The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Liam Gannon - One of the best experts on this subject based on the ideXlab platform.
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Submerged aluminum cylinder response to close proximity underwater explosions a comparison of experiment and simulation
International Journal of Impact Engineering, 2019Co-Authors: Liam GannonAbstract:Abstract The response of a Submerged Structure to an underwater explosion (UNDEX) involves complex interactions between the Structure and surrounding fluid. This study describes a numerical modelling methodology for calculating the structural response of an internally stiffened Submerged aluminum cylinder to a close-proximity UNDEX. The simulations account for the effects of both the shock wave and bubble jetting on the deformation of the cylinder. The accuracy of the simulations is demonstrated by comparison of calculated pressure, bubble motion, structural displacement and strain with experimental measurements. The simulated migration and jetting of the gas bubble agrees well with experimental observations. The magnitude of calculated strains is consistent with measurements and the calculated depth of permanent deformation in the shell plating is within 3% of the experimental value.
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simulation of underwater explosions in close proximity to a Submerged cylinder and a free surface or rigid boundary
Journal of Fluids and Structures, 2019Co-Authors: Liam GannonAbstract:Abstract The response of a Submerged Structure to an underwater explosion (UNDEX) depends on highly nonlinear interactions between the Structure, nearby boundaries, the shock wave and the bubble of gaseous explosion products. These complex interactions may significantly influence the loads imparted to a Submerged Structure by an underwater explosion. This research presents the experimental validation of a coupled Eulerian–Lagrangian numerical modelling approach for simulating the interaction between an underwater explosion, a Submerged cylinder, and a free surface or rigid bottom. The three-dimensional simulations in account concurrently for shock wave propagation, cavitation, and gas bubble migration and jetting. The validated simulation methodology is employed to demonstrate how the presence of a Submerged cylinder influences bubble migration and its period of oscillation in the vicinity of a boundary.
Hui-ming Fang - One of the best experts on this subject based on the ideXlab platform.
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Wave height distributions around Submerged Structure in wave-current field
Engineering Analysis with Boundary Elements, 1997Co-Authors: Chung-ren Chou, Shinn-shan Yan, Hui-ming FangAbstract:Abstract Effects of Submerged Structure on a wave-current field are studied numerically by means of BEM. The potential flow field is assumed to be composed of a steady current potential and an unsteady wave potential, where the Dopler effect is taken into consideration. The current velocities affected by the Submerged Structures were determined by using the three-dimensional boundary element method. Dispersion relations affected by the presence of current are used to calculate the apparent wave frequencies. Wave height distributions in the wave-current field were estimated.
Arun Shukla - One of the best experts on this subject based on the ideXlab platform.
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Underwater explosive bubble interaction with an adjacent Submerged Structure
Journal of Fluids and Structures, 2021Co-Authors: Carlos Javier, Michael Galuska, Michael Papa, James Leblanc, Helio Matos, Arun ShuklaAbstract:Abstract An experimental and computational investigation was conducted to study the interaction between bubbles generated by an underwater explosive (UNDEX) and a nearby steel plate Structure. The experiments were performed for different standoff distances to investigate the interaction between the gas bubble and the rigid Structure. High-speed photography was utilized to capture the underwater explosive gas bubble’s behavior, and a series of pressure transducers were used to record the emitted pressure histories. The numerical simulations were performed with the Dynamic System Mechanics Advanced Simulation software, which is a full y coupled Eulerian–Lagrangian fluid–Structure interaction code. The numerical simulations were validated with the experiments in terms of the detonation pressure, structural surface pressures, and UNDEX gas bubble growth and collapse. Results show that the UNDEX standoff distance greatly influences the gas bubble’s shape, migration speed, bubble jetting behavior, and loading into its adjacent Structure. Moreover, the impulse generated by the shock wave on the plate surface proved to be small in comparison to the impulse generated by the collapse of the UNDEX gas bubble. The magnitude of impulse depends on standoff distance, collapse symmetry, and relative collapse location.
Bruno Castelle - One of the best experts on this subject based on the ideXlab platform.
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modeling the impact of the implementation of a Submerged Structure on surf zone sandbar dynamics
Journal of Marine Science and Engineering, 2019Co-Authors: Clement Bouvier, Bruno Castelle, Yann BalouinAbstract:Coastal defense strategies based on Structures are increasingly unpopular as they are costly, leave lasting scars on the landscape, and sometimes have limited effectiveness or even adverse impacts. While a clear improvement concerning aesthetic considerations using soft Submerged breakwater is undeniable, their design has often focused on wave transmission processes across the crest of the Structure, overlooking short- to medium-term morphodynamic responses. In this study, we used a time- and depth-averaged morphodynamic model to investigate the impact of the implementation of a Submerged breakwater on surf zone sandbar dynamics at the beach of Sete, SE France. The hydrodynamic module was calibrated with data collected during a field experiment using three current profilers deployed to capture rip-cell circulation at the edge of the Structure. The model showed good agreement with measurements, particularly for the longshore component of the flow (RMSE = 0.07 m/s). Results showed that alongshore differential wave breaking at the edge of the Submerged breakwater drove an intense (0.4 m/s) two-dimensional circulation for low- to moderate-energy waves. Simulations indicated that inner-bar rip channel development, which was observed prior to the Submerged reef implementation, was inhibited in the lee of the Structure as rip-cell circulation across the inner bar disappeared owing to persistently low-energy breaking waves. The cross-shore sandbar dynamics in the lee of the Structure were also impacted due to the drastic decrease of the offshore-directed flow over the inner-bar during energetic events. This paper highlights that implementation of a Submerged breakwater results in larges changes in nearshore hydrodynamics that, in turn, can affect overall surf zone sandbar behavior.
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video monitoring of sandbar shoreline response to an offshore Submerged Structure at a microtidal beach
Geomorphology, 2017Co-Authors: Clement Bouvier, Yann Balouin, Bruno CastelleAbstract:Abstract In early 2013, an 800-m long and 12-m wide Submerged breakwater with its crest in 2-m depth was implemented at the wave-dominated barred beach of Sete, SE France, to fight against erosion and submersion hazards. Daily video images from April 2011 to April 2016 covering an alongshore distance of 3.5 km are used to analyse the response of both the sandbar(s) and the shoreline to the Structure implementation. Results show that the breakwater had a profound impact on the nearshore system, both shoreward of the Structure and well away from it alongshore. A progressive rotation and linearisation of the sandbar was observed shoreward of the Submerged breakwater. This resulted in the splitting of the sandbar adjacent to the Structure during a net offshore sandbar migration event driven by a severe storm in December 2013. The typical formation of a salient or tombolo was not observed. Instead, shoreline coupled to the sandbar geometry, which resulted in a slight seaward migration of the shoreline in front of the Structure. Overall, this study highlights that the role of the sandbar is critical to shoreline response to the implementation of breakwaters on barred beaches.
Chung-ren Chou - One of the best experts on this subject based on the ideXlab platform.
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Wave height distributions around Submerged Structure in wave-current field
Engineering Analysis with Boundary Elements, 1997Co-Authors: Chung-ren Chou, Shinn-shan Yan, Hui-ming FangAbstract:Abstract Effects of Submerged Structure on a wave-current field are studied numerically by means of BEM. The potential flow field is assumed to be composed of a steady current potential and an unsteady wave potential, where the Dopler effect is taken into consideration. The current velocities affected by the Submerged Structures were determined by using the three-dimensional boundary element method. Dispersion relations affected by the presence of current are used to calculate the apparent wave frequencies. Wave height distributions in the wave-current field were estimated.
