# Relative Viscosity

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Relative viscosity, abbreviated $$\eta_r$$, is the ratio of the viscosity of a solution to the viscosity of a solution used.

## Relative Viscosity formula

 $$\large{ \eta_r = \frac {\eta} {\eta_s} }$$

### Where:

 Units English SI $$\large{ \eta_r }$$  (Greek symbol eta) = relative viscosity $$\large{\frac{lbf - sec}{ft^2}}$$ $$Pa-s$$ $$\large{ \eta }$$  (Greek symbol eta) = viscosity of a solution $$\large{\frac{lbf - sec}{ft^2}}$$ $$Pa-s$$ $$\large{ \eta_s }$$  (Greek symbol eta) = viscosity of a solution used $$\large{\frac{lbf - sec}{ft^2}}$$ $$Pa-s$$

Tags: Viscosity Equations