Underwater shock wave induced by pulsed discharge on water

2021 ◽  
Author(s):  
Tomohiro Furusato ◽  
Mitsuru Sasaki ◽  
Yoshinobu Matsuda ◽  
Takahiko Yamashita
Keyword(s):  
Biological Sciences ◽  
Shock Wave ◽  
Shock Waves ◽  
Surface Discharge ◽  
Underwater Shock Wave ◽  
Mean Velocity ◽  
Combined Action ◽  
Underwater Shock ◽  
The Mean ◽  
Wave Induced

Abstract Plasmas on liquids have provided significant applications in material, environmental, and biological sciences. The mechanisms of these chemical reactions in liquids have been primarily discussed by the plasma–liquid interactions and convection by an electrohydrodynamic flow. Although shock waves play a significant role in the radical formation, agitation, and cell destruction, not much information is available on underwater shock waves induced by the surface discharge on water. In this study, an underwater shock wave generated by the pulsed surface discharge on water using the laser shadowgraph method has been demonstrated. The results reveal that the shock wave generated by the discharge on water was transmitted into the water. The mean velocity of the shock wave reached 1.7 km/s. The results indicate that the surface discharge accelerates the reaction in the water by the combined action of the underwater shock wave and the plasma reaction at the air–water interface. The results are expected to aid in the understanding the mechanisms of existing applications, such as decomposition, synthesis, and sterilization.

scholarly journals Study of Ho:YAG Laser Generated Underwater Shock Waves and Cavity Bubble for Revascularization Therapy

2000 ◽  
Author(s):  
S. H. R. Hosseini ◽  
T. Hirano ◽  
O. Onodera ◽  
K. Takayama
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Early Stage ◽  
Underwater Shock Wave ◽  
Ho:Yag Laser ◽  
Direct Laser ◽  
Order Of Magnitude ◽  
Underwater Shock

Abstract For applying shock waves to precise medical procedures like neurosurgery, a reliable generation of micro shock waves is required. Such sensitive applications make limits on usage of conventional underwater shock wave sources like Extracoporeal Shock Waves ESW [1] or micro explosives [2]. In the present study a Q-switched Ho:YAG laser and an optical fiber are used. Advantages of this method over previous shock wave sources are two order of magnitude reduction in focusing area if compared with ESW and elimination of product gases of micro explosives. Nakahara and Nagayama [3] studied underwater shock waves emanated from surface of an optical fiber by pulse Nd:YAG laser input using shadowgraph technique. Their qualitative study limited to visualization of shock waves at its early stage. The present research aims to clarify quantitatively process of the shock wave generation by direct laser beam irradiation through optical fibers, growth and behavior of generated cavities, and structure of heat induced flow in front of the optical fiber.

On Generation of Ultra-High Pressure by Converging of Underwater Shock Waves

1998 ◽  
Vol 120 (1) ◽  
pp. 51-55 ◽  
Author(s):  
S. Itoh ◽  
S. Kubota ◽  
S. Nagano ◽  
M. Fujita
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Detonation Wave ◽  
Simulation Method ◽  
Ceramic Materials ◽  
Underwater Shock Wave ◽  
Water Chamber ◽  
Metallic Compounds ◽  
Underwater Shock ◽  
Graph System

The characteristics of a new assembly for the shock consolidation of difficult-to-consolidate powders, such as inter-metallic compounds or ceramic materials, were investigated by both the experimental method and numerical simulation method. The assembly consists of an explosive container, a water chamber, and a powder container. Once the explosive is detonated, a detonation wave occurs and propagates, and then impinges on the water surface of the water chamber. After that, there occurs immediately an underwater shock wave in the water chamber. The underwater shock wave interacts with the wall of the chamber during its propagation so that its strength is increased by the converging effect. We used the usual shadow graph system to photograph the interaction process between detonation wave and water. We also used a Manganin piezoresistance gage to measure the converged pressure of the conical water chamber. Finally, we numerically investigated, in detail, the converging effects of the various conical water chambers on the underwater shock waves. The experimental results and the correspondingly numerical results agree quite well with each other.

An Investigation on the Properties of Underwater Shock Waves Generated in Underwater Explosions of High Explosives

1997 ◽  
Vol 119 (4) ◽  
pp. 498-502 ◽  
Author(s):  
S. Itoh ◽  
Z. Liu ◽  
Y. Nadamitsu
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Numerical Simulations ◽  
Underwater Explosion ◽  
High Explosives ◽  
Underwater Shock Wave ◽  
Underwater Explosions ◽  
Expansion Test ◽  
Gas Products ◽  
Underwater Shock

A cylinder expansion test for high explosives was carried out to determine JWL parameters. Using the JWL parameters, we carried out numerical simulations of the underwater shock waves generated by the underwater explosion of the high explosives. Our results showed that the behavior of the underwater shock waves at the vicinity of the explosives differs greatly from that far from the explosives. Especially, the strength of the underwater shock wave nearby the explosive rapidly decreases due to the effect of the expansion of the gas products.

Study of underwater shock wave induced embryonic modification in-vivo

2011 ◽  
Author(s):  
Y. Miyamoto ◽  
S.H.R. Hosseini ◽  
D.K. Kang ◽  
Y. Okuda ◽  
D. Oshita ◽  
...  
Keyword(s):  
Shock Wave ◽  
Underwater Shock Wave ◽  
Underwater Shock ◽  
Wave Induced

scholarly journals Investigation of the Propagation Characteristics of Underwater Shock Waves in Underwater Drilling Blasting

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xin Liu ◽  
Wenbin Gu ◽  
Jianqing Liu ◽  
Zhenxiong Wang ◽  
Jinglin Xu ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Linear Regression Analysis ◽  
Time History ◽  
Engineering Practice ◽  
Underwater Shock Wave ◽  
Pressure Time ◽  
Underwater Shock ◽  
Measured Pressure ◽  
Fitting Model

During the first-stage project of the main channel of Ningbo-Zhoushan Port’s Shipu Harbor, underwater shock waves were monitored. By analyzing a typical measured pressure time history curve, the characteristics of underwater shock waves in an engineering context were obtained. We obtained a traditional exponential attenuation formula for underwater shock waves based on the measured data, simplified the model of underwater drilling blasting based on engineering practice, deduced a revised formula for underwater shock wave peak overpressure on the basis of dimensional analysis, established a linear fitting model, and obtained the undetermined coefficients of the revised formula using a linear regression analysis. In addition, the accuracies of the two formulas used to predict underwater shock wave peak overpressure and the significance order of influence and influence mechanism of factors included in the revised formula on the underwater shock wave peak overpressure were discussed.

scholarly journals On pressure impulse of a laser-induced underwater shock wave

2016 ◽  
Vol 808 ◽  
pp. 5-18 ◽  
Author(s):  
Yoshiyuki Tagawa ◽  
Shota Yamamoto ◽  
Keisuke Hayasaka ◽  
Masaharu Kameda
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Underwater Shock Wave ◽  
Pressure Impulse ◽  
Time Integral ◽  
Wide Range ◽  
Experimental Parameters ◽  
Pressure Peak ◽  
Underwater Shock ◽  
Spherical Shock

We experimentally examine a laser-induced underwater shock wave paying special attention to the pressure impulse, the time integral of the pressure evolution. Plasma formation, shock-wave expansion and the pressure in water are observed simultaneously using a combined measurement system that obtains high-resolution nanosecond-order image sequences. These detailed measurements reveal a distribution of the pressure peak which is not spherically symmetric. In contrast, remarkably, the pressure impulse is found to be symmetrically distributed for a wide range of experimental parameters, even when the shock waves are emitted from an elongated region. The structure is determined to be a collection of multiple spherical shock waves originating from point-like plasmas in the elongated region.

scholarly journals Experimental Study on Peak Pressure of Shock Waves in Quasi-Shallow Water

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Zhenxiong Wang ◽  
Wenbin Gu ◽  
Jianqing Liu
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Peak Pressure ◽  
Small Scale ◽  
Underwater Shock Wave ◽  
Underwater Explosions ◽  
Underwater Shock ◽  
Similarity Law ◽  
Similarity Laws ◽  
Water Depths

Based on the similarity laws of the explosion, this research develops similarity requirements of the small-scale experiments of underwater explosions and establishes a regression model for peak pressure of underwater shock waves under experimental condition. Small-scale experiments are carried out with two types of media at the bottom of the water and for different water depths. The peak pressure of underwater shock waves at different measuring points is acquired. A formula consistent with the similarity law of explosions is obtained and an analysis of the regression precision of the formula confirms its accuracy. Significance experiment indicates that the influence of distance between measuring points and charge on peak pressure of underwater shock wave is the greatest and that of water depth is the least within the range of geometric parameters. An analysis of data from experiments with different media at the bottom of the water reveals an influence on the peak pressure, as the peak pressure of a shock wave in a body of water with a bottom soft mud and rocks is about 1.33 times that of the case where the bottom material is only soft mud.

Explosive Welding Using Underwater Shock Wave Generated by the Detonation of the Detonating Code

2011 ◽  
Vol 673 ◽  
pp. 265-270 ◽  
Author(s):  
Akihisa Mori ◽  
Li Qun Ruan ◽  
Kazumasa Shiramoto ◽  
Masahiro Fujita
Keyword(s):  
Shock Wave ◽  
Sound Velocity ◽  
Detonation Velocity ◽  
Explosive Welding ◽  
New Method ◽  
Underwater Shock Wave ◽  
Metal Plates ◽  
Experimental Parameters ◽  
Underwater Shock ◽  
Point Velocity

Detonating code is a flexible code with an explosive core. It is used to transmit the ignition of explosives with high detonation velocity in the range of 5.5 to 7 km/s. However, it is difficult to use detonating code for the explosive welding of common metals since the horizontal point velocity usually exceeds the sound velocity. Hence, in the present work, a new method using underwater shock wave generated by the detonation of detonating code was tried. The details of the experimental parameters and the results are presented. From the results it is observed that the above technique is suitable to weld thin metal plates with relatively less explosives.

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