A generation of focused shock waves by underwater multichannel pulsed electrical discharge on a porous-ceramic-coated electrode in saline water is studied. This work describes the effect solution conductivity pressure waves. It was found that amplitude has nonlinear dependence conductivity: The increases with increase up to 18-20 mS/cm and then decreases again. In this paper, we show two effects take place. First, energy dissipated depends impedance system being affected conductivity....

A generator of two successive shock waves focused on a common focal point has been developed. Cylindrical pressure created by multichannel electrical discharges cylindrical composite anodes are metallic parabolic reflector-cathode. Near the focus, transformed into strong waves. The energized from separate power supplies. This allows us to vary time interval between and stagger waves' arrival point. Schlieren photographs region show that mutual interaction results in generation large number...

The results of experimental research on the acoustic and electrical characteristics underwater spark discharges facilitated by a preliminary discharge are presented. latter was produced through application short duration high-voltage pulse formed Marx generator. this lead to formation low-density region in form streamer which transformed an oscillating vapor cavity. It shown that method provided breakdown significantly increased interelectrode gap for same charging voltage main capacitor...

This paper describes the time evolution of ball plasmoids generated by millisecond atmospheric discharge in contact with water. The aim this was to clarify an initiation and a formation mechanism plasmoid. use higher frame rate filming shorter exposition time, comparison past experiments, allows us observe fast processes that occur during plasmoid evolution. We assert initial electrical breakdown cathode ceramic tube filled conductive liquid is essential for further formation. It generates...

The prime objective of this article is to determine the accuracy prediction underwater spark expansion using an incompressible approach. A channel studied experimentally a high-speed camera and optical hydrophone. experimental results are compared with solutions three sets mathematical equations for liquids. detailed comparison between these numerical simulations shows existence strict limit applicability approximation. However, within limit, description approach provides reasonable...

Gas discharge plasma generated above the surface of conductive aqueous solutions in a glass capillary was used to study penetration from bubble (imitated by space meniscus liquid capillary) into bulk liquid. The experiments were conducted at both polarities with high-voltage needle electrode placed surface. Different examined (distilled water, saline solutions). High-speed shadowgraphy as main diagnostic tool for disturbances plasma-liquid interface. It has been found that electric field...

In this paper, a new method of generation an electrical discharge in water using plate electrodes is proposed. The plate-to-plate configuration cannot be easily generated because low uniform field. A nitrogen bubble injected into one the to create favorable condition for breakdown. studied high-speed framing camera. Two interesting effects have been observed. First, preferentially initiated on cathode. Second, positive streamer reveals nontypical morphology. physical mechanisms initiation...

Time-resolved observation of an electrical discharge in water using high-speed camera is presented. The generated a pin to geometry with shock wave assistance. generates cavitation bubbles that enhance the discharge. initiation and growth streamers are observed. An electric spark as result one streamer reaching counter electrode.

Plate-to-plate geometry is not usually used for a discharge generation in water because of low electric field that insufficient electrical breakdown between electrodes. In the present research, new method using plate electrodes proposed. A high voltage pulse applied to pair disc at time when shock wave passing them. This allows depositing higher energy than with case pin-to-pin (or pin-to-plate electrodes) without their destruction. initiation occurs numerous cavitation bubbles generated by...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation V. Stelmashuk; Observation of a spark channel generated in water with shock wave assistance plate-to-plate electrode configuration. Physics Plasmas 1 January 2014; 21 (1): 010703. https://doi.org/10.1063/1.4861877 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote...

This paper is aimed at the investigation of acoustic and spectral characteristics underwater electric sparks generated between two plate electrodes, using synchronized gas bubble injection. There are purposes served by discharge initiation in bubble. Firstly, it creates a favorable condition for electrical breakdown. Secondly, provides an opportunity direct spectroscopy plasma light emission, avoiding water absorption. The effect absorption on captured spectra was studied. It observed that...

Commercial passenger aircraft are on average struck by lightning once a year. The in-flight strike damage assessment system (ILDAS) project is to develop and validate prototype of capable measurement the current waveform reconstruction path current. This paper discusses various magnetic sensors, their rationale some tests. Inductive sensors require an integrator in signal conditioning. Much attention has been paid passive integrator, which first stage preliminarily responsible for EMC.

An experimental investigation has been conducted to study the morphology of electrical discharge performed in a plate-to-plate configuration. breakdown configuration is generally difficult produce because weak uniform electric field interelectrode region. The generated when shock wave used. It generates number cavitation bubbles, which serve as locations for streamers growth. Time-resolved observation using high-speed camera presented.

Lightning strikes a commercial airliner on the average once year. The European project ldquoIn-flight Strike Damage Assessment System (ILDAS)rdquo [1] aims to develop and validate prototype of system capable 1) reconstruct current intensity wave form, 2) determine region impact aircraft, 3) build maintenance database. Suitable sensors rely determination magnetic field during strike. Probes considered are inductive coils solid state sensors, combined in such way that these cover full dynamic...

Gas dynamic modeling approach was applied to "plasmoid" formed in experimental electrical discharge breakdown a cathode ceramic tube filled by conductive liquid. Measured parameters were the model order improve it. Qualitative agreement observed between behavior of and results. Temperature distribution results also agree with experiment which temperature 2000 K registered.

Abstract The pressure in an underwater discharge channel is the main parameter that influences all its applications. In this study, we investigate a relatively large gap with plane-to-plane electrode geometry uses assistance of injected gas bubble for breakdown. delay application high voltage following injection from grounded determines initial dimensions bubble. We examined three types discharge: (a) easy triggering, (b) medium bubble, and (c) small difficult triggering. diagnostic tool H α...

Abstract In this study, a new finite-difference cylindrical model of long underwater spark is developed that allows us to numerically calculate the time evolution channel from given power input. A one dimensional simulation starts in breakdown moment. The whole development divided into steps equal duration. investigated region consists homogeneous central column filled with weakly ionized vapour and its atomic fragments, co-axial liquid slabs thickness beginning. each step, some energy...