The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Mark Sussman - One of the best experts on this subject based on the ideXlab platform.
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Adaptive solution techniques for simulating Underwater Explosions and implosions
2016Co-Authors: Samet Y Kadioglu, Mark SussmanAbstract:Underwater Explosions and implosion
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adaptive solution techniques for simulating Underwater Explosions and implosions
Journal of Computational Physics, 2008Co-Authors: Samet Y Kadioglu, Mark SussmanAbstract:Adaptive solution techniques are presented for simulating Underwater Explosions and implosions. The liquid is assumed to be an adiabatic fluid and the solution in the gas is assumed to be uniform in space. The solution in water is integrated in time using a semi-implicit time discretization of the adiabatic Euler equations. Results are presented either using a non-conservative semi-implicit algorithm or a conservative semi-implicit algorithm. A semi-implicit algorithm allows one to compute with relatively large time steps compared to an explicit method. The interface solver is based on the coupled level set and volume-of-fluid method (CLSVOF) M. Sussman, A second order coupled level set and volume-of-fluid method for computing growth and collapse of vapor bubbles, J. Comput. Phys. 187 (2003) 110-136; M. Sussman, E.G. Puckett, A coupled level set and volume-of-fluid method for computing 3D and axisymmetric incompressible two-phase flows, J. Comput. Phys. 162 (2000) 301-337]. Several Underwater explosion and implosion test cases are presented to show the performances of our proposed techniques.
Avihu Ginzburg - One of the best experts on this subject based on the ideXlab platform.
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spectral analysis of Underwater Explosions in the dead sea
Geophysical Journal International, 1998Co-Authors: Yefim Gitterman, Zvi Benavraham, Avihu GinzburgAbstract:The present study utilizes the Israel Seismic Network (ISN) as a spatially distributed multichannel system for the discrimination of low-magnitude events (ML < 2.5), namely earthquakes and Underwater Explosions in the Dead Sea. In order to achieve this, we began with the application of conventional single-station methods, such as spectral short-period ratios. We then applied a newly developed, network-oriented algorithm based on different spectral features of the seismic radiation from Underwater Explosions and earthquakes, i.e. spectral semblance statistics. Twenty-eight single-shot Underwater Explosions (UWEs) and 16 earthquakes in the magnitude range ML = 1.6–2.8, within distances of 10–150 km, recorded by the ISN, were selected for the analysis. The analysis is based on a smoothed (0.5 Hz window) Fourier spectrum of the whole signal (defined by the signal-to-noise criterion), without picking separate wave phases. It was found that the classical discriminant of the seismic energy ratio between the relatively low-frequency (1–6 Hz) and high-frequency (6–11 Hz) bands, averaged over an ISN subnetwork, showed an overlap between UWEs and earthquakes and cannot itself provide reliable identification. We developed and tested a new multistation discriminant based on the low- frequency spectral modulation (LFSM) method. In our case the LFSM is associated with the bubbling effect in Underwater Explosions. The method demonstrates a distinct azimuth-invariant coherency of spectral shapes in the low-frequency range (1–12 Hz) of short-period seismometer systems. The coherency of the modulated spectra for different ISN stations was measured by semblance statistics commonly used in seismic prospecting for phase correlation in the time domain. The modified statistics provided an almost complete separation between earthquakes and Underwater Explosions.
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Spectral analysis of Underwater Explosions in the Dead Sea
Geophysical Journal International, 1998Co-Authors: Yefim Gitterman, Zvi Ben-avraham, Avihu GinzburgAbstract:The present study utilizes the Israel Seismic Network (ISN) as a spatially distributed multichannel system for the discrimination of low-magnitude events (ML
Yefim Gitterman - One of the best experts on this subject based on the ideXlab platform.
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near source audiovisual hydroacoustic and seismic observations of dead sea Underwater Explosions
Combustion Explosion and Shock Waves, 2009Co-Authors: Yefim GittermanAbstract:Results of a study of hydroacoustic, acoustic, and seismic effects from a series of three large-scale chemical Explosions of 0.5, 2, and 5 tons, conducted in November, 1999 in the Dead Sea, are presented. The shots were detonated at a water depth of 70 m (485 m below the ocean level). The main objective of the experiment was calibration of seismic stations of the International Monitoring System in the Middle East, using accurate travel times and source phenomenology features of Underwater Explosions. The largest shot provided magnitude about 4 and was recorded at distances up to 3500 km. Near-source seismic and hydroacoustic observations obtained were utilized to estimate source parameters of the conducted Explosions. Based on the curve-fit equation of the time-pressure measurements, the direct shock wave energy was estimated as 30.8% of the total explosive energy. The TNT equivalent to the 5000 kg charge of the explosive used (Chenamon) was determined as 4010 kg, corresponding to the manufacturer’s estimate of the Chenamon energy as ≈80% TNT.
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spectral analysis of Underwater Explosions in the dead sea
Geophysical Journal International, 1998Co-Authors: Yefim Gitterman, Zvi Benavraham, Avihu GinzburgAbstract:The present study utilizes the Israel Seismic Network (ISN) as a spatially distributed multichannel system for the discrimination of low-magnitude events (ML < 2.5), namely earthquakes and Underwater Explosions in the Dead Sea. In order to achieve this, we began with the application of conventional single-station methods, such as spectral short-period ratios. We then applied a newly developed, network-oriented algorithm based on different spectral features of the seismic radiation from Underwater Explosions and earthquakes, i.e. spectral semblance statistics. Twenty-eight single-shot Underwater Explosions (UWEs) and 16 earthquakes in the magnitude range ML = 1.6–2.8, within distances of 10–150 km, recorded by the ISN, were selected for the analysis. The analysis is based on a smoothed (0.5 Hz window) Fourier spectrum of the whole signal (defined by the signal-to-noise criterion), without picking separate wave phases. It was found that the classical discriminant of the seismic energy ratio between the relatively low-frequency (1–6 Hz) and high-frequency (6–11 Hz) bands, averaged over an ISN subnetwork, showed an overlap between UWEs and earthquakes and cannot itself provide reliable identification. We developed and tested a new multistation discriminant based on the low- frequency spectral modulation (LFSM) method. In our case the LFSM is associated with the bubbling effect in Underwater Explosions. The method demonstrates a distinct azimuth-invariant coherency of spectral shapes in the low-frequency range (1–12 Hz) of short-period seismometer systems. The coherency of the modulated spectra for different ISN stations was measured by semblance statistics commonly used in seismic prospecting for phase correlation in the time domain. The modified statistics provided an almost complete separation between earthquakes and Underwater Explosions.
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Spectral analysis of Underwater Explosions in the Dead Sea
Geophysical Journal International, 1998Co-Authors: Yefim Gitterman, Zvi Ben-avraham, Avihu GinzburgAbstract:The present study utilizes the Israel Seismic Network (ISN) as a spatially distributed multichannel system for the discrimination of low-magnitude events (ML
Peter H Dahl - One of the best experts on this subject based on the ideXlab platform.
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Physical effects of sound exposure from Underwater Explosions on Pacific sardines (Sardinops sagax).
The Journal of the Acoustical Society of America, 2020Co-Authors: Peter H Dahl, A. Keith Jenkins, Brandon Casper, Sarah E. Kotecki, Victoria Bowman, Christiana Boerger, David R. Dall'osto, Matthew Babina, Arthur N. PopperAbstract:Explosions from activities such as construction, demolition, and military activities are increasingly encountered in the Underwater soundscape. However, there are few scientifically rigorous data on the effects of Underwater Explosions on aquatic animals, including fishes. Thus, there is a need for data on potential effects on fishes collected simultaneously with data on the received signal characteristics that result in those effects. To better understand potential physical effects on fishes, Pacific sardines (Sardinops sagax) were placed in cages at mid-depth at distances of 18 to 246 m from a single mid-depth detonation of C4 explosive (4.66 kg net explosive weight). The experimental site was located in the coastal ocean with a consistent depth of approximately 19.5 m. Following exposure, potential correlations between blast acoustics and observed physical effects were examined. Acoustic metrics were calculated as a function of range, including peak pressure, sound exposure level, and integrated pressure over time. Primary effects related to exposure were damage to the swim bladder and kidney. Interestingly, the relative frequency of these two injuries displayed a non-monotonic dependence with range from the explosion in relatively shallow water. A plausible explanation connecting swim bladder expansion with negative pressure as influenced by bottom reflection is proposed.
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sound exposure level and energy spectral density of Underwater Explosions in shallow water over a coral substrate off the southern coast of o ahu hawai i
Journal of the Acoustical Society of America, 2016Co-Authors: Alexander G Soloway, Peter H Dahl, Lee H ShannonAbstract:This work presents the sound exposure levels (SEL) and energy spectral densities (ESD) from Underwater Explosions measured in shallow water (10-18 m) at distances of 500 to 1500 m at the Pu’uloa Underwater Detonation Range off the southern coast of Oahu. Nine explosive charges, with TNT-equivalent weights of 2.2 to 8.6 kg, were detonated on a seabed characterized by a thin sand layer over limestone. The ESD of the measurements are characterized by high propagation loss in the frequency ranges 50 to 350 Hz. Previous studies have shown that this is a common characteristic of this environment with the upper and lower frequencies directly related to the geoacoustic properties of the seabed and the waveguide geometry. Unlike measurements collected in sandy environments, where SEL agreed with empirical predictions, the SEL for these measurements differ by up to 30 dB. To understand the mechanisms responsible for these lower than expected levels, a geoacoustic model for the seabed is developed using these freque...
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peak sound pressure and sound exposure level from Underwater Explosions in shallow water
Journal of the Acoustical Society of America, 2014Co-Authors: Alexander G Soloway, Peter H DahlAbstract:Experimental measurements of the peak pressure and sound exposure level (SEL) from Underwater Explosions collected 7 km off the coast of Virginia Beach, Virginia are presented. The peak pressures are compared to results from previous studies and a semi-empirical equation that is a function of measurement range and charge weight, and are found to be in good agreement. An empirical equation for SEL that similarly employs a scaling approach involving charge weight and range is also presented and shows promise for the prediction of SEL in shallow water.
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measurements of the peak pressure and sound exposure level from Underwater Explosions
Journal of the Acoustical Society of America, 2013Co-Authors: Alexander G Soloway, Peter H DahlAbstract:There is an interest by the Navy to determine the sound field produced by Underwater Explosions to minimize the impact on marine life during training exercises. This work presents measurements of Underwater Explosions collected 7 km off the coast of Virginia in shallow water (depth 14 m) with sound speed conditions considered approximately iso-speed. Explosive charges with TNT equivalent weight 0.1 to 6.0 kg (W) were deployed at approximately mid-water and bottom depths. Acoustic data were recorded using a 9 element vertical line array at range 430 m and single-element autonomous systems at ranges 170, 430, and 950 m. The peak pressures and sound exposure levels (SEL) are calculated from the data; at 430 m peak pressures as high as 220 dB re 1 μPa and SEL as high as 190 dB re 1 μPa2 s were measured. The peak pressures are compared to semi-empirical equations that are functions of range and W to the one-third power, such as Arons [J. Acoust. Soc. Am. 26, 343-346 (1954)], and both the peak pressures and SEL are compared to simulations obtained using the parabolic wave equation. [Research supported by Naval Facilities Engineering Command.]
Samet Y Kadioglu - One of the best experts on this subject based on the ideXlab platform.
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Adaptive solution techniques for simulating Underwater Explosions and implosions
2016Co-Authors: Samet Y Kadioglu, Mark SussmanAbstract:Underwater Explosions and implosion
-
adaptive solution techniques for simulating Underwater Explosions and implosions
Journal of Computational Physics, 2008Co-Authors: Samet Y Kadioglu, Mark SussmanAbstract:Adaptive solution techniques are presented for simulating Underwater Explosions and implosions. The liquid is assumed to be an adiabatic fluid and the solution in the gas is assumed to be uniform in space. The solution in water is integrated in time using a semi-implicit time discretization of the adiabatic Euler equations. Results are presented either using a non-conservative semi-implicit algorithm or a conservative semi-implicit algorithm. A semi-implicit algorithm allows one to compute with relatively large time steps compared to an explicit method. The interface solver is based on the coupled level set and volume-of-fluid method (CLSVOF) M. Sussman, A second order coupled level set and volume-of-fluid method for computing growth and collapse of vapor bubbles, J. Comput. Phys. 187 (2003) 110-136; M. Sussman, E.G. Puckett, A coupled level set and volume-of-fluid method for computing 3D and axisymmetric incompressible two-phase flows, J. Comput. Phys. 162 (2000) 301-337]. Several Underwater explosion and implosion test cases are presented to show the performances of our proposed techniques.
