Capillary Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

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.

\(\large{ Ca = \frac { \mu v }  { \sigma } }\)                 


\(\large{ Ca }\) = 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