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how to calculate shear stress in a pump

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Old   January 8, 2020, 10:34
Default how to calculate shear stress in a pump
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Hello everyone.

currently I'm simulating a pump design using CFX, I want to calculate shear stress in the fluid while passing through the pumps components.

I extracted the velocities (U,V and W) and used them to calculate shear stress

Tou (shear stress) = neu * (du/dy)


the problem is that I'm not sure if the method I used is correct or not

your suggestions please

best regards
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Old   January 8, 2020, 17:42
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This is only correct for Newtonian fluids. Also, CFX can output the velocity gradients directly, you don't need to calculate it. You might also need to consider the shear strain rate variables if that is relevant.
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Old   January 8, 2020, 22:56
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The variable "Wall Shear" is already computed and written to the results file for all the wall boundaries. There is no need to compute it separately, likely to make a mistake.
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Old   January 9, 2020, 07:02
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I don't want to calculate wall shear, since I want to know the influence of SS on fluid's particles. i need SS values along the pump.
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Old   January 9, 2020, 07:05
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Quote:
Originally Posted by ghorrocks View Post
This is only correct for Newtonian fluids. Also, CFX can output the velocity gradients directly, you don't need to calculate it. You might also need to consider the shear strain rate variables if that is relevant.
I performed a simulation, and used streamlines as a reference to draw chart for velocity (U,V,W). the data used in chart was exported in a .csv file that I used later to calculate the SS
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