Originally Posted by **koytos** Hello friends;
i want to solve the problem about surface tension and dropping. i find a equation on __http://planetcalc.com/2296/ __ and i enter this formulato excel. But i dont sure this formula is true __.__ http://picpaste.com/AdsAe_z-km3N3Ktc.jpg
for water :
if pipe outlet diameter is 9,45mm (or less) no dropping occuring cause of surface tension force.
for oil :
if pipe outlet diameter is 7,43mm (or less) no dropping occuring cause of surface tension force. |

I get different results: R = 3.34 mm for water and 2.63mm for oil. I think in your Excel calculation you forgot the 2 in the denominator of the equation.

And the interpretation of R is it is the maximum size of pipe that will allow dripping, as opposed to continuous flow. For pipes of smaller radius you get drops, for pipes of larger radius you get continuous flow (according to the author).