Comments on: “Electrohydrodynamic drop-on-demand patterning in pulsed cone-jet mode at various frequencies” by Joonghyuk Kim, Hyuncheol Oh and Sang Soo Kim

The paper investigated describes the patterning of a series of drops generated by pulsed cone-jet electrohydrodynamic atomization. The authors concluded that when the voltage frequency is higher than the drop generation frequency, the drops formed and the spacing between one another are no longer uniform. The authors did not calculate the frequency where this transition occurs. A formula has been proposed that can be used to calculate this fulcrum frequency. It is noted that this relation only applies when the capillary is itself conductive. The proposed relation relies primarily on a formula proposed by Suvorov and Zubarev to calculate the Taylor cone formation time.