Characterisation of pulsed discharge in water^*

¹ Centre for Plasma and Laser Engineering, The Szewalski Institute of Fluid Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-952 Gdańsk, Poland
² Department of Marine Electronics, Gdynia Maritime University, Morska 81–87, 81-225 Gdynia, Poland
³ Department of Electrical and Electronic Engineering, Oita University, Oita 870-1192, Japan
⁴ Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aboba, Sendai 980-8577, Japan

^a e-mail: kocik@imp.gda.pl

Received: 30 September 2012
Revised: 9 January 2013
Accepted: 9 August 2013
Published online: 3 October 2013

Abstract

In this paper, Schlieren photography technique has been applied for the visualization of the pressure field of a single-shot underwater pulsed discharge. A needle-to-plane electrode configuration submerged in distilled water was used. The detailed time- and space-resolved images of both streamers and pressure waves were captured. As a result, several phenomena, such as the phase change prior to the initiation of the discharge, primary and secondary streamers propagation, shock wave generation, and the bubble formation, were observed. From these observations, a scenario of multiple events from prebreakdown to post-discharge was proposed. The gas bubbles generated in discharge were used to visualize the electrohydrodynamic flow induced by the discharge.