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J. Mar. Sci. Eng., Volume 7, Issue 5 (May 2019)

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Cover Story (view full-size image) A scour identification method was developed based on the ambient vibration measurements of [...] Read more.
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Open AccessArticle
Prediction of Self-Propulsion Performance of Ship Model with Double L-Type Podded Propulsors and Conversion Method for Full-Scale Ship
J. Mar. Sci. Eng. 2019, 7(5), 162; https://doi.org/10.3390/jmse7050162
Received: 5 May 2019 / Revised: 23 May 2019 / Accepted: 23 May 2019 / Published: 27 May 2019
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Abstract
In this study, the self-propulsion performance of a ship model with double-L-type podded propulsors was predicted. Additionally, a conversion method for the performance of a full-scale ship was established based on the correction method published by the International Towing Tank Conference (ITTC) for [...] Read more.
In this study, the self-propulsion performance of a ship model with double-L-type podded propulsors was predicted. Additionally, a conversion method for the performance of a full-scale ship was established based on the correction method published by the International Towing Tank Conference (ITTC) for the scaling effect of a single podded propeller and research reports on pod tests conducted by different ship research institutes. The thrust deduction and wake fraction of the ship were also analyzed. Furthermore, the self-propulsion performance of a full-scale ship with double L-type pods was determined, the full- and model-scale ships compared in terms of their flow fields and pressure charts, and the influence of the scaling effect analyzed. In addition, the calculation results were compared with the conversion results of a full-scale ship, and the reliability of the method adopted for the performance estimation of a full-scale ship with double podded propulsors was verified. The findings reported herein can provide statistics and technical support for the design of L-type podded propulsors and their application in full-scale ships, which are of theoretical significance and practical value in the engineering domain. Full article
(This article belongs to the Special Issue Marine Propulsion)
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Open AccessArticle
A Numerical Study on the Impact of High-Frequency Winds on the Peru Upwelling System during 2014–2016
J. Mar. Sci. Eng. 2019, 7(5), 161; https://doi.org/10.3390/jmse7050161
Received: 7 May 2019 / Revised: 19 May 2019 / Accepted: 21 May 2019 / Published: 25 May 2019
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Abstract
The contribution of high-frequency wind to the Peruvian upwelling system during 2014–2016 was studied using the Regional Ocean Modeling System (ROMS), forced by four different temporal resolution (six-hourly, daily, weekly, and monthly) wind forcing. A major effect of the high-frequency wind is its [...] Read more.
The contribution of high-frequency wind to the Peruvian upwelling system during 2014–2016 was studied using the Regional Ocean Modeling System (ROMS), forced by four different temporal resolution (six-hourly, daily, weekly, and monthly) wind forcing. A major effect of the high-frequency wind is its warming of the water at all depths along the Peruvian coast. The mechanism for the temperature changes induced by high-frequency wind forcing was analyzed through heat budget analysis, which indicated a three-layer structure. Vertical advection plays a leading role in the warming of the mixed layer (0–25 m), and enhanced vertical mixing balances the warming effect. Analysis suggests that around the depths of 25–60 m, vertical mixing warms the water by bringing heat from the surface to deeper depths. In waters deeper than 60 m, the effect of vertical mixing is negligible. The differences among the oceanic responses in the sensitivity experiments suggest that wind forcing containing variabilities at higher than synoptic frequencies must be included in the atmospheric forcing in order to properly simulate the Peru upwelling system. Full article
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Open AccessArticle
Mechanics and Historical Evolution of Sea Level Blowouts in New York Harbor
J. Mar. Sci. Eng. 2019, 7(5), 160; https://doi.org/10.3390/jmse7050160
Received: 2 April 2019 / Revised: 29 April 2019 / Accepted: 8 May 2019 / Published: 23 May 2019
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Abstract
Wind-induced sea level blowouts, measured as negative storm surge or extreme low water (ELW), produce public safety hazards and impose economic costs (e.g., to shipping). In this paper, we use a regional hydrodynamic numerical model to test the effect of historical environmental change [...] Read more.
Wind-induced sea level blowouts, measured as negative storm surge or extreme low water (ELW), produce public safety hazards and impose economic costs (e.g., to shipping). In this paper, we use a regional hydrodynamic numerical model to test the effect of historical environmental change and the time scale, direction, and magnitude of wind forcing on negative and positive surge events in the New York Harbor (NYH). Environmental sensitivity experiments show that dredging of shipping channels is an important factor affecting blowouts while changing ice cover and removal of other roughness elements are unimportant in NYH. Continuously measured water level records since 1860 show a trend towards smaller negative surge magnitudes (measured minus predicted water level) but do not show a significant change to ELW magnitudes after removing the sea-level trend. Model results suggest that the smaller negative surges occur in the deeper, dredged modern system due to a reduced tide-surge interaction, primarily through a reduced phase shift in the predicted tide. The sensitivity of surge to wind direction changes spatially with remote wind effects dominating local wind effects near NYH. Convergent coastlines that amplify positive surges also amplify negative surges, a process we term inverse coastal funneling. Full article
(This article belongs to the Special Issue Coastal Hazards Related to Water)
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Open AccessArticle
Interdisciplinary Methodology to Extend Technology Readiness Levels in SONAR Simulation from Laboratory Validation to Hydrography Demonstrator
J. Mar. Sci. Eng. 2019, 7(5), 159; https://doi.org/10.3390/jmse7050159
Received: 8 March 2019 / Revised: 23 April 2019 / Accepted: 2 May 2019 / Published: 23 May 2019
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Abstract
This paper extends underwater SONAR simulation from laboratory prototype to real-world demonstrator. It presents the interdisciplinary methodology to advance the state of the art from level four to level seven on the technology readiness level (TRL) standard scale for measuring the maturity of [...] Read more.
This paper extends underwater SONAR simulation from laboratory prototype to real-world demonstrator. It presents the interdisciplinary methodology to advance the state of the art from level four to level seven on the technology readiness level (TRL) standard scale for measuring the maturity of innovations. While SONAR simulation offers the potential to unlock cost-effective personnel capacity building in hydrography, demonstration of virtualised survey-scale operations is a prerequisite for validation by practitioners. Our research approach uses the TRL framework to identify and map current barriers to the use of simulation to interdisciplinary solutions adapted from multiple domains. To meet the distinct challenges of acceptance tests at each level in the TRL scale, critical knowledge is incorporated from different branches of science, engineering, project management, and pedagogy. The paper reports the simulator development at each escalation of TRL. The contributions to simulator performance and usability at each level of advancement are presented, culminating in the first case study demonstration of SONAR simulation as a real-world hydrographic training platform. Full article
(This article belongs to the Special Issue Underwater Imaging)
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Open AccessFeature PaperArticle
Stochastic Modeling of Forces on Jacket-Type Offshore Structures Colonized by Marine Growth
J. Mar. Sci. Eng. 2019, 7(5), 158; https://doi.org/10.3390/jmse7050158
Received: 14 April 2019 / Revised: 10 May 2019 / Accepted: 13 May 2019 / Published: 22 May 2019
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Abstract
The present paper deals with the stochastic modeling of bio-colonization for the computation of stochastic hydrodynamic loading on jacket-type offshore structures. It relies on a multidisciplinary study gathering biological and physical research fields that accounts for uncertainties at all the levels. Indeed, bio-colonization [...] Read more.
The present paper deals with the stochastic modeling of bio-colonization for the computation of stochastic hydrodynamic loading on jacket-type offshore structures. It relies on a multidisciplinary study gathering biological and physical research fields that accounts for uncertainties at all the levels. Indeed, bio-colonization of offshore structures is a complex phenomenon with two major but distinct domains: (i) marine biology, whose processes are modeled with biomathematics methods, and (ii) hydrodynamic processes. This paper aims to connect these two domains. It proposes a stochastic model for the marine organism’s growth and then continues with transfers for the assessment of drag coefficient and forces probability density functions that account for marine growth evolution. A case study relies on the characteristics (growth and shape) of the blue mussel (Mytilus edulis) in the northeastern Atlantic. Full article
(This article belongs to the Special Issue Marine Structures)
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Open AccessArticle
Estimation of Coastal Currents Using a Soft Computing Method: A Case Study in Galway Bay, Ireland
J. Mar. Sci. Eng. 2019, 7(5), 157; https://doi.org/10.3390/jmse7050157
Received: 1 April 2019 / Revised: 14 May 2019 / Accepted: 14 May 2019 / Published: 20 May 2019
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Abstract
In order to obtain forward states of coastal currents, numerical models are a commonly used approach. However, the accurate definition of initial conditions, boundary conditions and other model parameters are challenging. In this paper, a novel application of a soft computing approach, random [...] Read more.
In order to obtain forward states of coastal currents, numerical models are a commonly used approach. However, the accurate definition of initial conditions, boundary conditions and other model parameters are challenging. In this paper, a novel application of a soft computing approach, random forests (RF), was adopted to estimate surface currents for three analysis points in Galway Bay, Ireland. Outputs from a numerical model and observations from a high frequency radar system were used as inputs to develop soft computing models. The input variable structure of soft computing models was examined in detail through sensitivity experiments. High correlation of surface currents between predictions from RF models and radar data indicated that the RF algorithm is a most promising means of generating satisfactory surface currents over a long prediction period. Furthermore, training dataset lengths were examined to investigate influences on prediction accuracy. The largest improvement for zonal and meridional surface velocity components over a 59-h forecasting period was 14% and 37% of root mean square error (RMSE) values separately. Results indicate that the combination of RF models with a numerical model can significantly improve forecasting accuracy for surface currents, especially for the meridional surface velocity component. Full article
(This article belongs to the Special Issue Radar Technology for Coastal Areas and Open Sea Monitoring)
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Open AccessArticle
Improved Double-Layer Soil Consolidation Theory and Its Application in Marine Soft Soil Engineering
J. Mar. Sci. Eng. 2019, 7(5), 156; https://doi.org/10.3390/jmse7050156
Received: 4 April 2019 / Revised: 16 May 2019 / Accepted: 16 May 2019 / Published: 18 May 2019
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Abstract
Marine soft soil foundation is a double-layer foundation structure with a crust layer and soft substratum. Moreover, it is common that there are various forms of drainage. Accordingly, based on Terzaghi’s consolidation theory and the continuous drainage boundary conditions theory of controllable drainage [...] Read more.
Marine soft soil foundation is a double-layer foundation structure with a crust layer and soft substratum. Moreover, it is common that there are various forms of drainage. Accordingly, based on Terzaghi’s consolidation theory and the continuous drainage boundary conditions theory of controllable drainage conditions, an improved double-layer soil consolidation theory considering continuous drainage boundary conditions was proposed. To improve the computational efficiency and accuracy, the Laplace transform and the Stehfest algorithm was used to deduce the numerical solution of the improved double-layer soil consolidation theory considering continuous drainage boundary conditions and to compile a computer program. Subsequently, the theory was validated and analyzed by the degenerated model of the perfectly permeable boundary conditions and the semi-permeable boundary conditions, respectively, which showed that this theory has higher accuracy. Simultaneously, the analysis of double-layer consolidation settlement under continuous drainage boundary conditions for marine soft soil foundation of Guangxi Binhai Highway was carried on. The result showed that the consolidation settlement calculated by the improved double-layer consolidation theory presented is basically consistent with the field measurement results, and that the correlation coefficient between them is higher. Accordingly, the research results can provide useful basic information for marine soft foundation engineering. Full article
(This article belongs to the Special Issue New Advances in Marine Engineering Geology)
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Open AccessArticle
Influence Mechanism of Different Flow Patterns on the Softening of Red-Bed Soft Rock
J. Mar. Sci. Eng. 2019, 7(5), 155; https://doi.org/10.3390/jmse7050155
Received: 15 April 2019 / Revised: 6 May 2019 / Accepted: 14 May 2019 / Published: 18 May 2019
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Abstract
As a typical representative of red beds, the softening and disintegration of red sandstone when it encounters water is an important cause of initiated engineering disasters. However, research on the softening of this kind of rock has mainly focused on the still water–rock [...] Read more.
As a typical representative of red beds, the softening and disintegration of red sandstone when it encounters water is an important cause of initiated engineering disasters. However, research on the softening of this kind of rock has mainly focused on the still water–rock interaction. There is still a lack of quantitative analysis and a mechanistic explanation for the basic experimental study of dynamic water–rock interactions. Therefore, based on the independently developed multifunctional open channel hydraulic test equipment, the still water was used as the reference by designing the saturation test of red sandstone under two typical flow patterns—laminar flow and turbulent flow—and combined with a three-dimensional numerical simulation; specifically, the chemical, physical and mechanical effects of different flow patterns on the softening of red sandstone are discussed, and the mechanism of the influence of different flow patterns on the softening of red sandstone was further revealed. The results show that under different flow patterns, as the flow of water increased, the alkalinity of the circulating solution became stronger, the speed of stabilization of the ion concentration became faster, the development of the microscopic structure of the corresponding rock became higher and the decrease in mechanical strength became greater. The flow state affects the processes of rock softening and breaking by acting on the rock from the three aspects of chemistry, physics and mechanics. The study makes up for the deficiency of the quantitative analysis index of rock softening under dynamic water conditions and further improves the influence mechanism of different flow patterns on soft rock softening in red beds under dynamic water conditions. This research also provides a specific method for the protection of estuarine and coastal bank slopes with rich red-bed soft rock dissection under different flow patterns. Full article
(This article belongs to the Section Coastal Engineering)
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Open AccessArticle
Parametric Study of Tsunamis Generated by Earthquakes and Landslides
J. Mar. Sci. Eng. 2019, 7(5), 154; https://doi.org/10.3390/jmse7050154
Received: 8 April 2019 / Revised: 8 May 2019 / Accepted: 10 May 2019 / Published: 17 May 2019
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Abstract
Tsunami generation and propagation mechanisms need to be clearly understood in order to inform predictive models and improve coastal community preparedness. Physical experiments, supported by mathematical models, can potentially provide valuable input data for standard predictive models of tsunami generation and propagation. A [...] Read more.
Tsunami generation and propagation mechanisms need to be clearly understood in order to inform predictive models and improve coastal community preparedness. Physical experiments, supported by mathematical models, can potentially provide valuable input data for standard predictive models of tsunami generation and propagation. A unique experimental set-up has been developed to reproduce a coupled-source tsunami generation mechanism: a two-dimensional underwater fault rupture followed by a submarine landslide. The test rig was located in a 20 m flume in the COAST laboratory at the University of Plymouth. The aim of the experiments is to provide quality data for developing a parametrisation of the initial conditions for tsunami generation processes which are triggered by a dual-source. During the test programme, the water depth and the landslide density were varied. The position of the landslide model was tracked and the free surface elevation of the water body was measured. Hence the generated wave characteristics were determined. For a coupled-source scenario, the generated wave is crest led, followed by a trough of smaller amplitude decreasing steadily as it propagates along the flume. The crest amplitude was shown to be influenced by the fault rupture displacement scale, whereas the trough was influenced by the landslide’s relative density. Full article
(This article belongs to the Special Issue Tsunami Science and Engineering II)
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Open AccessArticle
Design and Experiment of Clamper Used in Antarctic Subglacial Bedrock Drilling
J. Mar. Sci. Eng. 2019, 7(5), 153; https://doi.org/10.3390/jmse7050153
Received: 6 May 2019 / Revised: 9 May 2019 / Accepted: 13 May 2019 / Published: 17 May 2019
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Abstract
As a result of the severe natural environment with oxygen deficit in the Antarctic, using conventional manual work to screw and unscrew the drill pipe increases the labor intensity tremendously and causes an efficiency reduction. Therefore, it would be useful to design a [...] Read more.
As a result of the severe natural environment with oxygen deficit in the Antarctic, using conventional manual work to screw and unscrew the drill pipe increases the labor intensity tremendously and causes an efficiency reduction. Therefore, it would be useful to design a clamper inside the drilling shelter, which could help to assemble and disassemble the ice core barrel with screw connection. This paper describes the design of and experiments with the clamper inside the movable drilling shelter. A related testing stand was also designed and built to experiment on relationships between the clamper motor current versus clamping torque and force. Through experimental data collation and calculation analysis, the following conclusions could be drawn: (1) according to the rotary ability of the Ice and Bedrock Electromechanical Drill (IBED) to calculate and determine the torque of clamper, the clamping torque required to provide by the clamper is 100 N·m; (2) finite element simulation and analysis of the non-standard transmission chain showed that the mechanical reliability of the subparts; (3) the experimental results showed the range of the clamping force and clamping torque of the clamper. The clamping force and clamping torque increased with the increase of clamper DC motor current, presenting proportional linear relationships. The clamper can meet the clamping requirements of IBED for screwing, unscrewing, and clamping, which will be greatly helpful when it is tested in the field. Full article
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Open AccessArticle
Giant Submarine Landslide in the South China Sea: Evidence, Causes, and Implications
J. Mar. Sci. Eng. 2019, 7(5), 152; https://doi.org/10.3390/jmse7050152
Received: 6 April 2019 / Revised: 16 April 2019 / Accepted: 13 May 2019 / Published: 17 May 2019
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Abstract
Submarine landslides can be tremendous in scale. They are one of the most important processes for global sediment fluxes and tsunami generation. However, studies of prodigious submarine landslides remain insufficient. In this review paper, we compile, summarize, and reanalyze the results of previous [...] Read more.
Submarine landslides can be tremendous in scale. They are one of the most important processes for global sediment fluxes and tsunami generation. However, studies of prodigious submarine landslides remain insufficient. In this review paper, we compile, summarize, and reanalyze the results of previous studies. Based on this reanalysis, we discover the giant Baiyun–Liwan submarine slide in the Pearl River Mouth Basin, South China Sea. We describe three concurrent pieces of evidence from ~23 Ma to 24 Ma, the Oligocene–Miocene boundary, for this landslide: the shoreward shift of the shelf break in the Baiyun Sag, the slump deposition to the southeast, and the abrupt decrease in the accumulation rate on the lower continental slope. This landslide extends for over 250 km, and the total affected area of the slide is up to ~35,000–40,000 km2. The scale of the landslide is similar to that of the Storegga slide, which has long been considered to be the largest landslide on earth. We suggest that strike–slip movement along the Red River Fault and ridge jump of the South China Sea caused the coeval Baiyun–Liwan submarine slide. The identification of the giant landslide will promote the understanding of not only its associated geohazards but also the steep rise of the Himalayan orogeny and marine engineering. More attention needs to be paid to areas with repeated submarine landslides and offshore installations. Full article
(This article belongs to the Special Issue Coastal Geohazard and Offshore Geotechnics)
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Open AccessArticle
Mapping the Sandy Beach Evolution Around Seaports at the Scale of the African Continent
J. Mar. Sci. Eng. 2019, 7(5), 151; https://doi.org/10.3390/jmse7050151
Received: 19 April 2019 / Revised: 6 May 2019 / Accepted: 13 May 2019 / Published: 16 May 2019
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Abstract
In Africa, several new seaport developments are being considered. In sedimentary environments, such port developments can have adverse impacts on the evolution of adjacent coastlines. To learn from past port engineering practice, we created a unique database containing the coastline evolution and characteristics [...] Read more.
In Africa, several new seaport developments are being considered. In sedimentary environments, such port developments can have adverse impacts on the evolution of adjacent coastlines. To learn from past port engineering practice, we created a unique database containing the coastline evolution and characteristics of 130 existing African seaports. Whereas the systematic mapping of coastal impacts was previously hampered by data availability, innovative automated satellite image processing techniques have enabled us to intercompare ports at an unprecedented continental scale. We found large geographical differences with respect to the beach evolution. The total detected changes in the beach area between 1984 and 2018 totaled 44 km2, of which ca. 23 km2 is accretion and ca. 21 km2 is erosion. The top 10% “hotspot” ports account for more than 65% of these changes. These hotspots exhibit common characteristics, namely: they are located on open coastlines, have large alongshore sediment transport potential, and have large cross-shore breakwaters. Although these driving characteristics are well established in coastal engineering theory, our results indicate that the beaches adjacent to the existing seaports have been and remain seriously affected by these drivers. Our results can be used to inform beach maintenance strategies for existing seaports and to support planners and engineers to minimize long-term coastal impacts of port expansions and new port developments in Africa in the future. Full article
(This article belongs to the Section Coastal Engineering)
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Open AccessArticle
Variations in Winter Ocean Wave Climate in the Japan Sea under the Global Warming Condition
J. Mar. Sci. Eng. 2019, 7(5), 150; https://doi.org/10.3390/jmse7050150
Received: 26 April 2019 / Revised: 9 May 2019 / Accepted: 13 May 2019 / Published: 15 May 2019
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Abstract
Future variations in the ocean wave climate caused by global warming could affect various coastal issues. Using a third-generation wave model, this study produced projections of the ocean wave climate for winter around Japan, focusing on the Japan Sea side. Wave simulation forcing [...] Read more.
Future variations in the ocean wave climate caused by global warming could affect various coastal issues. Using a third-generation wave model, this study produced projections of the ocean wave climate for winter around Japan, focusing on the Japan Sea side. Wave simulation forcing (sea surface wind) was generated through five different global warming experiments. More than half the future wave projections showed an increasing tendency of the climatological mean significant wave height during winter. However, the maximum significant wave height did not show any clear tendency in future variation. The top 1% of significant wave heights and mean wave periods showed apparent increases in frequencies of higher/longer waves in three out of the five future projections. Frequency distributions of significant wave height, mean wave period, mean wavelength and wave direction showed various future variations (reduction of small ocean waves, increasing frequency of waves from the west). There are large uncertainties in future variations of wave climate in the Japan Sea, but the high probability of variations in daily wave climate is recognized, based on the future wave projections. Variations in daily wave climate are important because they could affect the topography and environment of the coast through long-term repetitive actions. Full article
(This article belongs to the Section Coastal Engineering)
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Open AccessArticle
Mathematical Modeling Framework of Physical Effects Induced by Sediments Handling Operations in Marine and Coastal Areas
J. Mar. Sci. Eng. 2019, 7(5), 149; https://doi.org/10.3390/jmse7050149
Received: 27 March 2019 / Revised: 9 May 2019 / Accepted: 10 May 2019 / Published: 15 May 2019
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Abstract
In recent years increasing attention has been paid to environmental effects that may result from marine dredging and disposal operations. In general, the fine-grained fraction of handled sediments can be dispersed far from the intervention site as a turbidity plume, depending on the [...] Read more.
In recent years increasing attention has been paid to environmental effects that may result from marine dredging and disposal operations. In general, the fine-grained fraction of handled sediments can be dispersed far from the intervention site as a turbidity plume, depending on the specific site and operational parameters. Starting from a literature review, this paper suggests standards for estimating and characterizing the sediment source term, for setting up far-field modeling studies and analyzing numerical results, with the aim of optimizing, also from an economic point of view, the different project, execution and monitoring phases. The paper proposes an integrated modeling approach for simulating sediment dispersion due to sediment handling operations in different marine-coastal areas (off-shore, near-shore and semi-enclosed basins). Attention is paid to the characterization of sediment source terms due to different operational phases (removal, transport and disposal). The paper also deals with the definition of accuracy level of modeling activities, with regard to the main physical processes characterizing the different marine–coastal areas and to the type of environmental critical issues near the intervention site (if any). The main relationships between modeling and monitoring are given for the different design and management phases to support the selection of appropriate technical alternatives and monitoring actions and to ensure the environmental compliance of the proposed interventions. Full article
(This article belongs to the Special Issue Marine Sediments: Processes, Transport and Environmental Aspects)
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Open AccessArticle
Performance Evaluation of Wave Input Reduction Techniques for Modeling Inter-Annual Sandbar Dynamics
J. Mar. Sci. Eng. 2019, 7(5), 148; https://doi.org/10.3390/jmse7050148
Received: 8 April 2019 / Revised: 5 May 2019 / Accepted: 8 May 2019 / Published: 15 May 2019
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Abstract
In process-based numerical models, reducing the amount of input parameters, known as input reduction (IR), is often required to reduce the computational effort of these models and to enable long-term, ensemble predictions. Currently, a comprehensive performance assessment of IR-methods is lacking, which hampers [...] Read more.
In process-based numerical models, reducing the amount of input parameters, known as input reduction (IR), is often required to reduce the computational effort of these models and to enable long-term, ensemble predictions. Currently, a comprehensive performance assessment of IR-methods is lacking, which hampers guidance on selecting suitable methods and settings in practice. In this study, we investigated the performance of 10 IR-methods and 36 subvariants for wave climate reduction to model the inter-annual evolution of nearshore bars. The performance of reduced wave climates is evaluated by means of a brute force simulation based on the full climate. Additionally, we tested how the performance is affected by the number of wave conditions, sequencing, and duration of the reduced wave climate. We found that the Sediment Transport Bins method is the most promising method. Furthermore, we found that the resolution in directional space is more important for the performance than the resolution in wave height. The results show that a reduced wave climate with fewer conditions applied on a smaller timescale performs better in terms of morphology than a climate with more conditions applied on a longer timescale. The findings of this study can be applied as initial guidelines for selecting input reduction methods at other locations, in other models, or for other domains. Full article
(This article belongs to the Section Coastal Engineering)
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Open AccessArticle
Energy Yield Assessment from Ocean Currents in the Insular Shelf of Cozumel Island
J. Mar. Sci. Eng. 2019, 7(5), 147; https://doi.org/10.3390/jmse7050147
Received: 9 April 2019 / Revised: 26 April 2019 / Accepted: 7 May 2019 / Published: 15 May 2019
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Abstract
Marine renewables represent a promising and innovative alternative source for satisfying the energy demands of growing populations while reducing the consumption of fossil fuels. Most technological advancements and energy yield assessments have focused on promoting the use of kinetic energy from tidal streams [...] Read more.
Marine renewables represent a promising and innovative alternative source for satisfying the energy demands of growing populations while reducing the consumption of fossil fuels. Most technological advancements and energy yield assessments have focused on promoting the use of kinetic energy from tidal streams with flow velocities higher than 2.0 m s−1. However, slower-moving flows from ocean currents are recently explored due to their nearly continuous and unidirectional seasonal flows. In this study, the potential of the Yucatan Current was analysed at nearshore sites over the insular shelf of Cozumel Island in the Mexican Caribbean. Field measurements were undertaken using a vessel-mounted Acoustic Doppler Current Profiler (ADCP) to analyse the spatial distribution of flow velocities, along with Conductivity-temperature-depth (CTD) profiles as well as data gathering of bathymetry and water elevations. Northward directed flow velocities were identified, with increasing velocities just before the end of the strait of the Cozumel Channel, where average velocities in the region of 0.88–1.04 m s−1 were recorded. An estimation of power delivery using horizontal axis turbines was undertaken with Blade Element Momentum theory. It was estimated that nearly 3.2 MW could be supplied to Cozumel Island, amounting to about 10% of its electricity consumption. Full article
(This article belongs to the Special Issue The Development of Marine Energy Extraction)
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Open AccessArticle
Experiment and Analysis of Submarine Landslide Model Caused by Elevated Pore Pressure
J. Mar. Sci. Eng. 2019, 7(5), 146; https://doi.org/10.3390/jmse7050146
Received: 1 April 2019 / Revised: 8 May 2019 / Accepted: 11 May 2019 / Published: 15 May 2019
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Abstract
Hydrate decomposition is an important potential cause of marine geological disasters. It is of great significance to understand the dynamic relationship between hydrate reservoir system and the overlying seabed damage caused by its decomposition. The purpose of this study is to understand the [...] Read more.
Hydrate decomposition is an important potential cause of marine geological disasters. It is of great significance to understand the dynamic relationship between hydrate reservoir system and the overlying seabed damage caused by its decomposition. The purpose of this study is to understand the instability and destruction mechanisms of a hydrated seabed using physical simulations and to discuss the effects of different geological conditions on seabed stability. By applying pressurized gas to the low permeability silt layer, the excess pore pressure caused by the decomposition of hydrate is simulated and the physical appearance process of the overlying seabed damage is monitored. According to the test results, two conclusions were drawn in this study: (1) Under the action of excess pore pressure caused by hydrate decomposition, typical phenomena of overlying seabed damage include pockmark deformation and shear–slip failure. In shallower or steeper strata, shear-slip failure occurs in the slope. The existence of initial crack in the stratum is the main trigger cause. In thicker formations or gentler slopes, the surface of the seabed has a collapse deformation feature. The occurrence of cracks in the deep soil layer is the main failure mechanism. (2) It was determined that the thickness and slope of the seabed, among other factors, affect the type and extent of seabed damage. Full article
(This article belongs to the Special Issue Participation of Gas Hydrate to Form Oil-Gas Deposit in the Seas)
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Open AccessArticle
Variability of Best-Estimate Flood Depth Return Periods in Coastal Louisiana
J. Mar. Sci. Eng. 2019, 7(5), 145; https://doi.org/10.3390/jmse7050145
Received: 30 March 2019 / Revised: 2 May 2019 / Accepted: 9 May 2019 / Published: 14 May 2019
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Abstract
Estimates of surge-based flood depth exceedance curves are useful to inform flood risk management strategies. Estimated return periods associated with flood depth exceedances naturally vary over time, even under assumptions of stationarity, due to the irreducible randomness associated with storm events as new [...] Read more.
Estimates of surge-based flood depth exceedance curves are useful to inform flood risk management strategies. Estimated return periods associated with flood depth exceedances naturally vary over time, even under assumptions of stationarity, due to the irreducible randomness associated with storm events as new observations accrue with each passing year. We empirically examine the degree to which best-estimates of coastal Louisiana floodplains have changed over time and consider implications for risk management policies. We generate variation in estimated 100-year flood depths by truncating a historical data set of observed tropical cyclones to end in years ranging from 1980 to 2016, adopting three procedures for updating various inputs to an existing flood risk model using the truncated data set to identify which factors are most important in driving variation in risk estimates over time. The landscape used for modeling hydrodynamics is kept constant, allowing us to isolate the impacts of randomness in storm occurrence from other factors. Our findings indicate that the 100-year floodplain extent has substantially expanded in populated areas since 1980 due to these effects. Due to the low frequency at which flood maps are updated, it is possible that thousands of coastal residents are misclassified as being outside of the 100-year floodplain relevant to flood insurance rates and other regulations. Full article
(This article belongs to the Special Issue Coastal Hazards Related to Water)
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Open AccessArticle
Geomorphological Processes and Environmental Interpretation at Espalmador islet (Western Mediterranean)
J. Mar. Sci. Eng. 2019, 7(5), 144; https://doi.org/10.3390/jmse7050144
Received: 3 April 2019 / Revised: 3 May 2019 / Accepted: 9 May 2019 / Published: 14 May 2019
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Abstract
This study presents a sedimentological and stratigraphical description of the Pleistocene deposits cropping out in Espalmador islet (Illes Pitiüses). Four major sedimentary facies including the succession of aeolian, marine, colluvial and edaphic environments are described. The sedimentological and stratigraphical analysis of these deposits [...] Read more.
This study presents a sedimentological and stratigraphical description of the Pleistocene deposits cropping out in Espalmador islet (Illes Pitiüses). Four major sedimentary facies including the succession of aeolian, marine, colluvial and edaphic environments are described. The sedimentological and stratigraphical analysis of these deposits allows the reconstruction of the coastal Pleistocene environmental and geomorphological history of the Espalmador islet. The coastal relief and the fluctuations of the sea level mainly control the Pleistocene coastal landscape evolution on Espalmador. Episodes of aeolian activity and dune formation related to a predominant northwestern wind direction can be linked to periods of low sea level where a high amount of marine sediment is exposed on the shelf platform. Full article
(This article belongs to the Special Issue Coastal Morphodynamics II)
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Open AccessArticle
Field Test on Buoyancy Variation of a Subsea Bottom-Supported Foundation Model
J. Mar. Sci. Eng. 2019, 7(5), 143; https://doi.org/10.3390/jmse7050143
Received: 29 March 2019 / Revised: 5 May 2019 / Accepted: 10 May 2019 / Published: 13 May 2019
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Abstract
The bottom-supported foundation is the most important component of offshore platforms, as it provides the major support to the upper structure. The buoyancy of the bottom-supported foundation is a critical issue in platform design because it counteracts parts of the vertical loads. In [...] Read more.
The bottom-supported foundation is the most important component of offshore platforms, as it provides the major support to the upper structure. The buoyancy of the bottom-supported foundation is a critical issue in platform design because it counteracts parts of the vertical loads. In this paper, a model box was designed and installed with earth pressure transducers and pore pressure transducers to simulate the sitting process of the bottom-supported foundation. The buoyancy acting on the model box was calculated on the basis of two different methods, i.e., the water pressure difference between top and bottom surface and the effective stress at the bottom of the model. Field tests with different sitting times were carried out on the saturated soft clay seabed. Numerical coupled analysis was performed to verify the dissipation of the excess pore pressure at the bottom of the model. The results showed that the buoyancy of the model could reach twice the calculated value of Archimedes’ law in the initial stage, however, it eventually stabilized near the theoretical value as the excess pore pressure dissipated. There was a slight fluctuation in buoyancy due to the phase lag of the pore pressure response caused by the low permeability of the seabed. Full article
(This article belongs to the Special Issue Coastal Geohazard and Offshore Geotechnics)
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Open AccessArticle
A Study on the Wind Energy Potential in the Romanian Coastal Environment
J. Mar. Sci. Eng. 2019, 7(5), 142; https://doi.org/10.3390/jmse7050142
Received: 19 March 2019 / Revised: 28 April 2019 / Accepted: 9 May 2019 / Published: 13 May 2019
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Abstract
At the European level, offshore wind projects are already considered a competitive market. Nevertheless, this is not yet the case of the enclosed sea basins, such as the Black Sea, where no offshore wind farm is operating at this moment. From this perspective, [...] Read more.
At the European level, offshore wind projects are already considered a competitive market. Nevertheless, this is not yet the case of the enclosed sea basins, such as the Black Sea, where no offshore wind farm is operating at this moment. From this perspective, the objective of the present work is to identify the most suitable sites where a wind project can be developed in the Romanian coastal areas. Various parameters, such as wind speed, water depth, distance to shore, and turbine performance, are considered. A picture of the local wind characteristics is first provided considering 20 years of reanalysis data, which cover the time interval from January 1998 to December 2017. The results indicated that the best sites to implement a wind project are located in the northern sector of the Black Sea, close to the Danube Delta. It was also noticed an important variation of the wind speed between onshore and 20 km offshore, for which an increase of about 55% was estimated. Full article
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Open AccessArticle
Numerical Analyses of Wave Generation and Vortex Formation under the Action of Viscous Fluid Flows over a Depression
J. Mar. Sci. Eng. 2019, 7(5), 141; https://doi.org/10.3390/jmse7050141
Received: 21 March 2019 / Revised: 4 May 2019 / Accepted: 4 May 2019 / Published: 12 May 2019
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Abstract
Transient free-surface deformations and evolving vortices due to the passage of flows over a submerged cavity are simulated. A two-dimensional stream function–vorticity formulation with a free-surface model is employed. Model results are validated against the limiting case of pure lid-driven cavity flow with [...] Read more.
Transient free-surface deformations and evolving vortices due to the passage of flows over a submerged cavity are simulated. A two-dimensional stream function–vorticity formulation with a free-surface model is employed. Model results are validated against the limiting case of pure lid-driven cavity flow with comparisons of the vortical flow pattern and velocity profiles. The verification of the free-surface computations are also carried out by comparing results with published potential flow solutions for cases of flows over a depressed bottom topography. The agreements are generally good. Investigations are extended to other viscous flow conditions, where the cavity is set to have the normalized dimension of one by one when scaled by the still water depth. The free-surface elevations and streamline patterns for cases with Froude numbers ranging from 0.5 to 1.1 and different Reynolds numbers (Re = 5000 and 500) are calculated. At the condition of near-critical flow (Fr ≈ 1.0), the phenomenon of upstream advancing solitons is produced. Viscous effects on the free-surface profile reveal that at a lower value of Re (e.g., Re = 500) larger advancing solitary waves are generated. Vortical flow patterns in the cavity are examined for the cases with Fr = 1.0 and various values of Re. When Re = 5000, the vortex pattern includes a primary and a weak, but dominated secondary vortices at the time reaching a nearly quasi-steady motion. For the case of lower Re (e.g., Re = 500), a steady-state vortex pattern can be established with a clockwise primary vortex mostly occupied inside the cavity. Full article
(This article belongs to the Special Issue Marine Structures)
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Open AccessArticle
Effect of Girder Spacing and Depth on the Solitary Wave Impact on Coastal Bridge Deck for Different Airgaps
J. Mar. Sci. Eng. 2019, 7(5), 140; https://doi.org/10.3390/jmse7050140
Received: 16 April 2019 / Revised: 6 May 2019 / Accepted: 7 May 2019 / Published: 11 May 2019
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Abstract
Coastal bridge damage has become a severe issue of concern in the recent past with the destruction of a considerable number of bridges under the impact of waves during tsunami and storm surges. These events have become more frequent, with waves reaching the [...] Read more.
Coastal bridge damage has become a severe issue of concern in the recent past with the destruction of a considerable number of bridges under the impact of waves during tsunami and storm surges. These events have become more frequent, with waves reaching the bridge deck and causing upliftment and destruction. Past studies have demonstrated the establishment of various theoretical equations which works well for the submerged deck and regular wave types but show much scatter and uncertainty in case of a deck that is above still water level (SWL). The present study aims to generate a solitary wave to represent an extreme wave condition like a tsunami in the numerical wave tank modeled using the open source computational fluid dynamics (CFD) model REEF3D and to study the vertical impact force on the coastal bridge deck. A parametric study is carried out for increasing wave heights, girders spacing and depth for varying airgaps to analyze the effect of these parameters on the peak vertical impact force. It is observed that increasing the girder spacing and girder depth is effective in reducing the peak vertical impact force for the cases considered. Full article
(This article belongs to the Special Issue Computational Fluid Dynamics for Ocean Surface Waves)
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Open AccessArticle
Storm Waves at the Shoreline: When and Where Are Infragravity Waves Important?
J. Mar. Sci. Eng. 2019, 7(5), 139; https://doi.org/10.3390/jmse7050139
Received: 30 March 2019 / Revised: 30 April 2019 / Accepted: 7 May 2019 / Published: 11 May 2019
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Abstract
Infragravity waves (frequency, f = 0.005–0.05 Hz) are known to dominate hydrodynamic and sediment transport processes close to the shoreline on low-sloping sandy beaches, especially when incident waves are large. However, in storm wave conditions, how their importance varies on different beach types, [...] Read more.
Infragravity waves (frequency, f = 0.005–0.05 Hz) are known to dominate hydrodynamic and sediment transport processes close to the shoreline on low-sloping sandy beaches, especially when incident waves are large. However, in storm wave conditions, how their importance varies on different beach types, and with different mixes of swell and wind-waves is largely unknown. Here, a new dataset, comprising shoreline video observations from five contrasting sites (one low-sloping sandy beach, two steep gravel beaches, and two compound/mixed sand and gravel beaches), under storm wave conditions (deep water wave height, H0 up to 6.6 m, and peak period, Tp up to 18.2 s), was used to assess: how the importance and dominance of infragravity waves varies at the shoreline? In this previously unstudied combination of wave and morphological conditions, significant infragravity swash heights (Sig) at the shoreline in excess of 0.5 m were consistently observed on all five contrasting beaches. The largest infragravity swash heights were observed on a steep gravel beach, followed by the low-sloping sandy beach, and lowest on the compound/mixed sites. Due to contrasting short wave breaking and dissipation processes, infragravity frequencies were observed to be most dominant over gravity frequencies on the low-sloping sandy beach, occasionally dominant on the gravel beaches, and rarely dominant on the compound/mixed beaches. Existing empirical predictive relationships were shown to parameterize Sig skillfully on the sand and gravel beaches separately. Deep water wave power was found to accurately predict Sig on both the sand and gravel beaches, demonstrating that, under storm wave conditions, the wave heights and periods are the main drivers of infragravity oscillations at the shoreline, with the beach morphology playing a secondary role. The exception to this was the compound/mixed beach sites where shoreline infragravity energy remained low. Full article
(This article belongs to the Special Issue Storm Erosion)
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Open AccessFeature PaperArticle
A Diesel Engine Modelling Approach for Ship Propulsion Real-Time Simulators
J. Mar. Sci. Eng. 2019, 7(5), 138; https://doi.org/10.3390/jmse7050138
Received: 31 March 2019 / Revised: 23 April 2019 / Accepted: 2 May 2019 / Published: 11 May 2019
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Abstract
A turbocharged diesel engine numerical model, suitable for real-time ship manoeuvre simulation, is presented in this paper. While some engine components (mainly the turbocharger, intercooler and manifolds) are modelled by a filling and emptying approach, the cylinder simulation is based on a set [...] Read more.
A turbocharged diesel engine numerical model, suitable for real-time ship manoeuvre simulation, is presented in this paper. While some engine components (mainly the turbocharger, intercooler and manifolds) are modelled by a filling and emptying approach, the cylinder simulation is based on a set of five-dimensional numerical matrices (each matrix is generated by means of a more traditional thermodynamic model based on in-cylinder actual cycle). The new cylinder calculation approach strongly reduces the engine transient computation time, making it possible to transform the simulation model into a real-time executable application. As a case study, the simulation methodology is applied to a high speed four stroke turbocharged marine diesel engine, whose design and off design running data are available from the technical sheet. In order to verify the suitability of the proposed model in real-time simulation applications, a yacht propulsion plant simulator is developed. Numerical results in ship acceleration and deceleration manoeuvres are shown, reducing the simulation running time of 99% in comparison with the corresponding in-cylinder actual cycle engine model. Full article
(This article belongs to the Special Issue Advances in Marine Dynamic Simulation)
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Open AccessArticle
Statistical Deviations in Shoreline Detection Obtained with Direct and Remote Observations
J. Mar. Sci. Eng. 2019, 7(5), 137; https://doi.org/10.3390/jmse7050137
Received: 29 March 2019 / Revised: 29 April 2019 / Accepted: 6 May 2019 / Published: 11 May 2019
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Abstract
Remote video imagery is widely used for shoreline detection, which plays a fundamental role in geomorphological studies and in risk assessment, but, up to now, few measurements of accuracy have been undertaken. In this paper, the comparison of video-based and GPS-derived shoreline measurements [...] Read more.
Remote video imagery is widely used for shoreline detection, which plays a fundamental role in geomorphological studies and in risk assessment, but, up to now, few measurements of accuracy have been undertaken. In this paper, the comparison of video-based and GPS-derived shoreline measurements was performed on a sandy micro-tidal beach located in Italy (central Tyrrhenian Sea). The GPS survey was performed using a single frequency, code, and carrier phase receiver as a rover. Raw measurements have been post-processed by using a carrier-based positioning algorithm. The comparison between video camera and DGPS coastline has been carried out on the whole beach, measuring the error as the deviation from the DGPS line computed along the normal to the DGPS itself. The deviations between the two dataset were examined in order to establish possible spatial dependence on video camera point of view and on beach slope in the intertidal zone. The results revealed that, generally, the error increased with the distance from the acquisition system and with the wash up length (inversely proportional to the beach slope). Full article
(This article belongs to the Special Issue Remote Sensing in Coastline Detection)
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Open AccessArticle
Reduction of Hydrodynamic Noise of 3D Hydrofoil with Spanwise Microgrooved Surfaces Inspired by Sharkskin
J. Mar. Sci. Eng. 2019, 7(5), 136; https://doi.org/10.3390/jmse7050136
Received: 4 April 2019 / Revised: 4 May 2019 / Accepted: 7 May 2019 / Published: 10 May 2019
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Abstract
Loud hydrodynamic noise is not only potentially harmful to the health of organisms in the ocean, but it is also a threat to the survival of underwater vehicles. Different from the general noise reduction technologies at present, a new idea for a flow-induced [...] Read more.
Loud hydrodynamic noise is not only potentially harmful to the health of organisms in the ocean, but it is also a threat to the survival of underwater vehicles. Different from the general noise reduction technologies at present, a new idea for a flow-induced noise reduction design with spanwise microgrooved surfaces inspired by sharkskin is introduced in this paper. Large eddy simulations (LES) combined with the Ffowcs Williams and Hawkings (FW-H) equation are adopted to simulate the hydrodynamic noise of the three-dimensional (3D) hydrofoil. The accuracy of the numerical predictions is checked against existing experimental data, achieving good agreement. With the increase of observing distance, the noise reduction effect at the trailing edge direction is gradually apparent, and a maximum noise reduction of up to 7.28 dB can be observed. It is seen from the noise spectra of the biomimetic hydrofoil that the main peaks are eliminated, and the noise level at high frequency is also decreased. The cause of noise reduction lies in the secondary vortex generated in the microgrooves, which hinder the process of turbulence, consume the energy of the flow, and weaken the intensity of turbulent burst. The results of this study provide a new way to design low-noise underwater structures with hydrofoils. Full article
(This article belongs to the Section Ocean Engineering)
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Open AccessArticle
Impact of Anthropogenic Climate Change on United States Major Hurricane Landfall Frequency
J. Mar. Sci. Eng. 2019, 7(5), 135; https://doi.org/10.3390/jmse7050135
Received: 29 November 2018 / Revised: 5 May 2019 / Accepted: 6 May 2019 / Published: 10 May 2019
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Abstract
Although anthropogenic climate change has contributed to warmer ocean temperatures that are seemingly more favorable for Atlantic hurricane development, no major hurricanes made landfall in the United States between 2006 and 2016. The U.S., therefore, experienced a major hurricane landfall drought during those [...] Read more.
Although anthropogenic climate change has contributed to warmer ocean temperatures that are seemingly more favorable for Atlantic hurricane development, no major hurricanes made landfall in the United States between 2006 and 2016. The U.S., therefore, experienced a major hurricane landfall drought during those years. Using the high-resolution Geophysical Fluid Dynamics Laboratory 25 km grid High-Resolution Forecast-Oriented Low Ocean Resolution (HiFLOR) global climate model, the present study shows that increases in anthropogenic forcing, due to increases in greenhouse gasses, are associated with fewer long-duration major hurricane landfall droughts in the U.S., which implies an increase in major hurricane landfall frequency. We create six different fixed-distance ‘buffers’ that artificially circle the United States coastline in 100 km radial increments and can compensate for the bias in hurricane landfall calculations with six-hourly datasets. Major hurricane landfall frequencies are computed by applying the buffer zones to the six-hourly observed and simulated storm track datasets, which are then compared with the observed recorded major hurricane frequencies. We found that the major hurricane landfall frequencies generated with the 200 km buffer using the six-hourly observed best-track dataset are most correlated with the observed recorded major hurricane landfall frequencies. Using HiFLOR with an implemented buffer system, we found less frequent projections of long-duration major hurricane landfall drought events in controlled scenarios with greater anthropogenic global warming, which is independent on the radius of the coastal buffer. These results indicate an increase in U.S. major hurricane landfall frequencies with an increase in anthropogenic warming, which could pose a substantial threat to coastal communities in the U.S. Full article
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Open AccessArticle
Dynamic Impedances of Offshore Rock-Socketed Monopiles
J. Mar. Sci. Eng. 2019, 7(5), 134; https://doi.org/10.3390/jmse7050134
Received: 1 March 2019 / Revised: 30 April 2019 / Accepted: 2 May 2019 / Published: 9 May 2019
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Abstract
With the development of offshore wind energy in China, more and more offshore wind turbines are being constructed in rock-based sea areas. However, the large diameter and thin-walled steel rock-socketed monopiles are very scarce at present, and both the construction and design are [...] Read more.
With the development of offshore wind energy in China, more and more offshore wind turbines are being constructed in rock-based sea areas. However, the large diameter and thin-walled steel rock-socketed monopiles are very scarce at present, and both the construction and design are very difficult. For the design, the dynamic safety during the whole lifetime of the wind turbine is difficult to guarantee. Dynamic safety of a turbine is mostly controlled by the dynamic impedances of the rock-socketed monopile, which are still not well understood. How to choose the appropriate impedances of the socketed monopiles so that the wind turbines will neither resonant nor be too conservative is the main problem. Based on a numerical model in this study, the accurate impedances are obtained for different frequencies of excitation, different soil and rock parameters, and different rock-socketed lengths. The dynamic stiffness of monopile increases, while the radiative damping decreases as rock-socketed depth increases. When the weathering degree of rock increases, the dynamic stiffness of the monopile decreases, while the radiative damping increases. Full article
(This article belongs to the Special Issue Coastal Geohazard and Offshore Geotechnics)
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Open AccessArticle
Ultrasound Assisted Adsorptive Removal of Cr, Cu, Al, Ba, Zn, Ni, Mn, Co and Ti from Seawater Using Fe2O3-SiO2-PAN Nanocomposite: Equilibrium Kinetics
J. Mar. Sci. Eng. 2019, 7(5), 133; https://doi.org/10.3390/jmse7050133
Received: 6 March 2019 / Revised: 25 April 2019 / Accepted: 3 May 2019 / Published: 9 May 2019
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Abstract
This work reports the preparation and application of Fe2O3-SiO2-PAN nanocomposite for the removal of Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+ [...] Read more.
This work reports the preparation and application of Fe2O3-SiO2-PAN nanocomposite for the removal of Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+, and Ti3+ from seawater. X-ray diffraction (XRD), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET) characterized the synthesized composite. The following experimental parameters (Extraction time, adsorbent mass and pH) affecting the removal of major and trace metals were optimized using response surface methodology (RSM). The applicability of the RSM model was verified by performing the confirmation experiment using the optimal condition and the removal efficiency ranged from 90% to 97%, implying that the model was valid. The adsorption kinetic data was described by the pseudo-second order model. The applicability of the materials was tested on real seawater samples (initial concentration ranging from 0.270–203 µg L−1) and the results showed satisfactory percentage efficiency removal that range from 98% to 99.9%. The maximum adsorption capacities were found to be 4.36, 7.20, 2.23, 6.60, 5.06, 2.60, 6.79, 6.65 and 3.00 mg g−1, for Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+, and Ti4+, respectively. Full article
(This article belongs to the Special Issue Nanomaterials Applied in Water Treatments)
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J. Mar. Sci. Eng. EISSN 2077-1312 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
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