Marangoni number

The Marangoni number (Ma) is a dimensionless number named after Italian scientist Carlo Marangoni. The Marangoni number may be regarded as proportional to (thermal-) surface tension forces divided by viscous forces. It is – for example – applicable to bubble and foam research or calculations of cryogenic spacecraft propellant behaviour.

\mathrm {Ma} =-{\frac {d\gamma }{dT}}{\frac {L\Delta T}{\mu \alpha }}

γ: surface tension, (SI units: N/m);
L: characteristic length, (SI units: m);
$\alpha$ : thermal diffusivity, (SI units: m²/s);
$\mu$ : dynamic viscosity, (SI units: kg/(s·m));
∆T: temperature difference, (SI units: K).

Marangoni number

See also