Understanding Absolute Viscosity - shearing stress

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SUMMARY

The discussion focuses on Absolute Viscosity and its relationship with shearing stress in Newtonian fluids. Absolute viscosity is defined as the tangential force per unit area required to move one plane relative to another at unit velocity, while shearing stress is the sideways force per unit area applied between fluid layers. The relationship between Absolute and Kinematic Viscosity is established, with Kinematic Viscosity being the ratio of Absolute Viscosity to fluid density. Units for Absolute Viscosity are expressed as g/(cm·sec), and for Kinematic Viscosity as cm²/sec.

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  • Understanding of fluid mechanics principles
  • Familiarity with Newtonian fluid behavior
  • Knowledge of viscosity concepts and measurements
  • Basic mathematical skills for calculating shearing stress
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  • Explore the physical implications of Absolute and Kinematic Viscosity
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Chadi B Ghaith
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Understanding Absolute Viscosity - shearing stress
Hi everyone,
I have found information about Absolute viscosity:

Coefficient of absolute viscosity is a measure of internal resistance. Dynamic (absolute) viscosity is the tangential force per unit area required to move one horizontal plane with respect to an other plane at an unit velocity when maintaining an unit distance apart in the fluid.

The shearing stress between the layers of a non turbulent fluid moving in straight parallel lines can be defined for a Newtonian fluid. Now my question is what is shearing stress and how to measure it? What is the relationship between Absolute and Kinematic Viscosity?
which units I can use for Absolute and Kinematic Viscosity?
 
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Chadi B Ghaith said:
Understanding Absolute Viscosity - shearing stress
Hi everyone,
I have found information about Absolute viscosity:

Coefficient of absolute viscosity is a measure of internal resistance. Dynamic (absolute) viscosity is the tangential force per unit area required to move one horizontal plane with respect to an other plane at an unit velocity when maintaining an unit distance apart in the fluid.

The shearing stress between the layers of a non turbulent fluid moving in straight parallel lines can be defined for a Newtonian fluid. Now my question is what is shearing stress and how to measure it?
Shearing stress is the sideways force per unit area that you have to apply to the plates. You measure the force required, and divide by the plate area.

What is the relationship between Absolute and Kinematic Viscosity?
Kinematic viscosity is equal to absolute viscosity divided by density
which units I can use for Absolute and Kinematic Viscosity?

Absolute viscosity: ##\frac{gm}{cm-sec}##

Kinematic viscosity: ##\frac{cm^2}{sec}##
 
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Chestermiller said:
Shearing stress is the sideways force per unit area that you have to apply to the plates. You measure the force required, and divide by the plate area.Kinematic viscosity is equal to absolute viscosity divided by densityAbsolute viscosity: ##\frac{gm}{cm-sec}##

Kinematic viscosity: ##\frac{cm^2}{sec}##
Thanks Chestermiller.

But I have another questions regarding shearing force & viscosity,

1) A fluid is flowing between two layers. Calculate the shearing force if the shear velocity is 0.25 m/s and has length 2 m and dynamic viscosity is 2Ns/m$^2$.

2) What's the physical meaning of these two viscosity ?
 
Last edited:
Chadi B Ghaith said:
Thanks Chestermiller.

But I have another questions regarding shearing force & viscosity,

1) A fluid is flowing between two layers. Calculate the shearing force if the shear velocity is 0.25 m/s and has length 2 m and dynamic viscosity is 2Ns/m$^2$.

2) What's the physical meaning of these two viscosity ?
I don't see any attempt on your part to solve Problem 1. For Item 2, what does your textbook say?
 

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