Understanding Absolute Viscosity - shearing stress

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Homework Help Overview

The discussion revolves around the concept of absolute viscosity and its relationship to shearing stress in fluids, particularly focusing on Newtonian fluids. Participants are exploring definitions, measurements, and the relationship between absolute and kinematic viscosity.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to define absolute viscosity and shearing stress, asking how to measure shearing stress and the relationship between absolute and kinematic viscosity. Some participants provide definitions and units for both types of viscosity. Others raise questions about calculating shearing force and the physical meaning of the two viscosities.

Discussion Status

Participants are actively engaging with the concepts, with some providing definitions and units while others are posing further questions regarding calculations and interpretations. There is a mix of attempts to clarify concepts and explore deeper questions without a clear consensus on the answers.

Contextual Notes

Participants are discussing specific calculations related to shearing force and the physical meanings of viscosity, indicating a need for further exploration of these concepts. There is mention of textbook references, suggesting reliance on external materials for clarification.

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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