Capillary pressure in a tube


In a sufficiently narrow tube of circular cross-section of radius “a”, the interface between two fluids forms a meniscus that is a portion of the surface of a sphere with radius R. The pressure jump across this surface is related to the surface tension and the radius of the portion of the sphere.

Related formulas


ΔpCapillary pressure (Pa)
γSurface tension (N/m)
RRadius of the meniscus (m)