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:
Laplace number is related to Reynolds number (Re) and Weber number (We) in the following way:
- Ohnesorge number - There is an inverse relationship, , between the Laplace number and the Ohnesorge number.