Articles by Daniel Bar
Engineering Researcher, M.Sc student Numerical Modeling Team
2024
Wang, Gil; Bar, Daniel; Schreier, Sebastian
The potential of end-of-life ships as a floating seawall and the methodical use of gap resonance for wave attenuation Journal Article
In: Ocean Engineering, vol. 298, pp. 117246, 2024, ISSN: 0029-8018.
@article{WANG2024117246,
title = {The potential of end-of-life ships as a floating seawall and the methodical use of gap resonance for wave attenuation},
author = {Gil Wang and Daniel Bar and Sebastian Schreier},
url = {https://www.sciencedirect.com/science/article/pii/S0029801824005833},
doi = {https://doi.org/10.1016/j.oceaneng.2024.117246},
issn = {0029-8018},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {Ocean Engineering},
volume = {298},
pages = {117246},
abstract = {This study examines the potential of a new type of floating seawall, made up of retired large-scale oceangoing vessels, to be used in open water and exposed coastal areas. The main objectives of the research are to assess the effectiveness of the floating seawall concept, to determine the contribution of the gap resonance to wave attenuation, and to compare the results of physical tests with those obtained numerically using ANSYS-AQWA. The use of end-of-life ships in this way provides a unique opportunity to extend their life cycle and reduce the environmental and human health risks associated with the current practice of shipbreaking. The research focuses on a multimodule floating seawall configuration, where each module is composed of two hulls that are rigidly connected side by side, with a small gap to induce gap resonance. The results suggest that end-of-life ships can be used as a resource for the construction of floating seawalls for various marine applications. Furthermore, the results demonstrate the positive influence of the gap resonance on the wave attenuation capacity of the seawall, as well as the limitations of the numerical tool in providing realistic values in this region.},
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pubstate = {published},
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This study examines the potential of a new type of floating seawall, made up of retired large-scale oceangoing vessels, to be used in open water and exposed coastal areas. The main objectives of the research are to assess the effectiveness of the floating seawall concept, to determine the contribution of the gap resonance to wave attenuation, and to compare the results of physical tests with those obtained numerically using ANSYS-AQWA. The use of end-of-life ships in this way provides a unique opportunity to extend their life cycle and reduce the environmental and human health risks associated with the current practice of shipbreaking. The research focuses on a multimodule floating seawall configuration, where each module is composed of two hulls that are rigidly connected side by side, with a small gap to induce gap resonance. The results suggest that end-of-life ships can be used as a resource for the construction of floating seawalls for various marine applications. Furthermore, the results demonstrate the positive influence of the gap resonance on the wave attenuation capacity of the seawall, as well as the limitations of the numerical tool in providing realistic values in this region.
Wang, Gil; Bar, Daniel; Hooimeijer, Fransje; Schreier, Sebastian
Floating Urban Development—Sustainable Growth and Affordable Housing Proceedings Article
In: Ikoma, Tomoki; Tabeta, Shigeru; Lim, Soon Heng; Wang, Chien Ming (Ed.): Proceedings of the Third World Conference on Floating Solutions, pp. 81–100, Springer Nature Singapore, Singapore, 2024, ISBN: 978-981-97-0495-8.
@inproceedings{10.1007/978-981-97-0495-8_6,
title = {Floating Urban Development—Sustainable Growth and Affordable Housing},
author = {Gil Wang and Daniel Bar and Fransje Hooimeijer and Sebastian Schreier},
editor = {Tomoki Ikoma and Shigeru Tabeta and Soon Heng Lim and Chien Ming Wang},
doi = {https://doi.org/10.1007/978-981-97-0495-8_6},
isbn = {978-981-97-0495-8},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
booktitle = {Proceedings of the Third World Conference on Floating Solutions},
pages = {81–100},
publisher = {Springer Nature Singapore},
address = {Singapore},
abstract = {Driven by population growth and rural migration toward the cities, the demand for affordable housing continues to increase. However, due to the scarcity of urban development space—especially in coastal areas, the supply is limited. As increasing land availability is one of the most effective ways to reduce real estate costs, this interdisciplinary research explores the alternative of urban expansion toward the adjacent marine environment of coastal cities. It focuses on floating residential dwellings from both technological and urban planning perspective, aiming to include the waterfront of coastal cities as viable, sustainable, and affordable alternative for urban development. The research takes on one of the most expensive cities in the world, Tel Aviv-Yafo, as a case study for increasing the supply of affordable housing in addition to vital sustainable future growth in the adjacent marine environment.},
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pubstate = {published},
tppubtype = {inproceedings}
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Driven by population growth and rural migration toward the cities, the demand for affordable housing continues to increase. However, due to the scarcity of urban development space—especially in coastal areas, the supply is limited. As increasing land availability is one of the most effective ways to reduce real estate costs, this interdisciplinary research explores the alternative of urban expansion toward the adjacent marine environment of coastal cities. It focuses on floating residential dwellings from both technological and urban planning perspective, aiming to include the waterfront of coastal cities as viable, sustainable, and affordable alternative for urban development. The research takes on one of the most expensive cities in the world, Tel Aviv-Yafo, as a case study for increasing the supply of affordable housing in addition to vital sustainable future growth in the adjacent marine environment.
2023
Bar, Daniel; Drimer, Nitai
Preliminary Design Tools for Hydrodynamic Aspects of Submerged Impermeable Breakwaters Journal Article
In: Journal of marine science and engineering., vol. 11, no. 2, 2023, ISSN: 2077-1312.
@article{ctx12496847360003971,
title = {Preliminary Design Tools for Hydrodynamic Aspects of Submerged Impermeable Breakwaters},
author = {Daniel Bar and Nitai Drimer},
issn = {2077-1312},
year = {2023},
date = {2023-02-17},
urldate = {2023-02-17},
journal = {Journal of marine science and engineering.},
volume = {11},
number = {2},
publisher = {MDPI AG,},
address = {Basel, Switzerland :},
abstract = {The boundary element method (BEM) with Lagrangian formulation is a conceptually simple and efficient method for the simulation of nonlinear wave shoaling, with or without impermeable coastal structures, up to the wave breaking. However, in post-breaking flows, the domain is no longer simply connected, and the BEM is not efficient for the generation of a new free surface. Volumes of fluid (VOF) methods are made to track the fluid-free surfaces after breaking, but they are more numerically complex and less efficient relative to the BEM before breaking. This study presents a numerical model, named BELWF—boundary elements Lagrangian wave flume—for the mathematical simulation of two-dimensional wave flumes. The BELWF can simulate the hydrodynamics of wave shoaling over a coast profile, with submerged impermeable coastal structures of any geometry. The developed model is applied to simulate and study Geotube structures. The BELWF is validated by comparisons with OpenFOAM simulations. Both the BELWF and OpenFOAM simulations show that the most critical state, regarding the sliding stability of the Geotube, occurs, typically just before breaking, where the BELWF reasonably assesses the wave loads and the sliding stability. Hence, the BELWF is a valid and efficient method for the preliminary design of impermeable coastal structures. Finally, the BELWF is applied to simulate a practical design example of a complete shoaling process along a sloped shore with a Geotube structure at the shallow water, which develops a plunging breaker. The simulation well captures the critical event considering the sliding stability of the structure.},
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pubstate = {published},
tppubtype = {article}
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The boundary element method (BEM) with Lagrangian formulation is a conceptually simple and efficient method for the simulation of nonlinear wave shoaling, with or without impermeable coastal structures, up to the wave breaking. However, in post-breaking flows, the domain is no longer simply connected, and the BEM is not efficient for the generation of a new free surface. Volumes of fluid (VOF) methods are made to track the fluid-free surfaces after breaking, but they are more numerically complex and less efficient relative to the BEM before breaking. This study presents a numerical model, named BELWF—boundary elements Lagrangian wave flume—for the mathematical simulation of two-dimensional wave flumes. The BELWF can simulate the hydrodynamics of wave shoaling over a coast profile, with submerged impermeable coastal structures of any geometry. The developed model is applied to simulate and study Geotube structures. The BELWF is validated by comparisons with OpenFOAM simulations. Both the BELWF and OpenFOAM simulations show that the most critical state, regarding the sliding stability of the Geotube, occurs, typically just before breaking, where the BELWF reasonably assesses the wave loads and the sliding stability. Hence, the BELWF is a valid and efficient method for the preliminary design of impermeable coastal structures. Finally, the BELWF is applied to simulate a practical design example of a complete shoaling process along a sloped shore with a Geotube structure at the shallow water, which develops a plunging breaker. The simulation well captures the critical event considering the sliding stability of the structure.
2021
Knobler, Sagi; Bar, Daniel; Cohen, Rotem; Liberzon, Dan
Wave Height Distributions and Rogue Waves in the Eastern Mediterranean Journal Article
In: Journal of Marine Science and Engineering, vol. 9, no. 6, 2021, ISSN: 2077-1312.
@article{jmse9060660,
title = {Wave Height Distributions and Rogue Waves in the Eastern Mediterranean},
author = {Sagi Knobler and Daniel Bar and Rotem Cohen and Dan Liberzon},
url = {https://www.mdpi.com/2077-1312/9/6/660},
doi = {10.3390/jmse9060660},
issn = {2077-1312},
year = {2021},
date = {2021-01-01},
journal = {Journal of Marine Science and Engineering},
volume = {9},
number = {6},
abstract = {There is a lack of scientific knowledge about the physical sea characteristics of the eastern part of the Mediterranean Sea. The current work offers a comprehensive view of wave fields in southern Israel waters covering a period between January 2017 and June 2018. The analyzed data were collected by a meteorological buoy providing wind and wave parameters. As expected for this area, the strongest storm events occurred throughout October–April. In this paper, we analyze the buoy data following two main objectives—identifying the most appropriate statistical distribution model and examining wave data in search of rogue wave presence. The objectives were accomplished by comparing a number of models suitable for deep seawater waves. The Tayfun–Fedele third-order model showed the best agreement with the tail of the empirical wave height distribution. The examination of different statistical thresholds for the identification of rogue waves resulted in the detection of 109 unique waves, all of relatively low height. The characteristics of the detected rogue waves were examined, revealing that the majority of them presented crest-to-trough symmetry. This finding calls for a reevaluation of the crest amplitude being equal to or above 1.25, the significant wave height threshold which assumes rogue waves carry most of their energy in the crest.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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There is a lack of scientific knowledge about the physical sea characteristics of the eastern part of the Mediterranean Sea. The current work offers a comprehensive view of wave fields in southern Israel waters covering a period between January 2017 and June 2018. The analyzed data were collected by a meteorological buoy providing wind and wave parameters. As expected for this area, the strongest storm events occurred throughout October–April. In this paper, we analyze the buoy data following two main objectives—identifying the most appropriate statistical distribution model and examining wave data in search of rogue wave presence. The objectives were accomplished by comparing a number of models suitable for deep seawater waves. The Tayfun–Fedele third-order model showed the best agreement with the tail of the empirical wave height distribution. The examination of different statistical thresholds for the identification of rogue waves resulted in the detection of 109 unique waves, all of relatively low height. The characteristics of the detected rogue waves were examined, revealing that the majority of them presented crest-to-trough symmetry. This finding calls for a reevaluation of the crest amplitude being equal to or above 1.25, the significant wave height threshold which assumes rogue waves carry most of their energy in the crest.
