function of the distance from the center line of the pipe, not from the wall.
why when we are considering the velocity as a function of the distance from the the wall , it's positive ? or we can also consider the distance from the wall as positive ?
 
  • #4
678
4
The negative sign is included because you are considering the velocity as a function of the distance from the center line of the pipe, not from the wall.
can we consider the distance from the centerline of pipe to wall as positive ?
 

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