Polymeric fibers with diameters in the range from 50 nm to 5 mm are produced by accelerating a fluid jet in an electric field, in a process known as ‘‘electrospinning.’’ Here we show that an essential element of the process is a fluid instability, the rapidly whipping jet. The phenomena responsible for the onset of whipping are revealed by a linear instability analysis that describes the jet be...

A circular disc hitting a water surface creates an impact crater which after collapse leads to a vigorous jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in a single point halfway down the cavity. Two fast sharp-pointed jets are observed shooting up- and downwards from the closure location, which by then has turned into a stagnation point surrounded by a locally hyp...

We present the results of a 2-D numerical analysis of the stability of radiative supersonic cylindrical jets against Kelvin-Helmholtz instabilities. The numerical scheme employed is a PPM-type code, the boundary conditions are periodic on the longitudinal direction, i.e we adopt a temporal approach; the interface between the jet and the ambient medium is modeled by a smooth velocity and density...

We present three-dimensional direct numerical simulations of an hydrodynamical supersonic jet, comparing them to analogous results obtained in two dimensions. The differences seen between three-dimensional and two-dimensional jet evolution including faster evolution, enhanced mixing and larger jet momentum depletion, are interpreted in terms of specific physical differences between these two ca...