Capillary action? Or not?

[nomaam22]

Hello:

I am a laymen when it comes to this topic so please excuse me if the answer to my question is apparent.

I am trying to phrase a certain problem which I can only technically describe as a form of capillary action.

The scenario is that I have a small diameter tube where air flows through under very low pressure. If there is a single drop of water in the tube the air flow is blocked. If the tube diameter is increased just slightly the water droplet no longer blocks the tube and the air will flow freely and the water will move out of the tube.

Could someone please help me describe this scenario using proper scientific terminology?

Thank you.

 

[cvg]

http://physics.about.com/od/physicsexperiments/a/surfacetension.htm

because of surface tension, the droplet will take a shape with minimum energy. size of the tube that will be blocked is also partially based on the viscosity of the fluid.

 

[mfgenggear]

nom

this is not capillary action. capillary action when to surfaces are such as two close fit part such as a plug pressed into a round hole.
it is then touched up with solder acid , & then heated & soldered. the solder is sucked between the surfaces. this is capillary action.

I agree with cvg this is a case of water surface tension, which will block the orifice. such as tube.

mfgenggear

 

[Compositepro]

Capillary action is an effect of surface tension. As cvg said the droplet will assume the minimum energy state. This shape will depend on the surface tension (samethig as surface energy) of the liquid, the surface energy of the tube wall, and the geometry of the tube. The cause for resistance of the droplet to move in the tube (regardless of whether it completely blocks the tube or not) is much more complex and will involve liquid viscosity, surface texture, energy of wetting versus energy of unwetting the surface.