# Ericksen Number

Written by Jerry Ratzlaff. Posted in Dimensionless Numbers

Ericksen Number is a dimensionless number giving the ratio of the viscous to elastic forces.

## FORMULA

$$Er = \frac { \nu v l } {E}$$

Where:

$$Er$$ = Ericksen Number

$$\nu$$ = viscosity

$$v$$ = bulk fluid velocity

$$l$$ = length scale

$$E$$ = elasticity