Coefficient of Viscosity

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Coefficient of Viscosity

Coefficient of viscosity ( $$\eta$$ (Greek symbol eta) ) (also called viscosity coefficient) is the tangential friction force required to preserve a unit velocity gradient between two parallel layers of liquid of unit area.  The greater the coefficient of viscosity the greater the force required to move the layers at a velocity.

Coefficient of Viscosity Formula

$$\large{ \eta = \frac { Fl } { Av } }$$

Where:

$$\large{ \eta }$$  (Greek symbol eta) = coefficient of viscosity

$$\large{ A }$$ = area

$$\large{ F }$$ = tangential force

$$\large{ l }$$ = distance between the layers

$$\large{ v }$$ = velocity

Solve for:

$$\large{ F = \eta \frac { Av } { l } }$$