Artykuły w czasopismach: „Underwater explosions”

1

Yu, Jun, Hai-tao Li, Zhen-xin Sheng, Yi Hao i Jian-hu Liu. "Numerical research on the cavitation effect induced by underwater multi-point explosion near free surface". AIP Advances 13, nr 1 (1.01.2023): 015021. http://dx.doi.org/10.1063/5.0136546.

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In this study, the cavitation effect induced by two charges in underwater explosions near free surfaces is numerical researched by two dimensional compressible multiphase fluids based on a four-equation system with a phase transition model. The occurrence of the generation, development, and collapse of cavitation in two-charge underwater explosions near free surfaces can be captured directly. The detailed density, pressure, and vapor volume fraction contours during the interaction process are obtained and can better reveal the characteristic underlying the cavitation, free surface, and explosion bubbles. Numerical results reveal that the cavitation domain has expanded to an area much deeper than the explosion bubble location in two-charge underwater explosions, which should be paid enough attention due to its influence on the input load of underwater structures. The detailed density and pressure contours during the interaction process can also be captured and can better reveal the mechanism underlying the explosion bubble, cavitation, and surface wave dynamics. The present results can expand the currently limited database of multiphase fluid in underwater explosions and also provide new insights into the strong nonlinear interaction between underwater explosion and cavitation, which provides a deep understanding of multi-point explosions.

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Zhang, Zhifan, Hailong Li, Longkan Wang, Guiyong Zhang i Zhi Zong. "Formation of Shaped Charge Projectile in Air and Water". Materials 15, nr 21 (7.11.2022): 7848. http://dx.doi.org/10.3390/ma15217848.

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With the improvement of the antiknock performance of warships, shaped charge warheads have been focused on and widely used to design underwater weapons. In order to cause efficient damage to warships, it is of great significance to study the formation of shaped charge projectiles in air and water. This paper uses Euler governing equations to establish numerical models of shaped charges subjected to air and underwater explosions. The formation and the movement of Explosively Formed Projectiles (EFPs) in different media for three cases: air explosion and underwater explosions with and without air cavities are discussed. First, the velocity distributions of EFPs in the formation process are discussed. Then, the empirical coefficient of the maximum head velocity of EFPs in air is obtained by simulations of air explosions of shaped charges with different types of explosives. The obtained results agree well with the practical solution, which validates the numerical model. Further, this empirical coefficient in water is deduced. After that, the evolutions of the head velocity of EFPs in different media for the above three cases are further compared and analyzed. The fitting formulas of velocity attenuation of EFPs, which form and move in different media, are gained. The obtained results can provide a theoretical basis and numerical support for the design of underwater weapons.

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Miralles, Ramón, Guillermo Lara, Alicia Carrión i Manuel Bou-Cabo. "Assessment of Arrow-of-Time Metrics for the Characterization of Underwater Explosions". Sensors 21, nr 17 (4.09.2021): 5952. http://dx.doi.org/10.3390/s21175952.

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Anthropogenic impulsive sound sources with high intensity are a threat to marine life and it is crucial to keep them under control to preserve the biodiversity of marine ecosystems. Underwater explosions are one of the representatives of these impulsive sound sources, and existing detection techniques are generally based on monitoring the pressure level as well as some frequency-related features. In this paper, we propose a complementary approach to the underwater explosion detection problem through assessing the arrow of time. The arrow of time of the pressure waves coming from underwater explosions conveys information about the complex characteristics of the nonlinear physical processes taking place as a consequence of the explosion to some extent. We present a thorough review of the characterization of arrows of time in time-series, and then provide specific details regarding their applications in passive acoustic monitoring. Visibility graph-based metrics, specifically the direct horizontal visibility graph of the instantaneous phase, have the best performance when assessing the arrow of time in real explosions compared to similar acoustic events of different kinds. The proposed technique has been validated in both simulations and real underwater explosions.

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Kiciński, Radosław, i Bogdan Szturomski. "Pressure Wave Caused by Trinitrotoluene (TNT) Underwater Explosion—Short Review". Applied Sciences 10, nr 10 (15.05.2020): 3433. http://dx.doi.org/10.3390/app10103433.

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The development of computational techniques and computer hardware has an impact the analysis of short-term (fast-changing) processes, such as the impact of a non-contact underwater explosion pressure waves. A theory of underwater explosions, gas bubble formation and pressure waves are presented. The course of the pressure wave in time, and its propagation in the acoustic medium are presented. The study presents empirical descriptions of non-contact pressure explosion waves. We propose to use them in simulations of ship hull strength and other objects immersed in liquids that are exposed to the effects of non-contact trinitrotoluene (TNT)-charge explosions. Pressure distributions and their time courses given by authors such as R.H. Cole, J.S. Nawagin, W. Stiepanow, T.E. Farley and H.G. Snay, T.L. Geers and K.S. Hunter are compared. A method of pressure wave modeling using acoustic media implemented in Computer Aided Engineering (CAE) programs is presented. The results of the values and the time course of the pressure acting on the underwater object are given. The influence of FEM (Finite Element Method) mesh density on the obtained results is examined and presented. The aim of the article is to expand our knowledge of underwater explosions, compare mathematical descriptions of the pressure waves developed by different authors and show the differences between them. In addition, we present the distinction between contact and non-contact explosions and analyze how changes in the mesh density of acoustic elements affects the reflection of the incident wave caused by an underwater explosion.

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Wang, Yan, Xiaoming Wang, Zhehan Liu, Wei Tang, Jian Li, De Nan i Shiya Zou. "Estimation on the Underwater Explosion Equivalent Based on the Threshold Monitoring Technique". Shock and Vibration 2021 (18.10.2021): 1–8. http://dx.doi.org/10.1155/2021/1933744.

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Underwater nuclear explosions can be monitored in near real-time by the hydroacoustic network of the International Monitoring System (IMS) established by the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which could also be used to monitor underground and atmospheric nuclear explosions. The equivalent is an important parameter for the nuclear explosions’ monitoring. The traditional equivalent estimation method is to calculate the bubble pulsation period, which is difficult to obtain satisfactory results under the current conditions. In this paper, based on the passive sonar equation and the conversion process of acoustic energy parameters in the hydroacoustic station, the threshold monitoring technique used for underwater explosion equivalent estimation was studied, which was not limited to the measurement conditions and calculation results of the bubble pulsation period. Through the analysis of practical monitoring data, estimation on the underwater explosion equivalent based on the threshold monitoring technique was verified to be able to reach the accuracy upper boundary of current methods and expand the measurement range to further ocean space, along with the real-time monitoring capability of IMS hydroacoustic stations which could be estimated by this method.

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6

Itoh, S., Z. Liu i Y. Nadamitsu. "An Investigation on the Properties of Underwater Shock Waves Generated in Underwater Explosions of High Explosives". Journal of Pressure Vessel Technology 119, nr 4 (1.11.1997): 498–502. http://dx.doi.org/10.1115/1.2842336.

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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.

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7

Chen, Wenge, Lele Cheng, Chao Yu, Haijun Wu, Fenglei Hang i Ziqi Wu. "Experimental Study on the Cumulative Damage of Shipboard Structure Subject to Near-field Underwater Explosions". Journal of Physics: Conference Series 2419, nr 1 (1.01.2023): 012003. http://dx.doi.org/10.1088/1742-6596/2419/1/012003.

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Abstract To explore the cumulative damage law of near-field underwater explosions on the side of the ship structure, the multi-cabin model of the shipboard local structure is designed and applied to close-in underwater explosion experiments with different explosive masses and model conditions. The pressure load of the explosion shock wave near the water surface is obtained and analyzed. The damage results, such as the damage pattern of the model and the damage range of cabins, are acquired. The comprehensive comparison shows that: the secondary explosion on the side has a significant cumulative damage effect; the damage pattern of the structure is closely related to the proportional distance of the explosion. The damaged power of a single large charge explosion on the shipboard is bigger than the cumulative damage caused by two small explosions. The results of this study can provide a reference for the research on the damage and protection of the ship.

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Yu, Jun, Xianpi Zhang, Yanjie Zhao, Lunping Zhang, Jiping Chen i Yuanqing Xu. "Study on the Influence of a Rigid Wall on Cavitation in Underwater Explosions Near the Free Surface". Applied Sciences 14, nr 5 (23.02.2024): 1822. http://dx.doi.org/10.3390/app14051822.

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A two-fluid, phase transition-based multiphase flow model is employed to simulate the dynamics of phase transition between liquid and vapor phases during shock wave and rarefaction wave propagation in underwater explosions. The aim is to understand the influence of a rigid wall on the cavitation evolution process and the cavitation collapse load, considering various charge quantities and water depths. The evolution of crucial physical qualities, such as the density, pressure, and the cavitation domain, within the flow field are analyzed and summarized. The presence of a rigid wall is found to significantly impact the cavitation evolution process in underwater explosions. It affects the shape, size, and dynamics of the cavitation domain, as well as the interaction between the explosion and the surrounding fluid. Specifically, the reflected wave on the wall influences the cavitation collapse load, leading to notable differences in the collapse time and collapse pressure compared to free-field conditions. Under different operating conditions, the size and position of the cavitation domain exhibit distinct changes. The proximity of the rigid wall results in unique patterns of cavitation domain evolution, which in turn lead to variations in the pressure distribution and the emergence of new cavitation regions. The findings of this study provide valuable insights into the behavior of cavitation and atomization induced by underwater explosions near the free surface. The understanding gained from these investigations can contribute to the development of effective safety measures and protective strategies in marine and underwater engineering applications. By accurately predicting and mitigating the effects of cavitation, it is possible to enhance the design and operation of underwater structures, ensuring their integrity and minimizing the potential risks associated with underwater explosions.

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9

Yan, Qiushi, Chen Liu, Jun Wu, Jun Wu i Tieshuan Zhuang. "Experimental and Numerical Investigation of Reinforced Concrete Pile Subjected to Near-Field Non-Contact Underwater Explosion". International Journal of Structural Stability and Dynamics 20, nr 06 (30.05.2020): 2040003. http://dx.doi.org/10.1142/s0219455420400039.

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High-pile wharf is an important port structure and may suffer from accidental explosions or terrorist bombing attack during the service life. The reinforced concrete (RC) pile is one of the popular vertical load-bearing piles of high-pile wharf structure. As a main load-bearing member of the high-pile wharf structure, the damage of RC pile due to underwater explosive may cause subsequently progressive collapse of the whole structure. In this paper, the dynamic response and failure mode of RC pile in high-pile wharf structure under the near-field non-contact underwater explosion are investigated using a combined experimental and numerical study. First, a typical RC pile was designed and tested for the near-field non-contact underwater explosion. The failure mode and damage of the RC pile specimen were obtained and analyzed. Second, the numerical model of the RC pile under near-field non-contact underwater explosion was established by adopting the commercial software AUTODYN, and then validated based on experimental results. It was shown that the results from numerical model and experimental test compared very well in terms of the damage pattern and lateral displacement. Furthermore, the full-scale numerical model of the RC pile for the near-field non-contact underwater explosion was developed based on the validated numerical model to investigate the damage pattern and failure mode of RC pile under varied underwater explosives. Lastly, the safety distance for the RC pile for the underwater explosion loading with consideration of different explosive mass, the explosive depth and the concrete strength was suggested. The outcome of this study presented reference for analysis, assessment and design of the type of RC pile for high-pile wharf structure subjected to near-field non-contact underwater explosion.

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Su, Hao-Chen, Jun Wang, Yun-Long Liu i Yong-Qiang Gao. "Experimental Study on the Underwater Explosion Bubble Near deformable boundary". Journal of Physics: Conference Series 2660, nr 1 (1.12.2023): 012012. http://dx.doi.org/10.1088/1742-6596/2660/1/012012.

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Abstract Studying near-field underwater explosions is important for the research of submersible and underwater explosive weapons. In this study, we conducted experiments to investigate the coupling of near-field underwater explosion bubbles with titanium alloy plates and steel plates. Our findings show that the boundary of a titanium alloy plate causes the first pulsation period of a bubble to be longer than in the free field, while the boundary of a steel plate causes the first pulsation period of a bubble to be shorter than in the free field. Furthermore, we simulated the process of the explosion and found that changes in the period may be caused by ventilation.

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Gel'fand, B. E., i K. Takayama. "Similarity Criteria for Underwater Explosions". Combustion, Explosion, and Shock Waves 40, nr 2 (marzec 2004): 214–18. http://dx.doi.org/10.1023/b:cesw.0000020144.55275.df.

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Molyneaux, T. C. K., Long-Yuan Li i N. Firth. "Numerical simulation of underwater explosions". Computers & Fluids 23, nr 7 (wrzesień 1994): 903–11. http://dx.doi.org/10.1016/0045-7930(94)90060-4.

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13

Dall'Osto, David R. "The Sound from Underwater Explosions". Acoustics Today 19, nr 1 (2023): 12. http://dx.doi.org/10.1121/at.2023.19.1.12.

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14

Seger, Kerri D., Shyam Madhusudhana, Holger Klinck, Kevin D. Heaney i John Boyle. "Using before-after control-impact methodology to quantify effects of full ship shock trial explosions on marine fauna". Journal of the Acoustical Society of America 155, nr 3_Supplement (1.03.2024): A133. http://dx.doi.org/10.1121/10.0027061.

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In the summer of 2021, the US Navy conducted a Full Ship Shock Trial (FSST) for the USS Gerald R. Ford. This involved three large underwater explosions off the coast of Florida, USA. We collected underwater acoustic recordings, using low-sensitivity recorders, for the Naval Undersea Warfare Center to validate their underwater acoustic propagation models. We also deployed SoundTraps on the shallow moorings to collect additional acoustical biologics data in hopes of measuring any acoustic responses of marine fauna to the explosions. The acoustic energy of the explosions did not propagate up the continental slope and were hence not captured by the SoundTraps on the shallow moorings. However, our analyses did yield some notable changes in acoustic behavior after as compared to before the explosions. Here, we describe how our field plan was designed for before-after control-impact (BACI) hypothesis testing and discuss our analyses and findings of the few significant cases. These results lend insight for improving the impact assessments and conducting behavioral response studies during a future FSST or other large underwater explosions.

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15

Dulnev, A. I. "Underwater explosion in open water: gas bubble parameters". Transactions of the Krylov State Research Centre 1, nr 403 (15.02.2023): 31–47. http://dx.doi.org/10.24937/2542-2324-2023-1-403-31-47.

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Object and purpose of research. This paper discusses underwater explosion. The purpose of the study was to justify the mathematical model enabling the assessment of gas bubble pulses of underwater explosion for a wide range of explosion depths and charge weights. Subject matter and methods. The paper discusses an explosion in open-water conditions. The study relies on analytical materials, numerical solution of common differential equations and on the experimental data. Main results. The study describes calculation expressions for gas bubble pulse parameters available in literature. It also compares calculation results with the experimental data for TNT explosions. Conclusion. As compared to existing solutions and empirical expressions, the mathematical model suggested in this paper enables the assessment of pulse parameters for a wide range of explosion depths and charge weights. Calculation results obtained as per this model correlate with available test data. The results of this work may be used to estimate underwater explosion impact upon marine objects and structures.

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Mair, Hans U. "Review: Hydrocodes for Structural Response to Underwater Explosions". Shock and Vibration 6, nr 2 (1999): 81–96. http://dx.doi.org/10.1155/1999/587105.

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The applicability of the various hydrocode methodologies (Lagrangian, Eulerian, Coupled Eulerian–Lagrangian, and Arbitrary Lagrangian–Eulerian) for structural response to underwater explosions is reviewed. Only codes employing “structural elements” are realistically applicable to the analysis of thin-walled structural response to underwater explosions.

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Wang, Zhenxiong, Wenbin Gu i Jianqing Liu. "Experimental Study on Peak Pressure of Shock Waves in Quasi-Shallow Water". Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/702178.

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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.

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Hayward, Matthew W., Colin N. Whittaker, Emily M. Lane, William L. Power, Stéphane Popinet i James D. L. White. "Multilayer modelling of waves generated by explosive subaqueous volcanism". Natural Hazards and Earth System Sciences 22, nr 2 (25.02.2022): 617–37. http://dx.doi.org/10.5194/nhess-22-617-2022.

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Abstract. Theoretical source models of underwater explosions are often applied in studying tsunami hazards associated with subaqueous volcanism; however, their use in numerical codes based on the shallow water equations can neglect the significant dispersion of the generated wavefield. A non-hydrostatic multilayer method is validated against a laboratory-scale experiment of wave generation from instantaneous disturbances and at field-scale subaqueous explosions at Mono Lake, California, utilising the relevant theoretical models. The numerical method accurately reproduces the range of observed wave characteristics for positive disturbances and suggests a relationship of extended initial troughs for negative disturbances at low-dispersivity and high-non-linearity parameters. Satisfactory amplitudes and phase velocities within the initial wave group are found using underwater explosion models at Mono Lake. The scheme is then applied to modelling tsunamis generated by volcanic explosions at Lake Taupō, New Zealand, for a magnitude representing an ejecta volume of 0.1 km3. Waves reach all shores within 15 min with maximum incident crest amplitudes around 0.2 m at shores near the source. This work shows that the multilayer scheme used is computationally efficient and able to capture a wide range of wave characteristics, including dispersive effects, which is necessary when investigating subaqueous explosions. This research therefore provides the foundation for future studies involving a rigorous probabilistic hazard assessment to quantify the risks and relative significance of this tsunami source mechanism.

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So Gu, Kim. "Forensic seismology vis-à-vis an underwater explosion for the Roks Cheonan sinking in the Yellow Sea of the Korean Peninsula". International Journal of Physics Research and Applications 6, nr 1 (18.04.2023): 073–89. http://dx.doi.org/10.29328/journal.ijpra.1001054.

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Most underwater explosions show characteristics of a bubble pulse and reverberation effects. To specifically identify the cause of an underwater explosion, it is most important to find a bubble pulse and reverberation effects using spectral and cepstral analyses. For a very shallow underwater explosion, spectral analysis is preferable to cepstral analysis. Time-domain analyses show bubble pulses as well as positive polarities of the first P-wave arrivals on the vertical component, and frequency-domain spectral analyses also clearly reveal the bubble pulse and reverberation effects. This study includes comparative studies including a Russian underwater nuclear explosion and US Navy shock trials. The ROKS Cheonan sinking was a shallow underwater explosion that occurred near the surface showing a bubble jet characteristic resulting in splitting the ship into two pieces including a bubble pulse and reverberation effects. The findings of a bubble jet and a toroidal bubble deformation including a bubble pulse are highlighted for a shallow underwater explosion in this study. The ROKS Cheonan sinking took place off the Baengnyeong Island in the Yellow Sea of the Korean Peninsula at a depth of about 8 m in the sea depth of 44 m on March 26, 2010. The explosive charge weight was estimated at 136 kg TNT which is equivalent to one of the abandoned land control mines (LCM) that were deployed near the Northern Limited Lines (NLL) in the Yellow Sea in the late 1970s.

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Sheng, Zhen-xin, Rong-zhong Liu i Rui Guo. "Reverberation generated by sequential underwater explosions". Acoustical Physics 58, nr 2 (marzec 2012): 236–42. http://dx.doi.org/10.1134/s1063771012020200.

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Baumann-Pickering, Simone, Amanda J. Debich, Ana Širović, James V. Carretta, Jennifer S. Trickey, Rohen Gresalfi, Marie A. Roch, Sean M. Wiggins i John A. Hildebrand. "Impact of underwater explosions on cetaceans". Journal of the Acoustical Society of America 134, nr 5 (listopad 2013): 4045. http://dx.doi.org/10.1121/1.4830763.

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Zhao, Qian, Jianxin Nie, Qiushi Wang, Zhengqing Zhou i Qingjie Jiao. "Numerical and experimental study on cyclotrimethylenetrinitramine/aluminum explosives in underwater explosions". Advances in Mechanical Engineering 8, nr 10 (październik 2016): 168781401666790. http://dx.doi.org/10.1177/1687814016667905.

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Librescu, Liviu, Sang-Yong Oh i Jorg Hohe. "Implication of Nonclassical Effects on Dynamic Response of Sandwich Structures Exposed to Underwater and In-Air Explosions". Journal of Ship Research 51, nr 02 (1.06.2007): 83–93. http://dx.doi.org/10.5957/jsr.2007.51.2.83.

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A study devoted to the dynamic response of sandwich panels to underwater and in-air explosions is presented. The study is carried out in the context of a geometrically nonlinear model of sandwich structures featuring anisotropic laminated face sheets and a transversely compressible orthotropic core. The unsteady pressure generated by the explosion and acting on the face of the sandwich panel includes the effect of the pressure wave transmission through the core. Its implications on the structural time-histories as corresponding to the underwater and in-air explosions are put into evidence. The effects of the transverse core compressibility on dynamic response are highlighted. In this sense, one of its major implications is the possibility to capture interactively the global and local (wrinkling) dynamic response of the panel. It is shown that implementation of the structural tailoring technique in the face sheets can constitute an important mechanism for enhancing the dynamic load-carrying capacity of sandwich panels when exposed to blast pulses. Effects of the core, the composite architecture of face sheets, orthotropy of the material of the core, geometrical non-linearities, initial geometric imperfection, and the damping ratio are investigated, and their implications for the dynamic response are highlighted. The comprehensive structural model considered in conjunction with the time-dependent loads generated by the underwater and in-air explosions, and the results obtained in this context, are expected to contribute to a better understanding of the response behavior and to be instrumental toward a better design of these structures.

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Grządziela, Andrzej, Bogdan Szturomski i Marcin Kluczyk. "Modeling of the Minehunters Hull Strenght". Advanced Materials Research 1036 (październik 2014): 189–94. http://dx.doi.org/10.4028/www.scientific.net/amr.1036.189.

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The paper presents problems of modeling the ship’s hull subjected to the load of shock wave associated with non-contact underwater explosion. The article presents equations for describing the parameters of shock wave subjected to an impulse load. The paper presents a proposal of identification of a degree of hazard the ship’s hull forced from underwater explosion. A theoretical analysis was made of influence of changes of hull structure in vicinity of hull. Modeled signals and hull structure were recognized within sensitive symptoms of three sub models: model of hull structure, model of impact and model of propulsion system. All sub models allow testing forces and their responses in vibration spectrum using SIMULINK software and FEM models. The results of testing allowed performing simulations of a similar nature to the actual loads of underwater explosions. Virtual model of the hull of the ship responds in a similar manner to the real impacts.

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Gong, Yuxiang, Wenpeng Zhang, Zhipeng Du i Yinghao Zhu. "Numerical Study on the Sagging Damage of the Simplified Hull Girder Subjected to Underwater Explosion Bubble". Applied Sciences 13, nr 4 (10.02.2023): 2318. http://dx.doi.org/10.3390/app13042318.

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The pulsation of the bubbles resulting from underwater explosions can lead to severe damage to the structure of the ship’s hull, and even to its sinking. To study the damage mechanism of a simplified hull girder (SHG) subjected to near-field underwater explosion bubble, the Coupled Eulerian–Lagrangian (CEL) method based on verifications of the calculation accuracy was used to simulate 11 SHG structures. The sagging bend mechanism of SHGs was analyzed from the perspective of plastic hinge lines. Moreover, the length formula of the potential bend zone was studied through the assumed plastic hinge lines. The influence of transverse bulkheads on bending mode and total longitudinal strength was investigated. The results show that SHGs’ sagging damage is composed of regular plastic hinge lines, mainly depending on side plates’ folding—W-shaped in this paper. When facing the near-field underwater explosion bubble, the distant transverse bulkheads influence the total longitudinal strength and do not always play a positive role.

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Maler, D., R. Grikshtas, S. Efimov, L. Merzlikin, M. Liverts, M. Kozlov i Ya E. Krasik. "Supersonic water jets as point-like sources of extremely high pressure". Physics of Plasmas 30, nr 2 (luty 2023): 022710. http://dx.doi.org/10.1063/5.0135486.

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Two interacting supersonic water jets and collisions of a water jet with an aluminum target are studied experimentally and by hydrodynamic simulations. Supersonic water jets form, when shocks generated by underwater electrical explosions of conical wire arrays converge. The arrays are supplied by a ∼250 kA, ∼1 μs rise time current pulse. Underwater explosion of two conical arrays placed face to face produces jets propagating in air with velocities of ∼[Formula: see text] m/s leading to hot plasma formation at a temperature of ∼2200–3000 K, pressure ∼[Formula: see text] Pa, and density >[Formula: see text] m−3. When a single array explodes underwater in front of an aluminum target, the collision of the jet with the target produces a local pressure of ∼[Formula: see text] Pa on the surface of the target.

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Chen, D., L. J. Zhang, Y. Z. Lv, B. H. Li i H. P. Gu. "Sensitivity Study on Typical Parameters of Underwater Explosion Numerical Simulation". Journal of Physics: Conference Series 2478, nr 12 (1.06.2023): 122031. http://dx.doi.org/10.1088/1742-6596/2478/12/122031.

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Abstract In the numerical simulation research for underwater explosion, the selection of simulation parameters has a great influence on the results of numerical calculation. Based on the one-dimensional spherical symmetry model, this paper systematically studies the influence of three factors: grid size, water state equation and artificial viscosity coefficient on the important physical parameters of water explosion when TNT explosive is exploded in water. The important physical parameters selected for the explosion in water are the shock wave intensity, the maximu m radius of the bubble and the pulsation period of the bubble. A series of studies are carried out on underwater explosions with different grid sizes, so as to obtain the corresponding recommended grids that meet the calculation accuracy. The influence of different water state equations on the simulation results is discussed. The effect of artificial viscosity coefficient on the simulation results is analyzed. Finally, the similarity law of the model is studied to verify the universality of the model parameters.

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Doroshenko, Stanislav, Sergey Nefediev i Vadim Malykh. "DESTRUCTION OF ROCKS AND MATERIALS USING AMMUNITION BASED ON SHOCK-WAVE CUTTING TECHNOLOGY IN EMERGENCY SITUATIONS". Problems of risk management in the technosphere 2023, nr 3 (28.09.2023): 17–28. http://dx.doi.org/10.61260/1998-8990-2023-3-17-28.

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The paper assesses the effectiveness of shock-wave technology cutting for rocks and materials. A comparison of materials cutting technologies using a shock-wave and a shaped charge is done. Shows a significant reduction in the consumption of explosives and an increase in efficiency in shock-wave cutting with a simultaneous reduction in safe distances. Solving the problems of underwater explosions in the interests of rescue operations in emergency situations.

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Doroshenko, Stanislav, Sergey Nefedev i Vadim Malykh. "DESTRUCTION OF MATERIALS BY SHOCK WAVE CUTTING CHARGES UNDER WATER IN EMERGENCY SITUATIONS". Problems of risk management in the technosphere 2023, nr 4 (14.02.2024): 8–22. http://dx.doi.org/10.61260/1998-8990-2024-2023-4-8-22.

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The paper assesses the effectiveness of shock-wave technology cutting for rocks. A comparison of materials cutting technologies using a shock-wave and a shaped charge is done. Shows a significant reduction in the consumption of explosives and an increase in efficiency in shock-wave cutting with a simultaneous reduction in safe distances. Solving the problems of underwater explosions in the interests of rescue operations in emergency situations.

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30

Năstăsescu, Vasile, i Ghiță Bârsan. "Upon Bulk Cavitation Appearing in Underwater Explosions". International conference KNOWLEDGE-BASED ORGANIZATION 23, nr 3 (27.06.2017): 71–78. http://dx.doi.org/10.1515/kbo-2017-0159.

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Abstract This paper presents some results of the author’s researching in connection with SPH (smoothed particle hydrodynamics) method and underwater explosion numerical modelling. All about cavitation fundamentals are considered known and about cavitation effects upon the structures. The authors, deeply preoccupied in using of SPH method, as well in modelling of the underwater explosion effects upon structures, had to take into consideration the bulk cavitation. A main issue in this study was the knowing of the bulk cavitation domain and its characteristic parameters. Such researching was possible to be successfully carried out, only by using of the SPH method. Finally, the paper presents the relations and the working way for knowing of the bulk cavitation domain and also a numerical model using SPH method is presented. The numerical example regarding shape and dimensions of the bulk cavitation is presented together putting in evidence of some parameters which can make damages upon a structure that is in the bulk cavitation area.

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31

Rajendran, R., J. K. Paik i B. J. Kim. "Design of warship plates against underwater explosions". Ships and Offshore Structures 1, nr 4 (kwiecień 2006): 347–56. http://dx.doi.org/10.1533/saos.2005.0118.

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32

Krieger, John R., i Georges L. Chahine. "Acoustic signals of underwater explosions near surfaces". Journal of the Acoustical Society of America 118, nr 5 (listopad 2005): 2961–74. http://dx.doi.org/10.1121/1.2047147.

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33

Wiggins, Sean M., Anna Krumpel, Macey Rafter, LeRoy Dorman, John Hildebrand i Simone Baumann-Pickering. "Explosions recorded underwater offshore of southern California". Journal of the Acoustical Society of America 146, nr 4 (październik 2019): 2935. http://dx.doi.org/10.1121/1.5137193.

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34

Petri, Nadan M., Josip Dujella, Marija Definis-Gojanović, Lena Vranjković-Petri i Dražen Cuculić. "Diving-Related Fatalities Caused by Underwater Explosions". American Journal of Forensic Medicine and Pathology 22, nr 4 (grudzień 2001): 383–86. http://dx.doi.org/10.1097/00000433-200112000-00009.

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35

Shin, Young S. "Advances in ship survivability against underwater explosions". Ocean Systems Engineering 1, nr 2 (25.06.2011): 111–19. http://dx.doi.org/10.12989/ose.2011.1.2.111.

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36

Liu, Zhanke, Yin L. Young i Michael R. Motley. "Transient Response of Partially-Bonded Sandwich Plates Subject to Underwater Explosions". Shock and Vibration 17, nr 3 (2010): 233–50. http://dx.doi.org/10.1155/2010/919304.

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This paper investigated the influence of interfacial bonding on the transient response of sandwich plates subject to underwater explosions. It was found that un-bonded sandwich plates receive lower impact energy, and are able to dissipate more energy through plastic deformation of the foam core, than perfectly bonded plates. Consequently, interfacial de-bonding leads to lower net energy transfer from the explosion to the target structure although it also increases the structural deformation due to stiffness reduction. Parametric studies showed that theadvantage(diminishing of net energy transfer) is more significant than thedisadvantage(magnification of the interface deflection). Thus, interfacial de-bonding through active/passive mechanisms may be beneficial for blast-resistant designs.

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37

Wardlaw Jr., Andrew B., i J. Alan Luton. "Fluid-Structure Interaction Mechanisms for Close-In Explosions". Shock and Vibration 7, nr 5 (2000): 265–75. http://dx.doi.org/10.1155/2000/141934.

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This paper examines fluid-structure interaction for close-in internal and external underwater explosions. The resulting flow field is impacted by the interaction between the reflected explosion shock and the explosion bubble. This shock reflects off the bubble as an expansion that reduces the pressure level between the bubble and the target, inducing cavitation and its subsequent collapse that reloads the target. Computational examples of several close-in interaction cases are presented to document the occurrence of these mechanisms. By comparing deformable and rigid body simulations, it is shown that cavitation collapse can occur solely from the shock-bubble interaction without the benefit of target deformation. Addition of a deforming target lowers the flow field pressure, facilitates cavitation and cavitation collapse, as well as reducing the impulse of the initial shock loading.

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38

Wang, Jun, Jingxuan Yang, Fengfeng Wu, Tengfei Hu i Shams Al Faisal. "Analysis of fracture mechanism for surrounding rock hole based on water-filled blasting". International Journal of Coal Science & Technology 7, nr 4 (2.06.2020): 704–13. http://dx.doi.org/10.1007/s40789-020-00327-y.

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AbstractThe principles of fracture development during underwater blasting are examined based on explosion and impact dynamics, fluid dynamics, fracture dynamics, and field testing. The research reveals that the fracturing of the surrounding rock during underwater blasting is due to the combined action of shock and stress waves for the initial rock breakage and subsequent water expansion. The fracture development model for the surrounding rock of a drilling hole during underwater blasting is established. The rock fracturing range under the combined action of shock and stress waves is developed, as well as the fracture propagation rules after the wedging of the water medium into the fractures. Finally, the results of deep-hole underwater blasting tests on large rocks confirm the efficient utilization of explosive in the hole to improve the safety conditions. Accordingly, safe and static rock breaking under the detonation of high-effect explosive can be achieved. In addition, super-dynamic loading from the explosions and static loading from the water medium in the hole can be adequately combined for rock breaking.

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39

Maler, D., M. Liverts, S. Efimov, A. Virozub i Ya E. Krasik. "Addressing the critical parameters for overdamped underwater electrical explosion of wire". Physics of Plasmas 29, nr 10 (październik 2022): 102703. http://dx.doi.org/10.1063/5.0118003.

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Experimental and magnetohydrodynamic numerical simulation results and analysis of a μs- and sub- μs-timescale overdamped underwater electrical explosion of copper wires having different lengths and diameters are presented. For these explosions, ∼80% of the energy stored in the pulse generator is deposited into the wire during a time comparable or shorter than a quarter period of the underdamped discharge. It was found that the threshold values of the deposited energy density, energy density rate, and energy density per unit area, which satisfy overdamped discharge, depend on the wire parameters and on the timescale of the explosion. It was shown that the mechanism responsible for this is the process during which the wire experiences phase transitions to a low-ionized plasma, the resistivity of which is determined by the electron–neutral collision rate, which, in turn, depends on the wire radial expansion velocity, current density, and temperature.

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40

Bandari, Anashe. "Underwater electrical wire explosions can destroy steel plate". Scilight 2021, nr 24 (11.06.2021): 241107. http://dx.doi.org/10.1063/10.0005437.

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41

MacBeth, C. D., i P. W. Burton. "Surface waves generated by underwater explosions offshore Scotland". Geophysical Journal International 94, nr 2 (1.08.1988): 285–94. http://dx.doi.org/10.1111/j.1365-246x.1988.tb05902.x.

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42

Mair, Hans U. "Benchmarks for Submerged Structure Response to Underwater Explosions". Shock and Vibration 6, nr 4 (1999): 169–81. http://dx.doi.org/10.1155/1999/743708.

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Benchmarks for submerged structure response to underwater explosions (UNDEX) are compiled. Both analytical and empirical benchmarks are presented; each type has advantages and disadvantages for the purposes of model validation, though no methodology for employing these benchmarks in a model validation effort is proposed. Benchmark computations are also referenced as part of this compilation. Finally, extension of this compilation to the UNDEX response of internal equipment and floating structures, and to hydrodynamic/hydraulic ram problems, is proposed.

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43

Adushkin, A. V., V. N. Burchik, A. I. Goncharov, V. I. Kulikov, B. D. Khristoforov i V. I. Tsykanovskii. "Seismic, Hydroacoustic, and Acoustic Action of Underwater Explosions". Combustion, Explosion, and Shock Waves 40, nr 6 (listopad 2004): 707–13. http://dx.doi.org/10.1023/b:cesw.0000048276.29822.d6.

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44

Doronin, F. L. "Underwater explosions in dynamic testing of hydraulic structures". Power Technology and Engineering 52, nr 6 (marzec 2019): 657–59. http://dx.doi.org/10.1007/s10749-019-01008-w.

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45

Atanov, G. A., i S. V. Vetrov. "Calculation of contact stresses in axisymmetric underwater explosions". Journal of Soviet Mathematics 60, nr 1 (czerwiec 1992): 1328–30. http://dx.doi.org/10.1007/bf01097696.

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46

Smith, Michael E., Alyssa W. Accomando, Victoria Bowman, Brandon M. Casper, Peter H. Dahl, A. Keith Jenkins, Sarah Kotecki i Arthur N. Popper. "Physical effects of sound exposure from underwater explosions on Pacific mackerel (Scomber japonicus): Effects on the inner ear". Journal of the Acoustical Society of America 152, nr 2 (sierpień 2022): 733–44. http://dx.doi.org/10.1121/10.0012991.

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Studies of the effects of sounds from underwater explosions on fishes have not included examination of potential effects on the ear. Caged Pacific mackerel ( Scomber japonicus) located at seven distances (between approximately 35 and 800 m) from a single detonation of 4.5 kg of C4 explosives were exposed. After fish were recovered from the cages, the sensory epithelia of the saccular region of the inner ears were prepared and then examined microscopically. The number of hair cell (HC) ciliary bundles was counted at ten preselected 2500 μm2 regions. HCs were significantly reduced in fish exposed to the explosion as compared to the controls. The extent of these differences varied by saccular region, with damage greater in the rostral and caudal ends and minimal in the central region. The extent of effect also varied in animals at different distances from the explosion, with damage occurring in fish as far away as 400 m. While extrapolation to other species and other conditions (e.g., depth, explosive size, and distance) must be performed with extreme caution, the effects of explosive sounds should be considered when environmental impacts are estimated for marine projects.

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47

Zhang, Jing, Xing Hua Shi, Ding Hai Xu i Shan Wang. "Destroy Probability of Ship Defensive Structure Subjected to Underwater Contact Explosions". Advanced Materials Research 44-46 (czerwiec 2008): 297–302. http://dx.doi.org/10.4028/www.scientific.net/amr.44-46.297.

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The reliability of ship defensive structure subjected to underwater contact explosions is important both in theory and engineering. Because of the complex response of structure under explosions in which the fluid-structure-interaction should be considered, the problem under discussion could not be solved by analytical method. The Monte Carlo combined with FEM method is used to solve this problem in this paper. The samples of basic random variables that are dynamite density, the elastic modulus and ultimate strength of plate material are generated by the random number generate program. Then, with these samples, the simulations of multilayer plate-shell structure subjected to underwater contact explosions are done by LS-DYNA, and the maximum stress of each plate is obtained, which should be validated to obey the normal distribution. Based on the intensity rule, the destroy index is introduced in this paper, then the destroy probability of each plate and system are calculated using the basic theory of reliability.

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48

Walters, A. P., J. M. Didoszak i Y. W. Kwon. "Explicit Modeling of Solid Ocean Floor in Shallow Underwater Explosions". Shock and Vibration 20, nr 1 (2013): 189–97. http://dx.doi.org/10.1155/2013/901042.

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Current practices for modeling the ocean floor in underwater explosion simulations call for application of an inviscid fluid with soil properties. A method for modeling the ocean floor as a Lagrangian solid, vice an Eulerian fluid, was developed in order to determine its effects on underwater explosions in shallow water using the DYSMAS solver. The Lagrangian solid bottom model utilized transmitting boundary segments, exterior nodal forces acting as constraints, and the application of prestress to minimize any distortions into the fluid domain. For simplicity, elastic materials were used in this current effort, though multiple constitutive soil models can be applied to improve the overall accuracy of the model. Even though this method is unable to account for soil cratering effects, it does however provide the distinct advantage of modeling contoured ocean floors such as dredged channels and sloped bottoms absent in Eulerian formulations. The study conducted here showed significant differences among the initial bottom reflections for the different solid bottom contours that were modeled. The most important bottom contour effect was the distortion to the gas bubble and its associated first pulse timing. In addition to its utility in bottom modeling, implementation of the non-reflecting boundary along with realistic material models can be used to drastically reduce the size of current fluid domains.

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Zhang, Jing, i Xing Hua Shi. "Dynamic Response of Stiffened Plate under Underwater Contact Explosions". Advanced Materials Research 255-260 (maj 2011): 1665–70. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1665.

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In order to study the dynamic responses of stiffened plate under underwater contact explosions, the FEM code LS-DYNA is used to discuss the problem, six different stiffened plates are included. The stiffened plate’s distortion, the size of crevasses in the numerical simulation are analyzed. The position where the maximum plastic strain appears, the effective stress and acceleration are also described. It is revealed that the deformation of stiffened plate is different with the position of the stiffener, but the stiffener can harmonize and reduce the deformation of plate, and the whole structure will be more safety when it is subjected to explosions. So the research of this paper can be help to the design of steel structure explode resistance.

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50

Del Pezzo, E. "Discrimination of Earthquakes and Underwater Explosions Using Neural Networks". Bulletin of the Seismological Society of America 93, nr 1 (1.02.2003): 215–23. http://dx.doi.org/10.1785/0120020005.

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