Stuart number

The Stuart number (N), also known as magnetic interaction parameter, is a dimensionless number of fluids, i.e. gases or liquids.

It is defined as the ratio of electromagnetic to inertial forces, which gives an estimate of the relative importance of a magnetic field on a flow. The Stuart number is relevant for flows of conducting fluids, e.g. in fusion reactors, steel casters or plasmas.

Definition

 * $$ \mathrm{N} = \frac {B^2 L_c \sigma}{\rho U} = \frac{\mathrm{Ha}^2}{\mathrm{Re}} $$


 * B – magnetic field
 * Lc – characteristic length
 * &sigma; – electric conductivity
 * U – characteristic velocity scale
 * &rho; – density
 * Ha – Hartmann number
 * Re – Reynolds number