Capillary Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Capillary number, abbreviated as Ca, 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.


Capillary number calculator



Capillary number formula

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


 Units English Metric
\(\large{ Ca }\) = Capillary number \(\large{dimensionless}\)
\(\large{ \mu }\)  (Greek symbol mu) = dynamic viscosity \(\large{\frac{lbf-sec}{ft^2}}\) \(\large{ Pa-s }\)
\(\large{ \sigma }\)  (Greek symbol sigma) = shear tension \(\large{\frac{lbf}{in^2}}\) \(\large{Pa}\)
\(\large{ v }\) = velocity of fluid \(\large{\frac{ft}{sec}}\) \(\large{\frac{m}{s}}\)


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Tags: Fluid Equations Calculators