Force required to seperate two plates apart

[Sunny Kumar]

Main Question or Discussion Point

If two plates of area A and seperation d contain liquid in between with angle of contact 0 degrees, then what is the amount of force required to pull the two plates apart???

How do we derive this??

 

[freireib]

Are the plates pulled apart quickly or very slowly. The "quickness" will be controlled by the capillary number.

For slow speeds the derivation will follow directly from the Laplace Young equation relating the curvature of the bridge surface to the pressure inside the bridge.

For high speeds this is a squeeze film and can be solved using the Navier Stokes solution and axi-symmetry.