Stewart number

A dimensionless number, defined by the identity

where B₀ and ω₀ are the characteristic values of the magnetic induction and the velocity of the fluid; l₀ is the characteristic dimension; σ and ρ are the specific electrical conductivity and the density of the fluid.
Comment on terms. The dimensional variables appearing in the dimensionless numbers Ha, Re_M, Pr_M, and S are given in the SI system of units.