Edit: please see duplicate answers as well
This iscould be a well-known hydrodynamic instability known as the Rayleigh-Plateau instability.
In short, liquids, because of surface tension at the liquid-gas interphase, tend to minimize their surface area. A liquid column of volume $V$ always has a larger surface area than $n$ droplets of volume $V/n$.
As it turns out the length at which point the liquid column will start to break up is found by the heuristic: $$\kappa R_0 \approx 0.697$$ where $\kappa$ is the wave number and $R_0$ is the initial radius of the column.