Laplace number

The Laplace number (La), also known as the Suratman number (Su), is a dimensionless number used in the characterization of free surface fluid dynamics. It represents a ratio of surface tension to the momentum-transport (especially dissipation) inside a fluid.

It is defined as follows:



where:
 * σ = surface tension
 * ρ = density
 * L = length
 * μ = liquid viscosity

Laplace number is related to Reynolds number (Re) and Weber number (We) in the following way:


 * $$\mathrm{La} = \frac{\mathrm{Re}^2}{\mathrm{We}}$$