Surface tension occurs due to the tendency of liquid molecules to favor their own kind. Surface tension is important in fluid multiphase systems typically at small length and velocity

When to use

This tag should be used for fluid dynamics and statics, if surface tension will play a significant role in the physical process of interest. This significance can be roughly determined by looking at the following two dimensionless numbers:

The Weber number: $We=\frac{\rho u^2 L}{\gamma}$ which signals the relative importance with respect to inertial forces

The Capillary number: $Ca=\frac{\\mu u}{\gamma}$ which signals the relative importance with respect to viscous forces

When both numbers are small, surface tension will be dominant in the system.

Translated this means that the tag should be used for: fluid-fluid systems at small scales ($\mu$m to cm) and small velocities (typically $<1$ cm/s). Also flows with large surface tension gradients such as weld pools should wear this tag.

Adviced literature (starter level)

  1. Wikipedia: Surface tension
  2. Wikipedia: Contact angle
  3. Wetting at

Adviced literature (advanced level)

  1. Capillarity and Wetting Phenomena: Drops, Bubbles, Pearls, Waves by P.G. de Gennes et al, Springer 2004
  2. Snoeijer et al. (2013) Annual Review of Fluid Mechanics: Moving Contact Lines: Scales, Regimes, and Dynamical Transitions
  3. Quere et al. (2008) Annual Review of Materials Research: Wetting and Roughness
  4. Bonn et al. (2009) Reviews of Modern Physics: Wetting and Spreading