  Pulsating jet is one of the common working modes in electrohydrodynamic
printing (EHDP) that process is highly affected by operating parameters and
material properties. In this paper, the processes of pulsating jet for liquids
with different physical properties were investigated using numerical
simulation. An electrohydrodynamic solver was established, and a charge flux
restricting step was adopted to ensure a realistic distribution of free
charges. Three various ejection regimes were observed in our simulations:
oscillating cone (OC), choked jet (CJ), and stable cone-jet (SJ). We found that
three dimensionless numbers relating to liquid properties determined the
ejection regime: the Ohnesorge number, Q0{\epsilon}r/Q, and Q0/(QRe). Based on
those dimensionless numbers, the roles of liquid properties on pulsating jet
(OC and CJ) were analyzed. In OC, the break of the jet is due to the
significant oscillation of the Taylor cone, which is mainly affected by
viscosity and conductivity. In CJ, the jet emission is terminated by the
excessive resistant force in the cone-jet transition region. For liquids with
low and medium viscosity, the dominant resistant force is the polarization
force or viscous force when {\epsilon}rRe is larger or smaller than 1,
respectively. For high viscosity liquids, the viscous force always becomes the
major resistance. These results further reveal the physical mechanism of
pulsating jet and can be used to guide its application.
