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1. how to find the shear rate equation from the velocity profile equation?
I know the velocity profile equation (for laminar flow in a circular pipe) is:

uaverage = umax ((1 - r2)/R2)

and I know the shear rate= shear stress/viscosity

finding it difficult to relate the two?

The specific equation i'm dealing with is:
u = 9 [(1 - rr)/16]

Would appreciate any help :/
Last edited by Sifr; 19-07-2012 at 18:56.
2. Re: how to find the shear rate equation from the velocity profile equation?
I don't know.
3. Re: how to find the shear rate equation from the velocity profile equation?
Are you asking for the wall shear stress?
4. Re: how to find the shear rate equation from the velocity profile equation?
No the shear rate!
5. Re: how to find the shear rate equation from the velocity profile equation?
help
6. Re: how to find the shear rate equation from the velocity profile equation?
http://en.wikipedia.org/wiki/Shear_stress

Look at "Shear stress in fluids". Shear stress is defined as the viscosity multiplied by the rate of change of the velocity in a direction perpendicular to its velocity. Verify in your head that this makes sense.

That equation should be all you need. For a fuller treatment see the Navier-Stokes equation.