Viscosity Coefficient

on . Posted in Fluid Dynamics

Viscosity coefficient, abbreviated as \(\eta\) (Greek symbol eta), also called coefficient of viscosity or absolute viscosity, is a measure of a fluid's resistance to flow.  Viscosity is a fundamental property of fluids, and it describes how easily a fluid flows or deforms when subjected to an external force, such as shear stress.  Fluids with higher dynamic viscosity are more resistant to flow and are often referred to as "thicker" or "more viscous," whereas fluids with lower dynamic viscosity flow more easily and are considered "thinner" or "less viscous."

Understanding the dynamic viscosity of a fluid is essential in various fields such as fluid dynamics, engineering, physics, and chemistry because it influences the behavior of fluids in many practical applications, including the design of pipelines, lubrication of machinery, and the study of fluid flow in biological systems.


Viscosity Coefficient formula

\( \eta =  F_t \; l \;/\ A \; v \)    (Viscosity Coefficient)

\( F_t =  \eta \; A \; v \;/\ l \)

\( l = \eta \; A \; v \;/\ F_t \)

\( A =  F_t \; l \;/\ \eta \; v \)

\( v =  F_t \; l \;/\ \eta \; A \)

Symbol English Metric
\( \eta \)  (Greek symbol eta) = viscosity coefficient \(lbf - sec \;/\; ft^2\) \(Pa - s\)
\( A \) = area \(in^2\) \(mm^2\)
\( l \) = distance between the layers \(in\) \(mm\)
\( F_t \) = tangential force \(lbf\) \(N\)
\( v \) = velocity \(ft \;/\ sec\) \(m \;/\ s\)


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Tags: Coefficient Viscosity