Table 5.

Dimensionless numbers sometimes used when working with two-phase flows.

Non-Dimensional Parameters		Function
$\mathrm{Weber}\mathrm{number}\left(\mathrm{We}\right)$	$\mathrm{We}=\frac{\rho U^2{w}_1}{\sigma }=\mathrm{Re}\times \mathrm{Ca}$	Ratio between inertia and surface tension; Multiphase flow parameter useful in analysing droplets formation and thin-film flows.
$\mathrm{Laplace}\mathrm{number}\left(\mathrm{La}\right)$	$\mathrm{La}=\frac{\rho \sigma w_1}{{\mu }^2}=\frac{\mathrm{Re}}{\mathrm{Ca}}$	It is independent of external dynamics parameters, such as velocity, and only includes the properties of the fluids and geometric characteristics of the channel.
Deborah number (De)	$\mathrm{De}=\frac{{\tau }_c}{{\tau }_p}$	Rheology parameter quantifying viscoelastic effects [40]; ${\tau }_c$ is the relaxation time and ${\tau }_p$ the time of observation.