# Capillary Number

Capillary number, abbreviated as Ca, is a dimensionless number representing the relative effect of viscous forces against the surface tension between a liquid/ gas or liquid/ liquid interface. It is the ratio of viscous forces to surface tension forces. The equations for Capillary Number and calculation are shown below.

\(\large{ Ca = \frac { \mu \; v } { \sigma } }\) Where: \(\large{ Ca }\) = Capillary number \(\large{ \mu }\) (Greek symbol mu) = dynamic viscosity \(\large{ \sigma }\) (Greek symbol sigma) = shear tension \(\large{ v }\) = velocity of the fluid |

Tags: Equations for Fluid