Rayleigh–Plateau Instability

Surface tension breaks a fluid cylinder into droplets
Weber Number We 0.30
Ohnesorge Oh 0.10
Noise Amp 0.010
Jet Velocity 2.0
The Rayleigh-Plateau instability: a cylindrical fluid jet of radius R is unstable to perturbations with wavelength λ > 2πR. Surface tension (We⁻¹) drives the instability; viscosity (Oh) damps it. The fastest-growing mode has k*R ≈ 0.697 (for inviscid jet). Droplet radius: r = (3R²λ/4)^(1/3).