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 named after Pierre-Simon Laplace and Indonesian physicist P. C. Suratman.^[1]

It is defined as follows:^[2]

\mathrm {La} =\mathrm {Su} ={\frac {\sigma \rho L}{\mu ^{2}}}

where:

Laplace number is related to Reynolds number (Re) and Weber number (We) in the following way:^[2]

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

^ Massey, Bernard Stanford (1986). Measures in Science and Engineering: Their Expression, Relation, and Interpretation. E. Horwood. ISBN 978-0-470-20331-6.
^ ^a ^b Balakotaiah, V.; Jayawardena, S. S.; Nguyen, L. T. (1999). "Studies on Normal and Microgravity Annular Two Phase Flows" (PDF). Proceedings of the Fourth Microgravity Fluid Physics and Transport Phenomena Conference. Retrieved 27 May 2024.