Hartmann number

Template:Short description The Hartmann number (Ha) is the ratio of electromagnetic force to the viscous force, first introduced by Julius Hartmann (1881Template:Spaced ndash1951) of Denmark. It is frequently encountered in fluid flows through magnetic fields. It is defined by:

$\mathrm{H}\mathrm{a}=BL\sqrt{\frac{\sigma }{\mu }}$

where

• B is the magnetic field intensity
• L is the characteristic length scale
• σ is the electrical conductivity
• μ is the dynamic viscosity

See also

• Magnetohydrodynamics

Further reading

• Template:Cite book Hartmann number is indicated by letter M in analogy with Mach number for aerodynamics.