Abstract
A freely falling stream of weakly cohesive granular particles is modeled and analyzed with the help of event driven simulations and continuum hydrodynamics. The former show a breakup of the stream into droplets, whose size is measured as a function of cohesive energy. Extensional flow is an exact solution of the one-dimensional Navier-Stokes equation, corresponding to a strain rate, decaying like from its initial value, . Expanding around this basic state, we show that the flow is stable for short times, , whereas for long times, , perturbations of all wavelengths grow. The growth rate of a given wavelength depends on the instant of time when the fluctuation occurs, so that the observable patterns can vary considerably.
- Received 29 February 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.166001
© 2012 American Physical Society