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Offshore floating photovoltaic (FPV) systems are subjected to significant aerodynamic forces, especially during extreme wind conditions. Accurate estimation of these forces is crucial for the proper design of mooring lines and connection systems. In this study, detailed CFD simulations were performed for various PV panel configurations, and using these CFD simulation correlations were developed to estimate lift and drag forces as a function of the number of panels. These correlations provide valuable tools for designing large-scale FPV systems with multiple PV modules. Additionally, this study investigates the potential of using breakwaters to reduce aerodynamic forces on FPV systems. Breakwaters, typically used to mitigate wave impacts, can also serve as wind barriers, significantly reducing wind forces before they reach the FPV array. Aerodynamic simulations with and without a breakwater were conducted using CFD to assess this effect. The results show a substantial reduction in lift and drag coefficients, especially for angles of attack up to 10 degrees, demonstrating the effectiveness of the breakwater in protecting the FPV system. However, beyond this threshold, the effectiveness of the breakwater of 2 m reduces. These findings highlight the importance of strategic breakwater placement and heights and their role in enhancing FPV system resilience. The insights gained from this study are critical for optimizing breakwater design and placement, ensuring the structural integrity and performance of FPV systems in varying environmental conditions. The data generated will also contribute to future design improvements for floating PV systems. [ABSTRACT FROM AUTHOR]

This paper deals with numerical modelling of wave and current patterns in the coastal city of Genaveh port (Bushehr province, Persian Gulf) with a sloping breakwater. Three breakwater arm patterns were defined based on the studied area's marine currents. Meteorological model wind statistics (ECMWF) and wave statistics (ISWM) and data from monitoring and simulation projects of the northern coasts of the Persian Gulf were used to model the hydrodynamics of the study area after the breakwater construction. In this numerical modelling, mike 21-SW and HD modules were employed to simulate the wave patterns near the three proposed breakwater arms. Based on observations of the hydrodynamic condition and with consideration of the design wave exhibiting a 100-year return period, it is indicated that an optimal pattern would yield significant wave heights and wave speeds of 0.2 m and 0.25 m/s, respectively, within both the existing and newly constructed harbour basins. [ABSTRACT FROM AUTHOR]

The implementation of nature-based solutions (NbS), including living shorelines, to mitigate estuarine habitat loss is increasing at a pace exceeding the evaluation of their long-term success. Constructed oyster reefs (CORs) made of shell, concrete, stone, and other materials are one living shoreline tactic that is widely utilized, yet few studies have been conducted to understand the development of CORs within the context of both physical and ecological parameters over longer time scales (4 + years). A COR-based living shoreline project at the Gandy’s Beach Preserve (GBP) in Delaware Bay, NJ, USA, had dual goals of coastal protection and habitat provisioning, which prompted the development of a goal-driven monitoring framework to track project objectives. Methods were developed to quantify the following multi-disciplinary metrics over 7 years: elevations of CORs, waves (height, period, and direction), shoreline elevations, change in extent of vegetation patches, oyster density and size, nekton richness and community composition, and horseshoe crab impingement. The CORs met most of their habitat provisioning objectives as they were colonized by a multi-generational population of shellfish and created habitat for nekton, while posing negligible hazards to horseshoe crabs. However, none of the coastal protection objectives was fully achieved including material stability, wave attenuation, and sediment elevation increase. Results highlight the value of longer-term monitoring to understand performance and the need to match the scale and type of NbS tactic(s) with both the scale of the landscape and the site-specific hydrodynamic conditions to meet project goals. [ABSTRACT FROM AUTHOR]

Experimental and numerical studies were conducted to assess the stability of the breakwater of Fujairah Port on the east coast of the United Arab Emirates against tsunamis. Experiments were conducted on a 1:50 scale and numerical analysis was done with the formulas of tsunami-breakwater interaction. The experimental observations corroborated the numerical results. The breakwater was safe up to 3 m of tsunami height, but when the tsunami height increased from 3 m to 6 m, the percentage damage to the leeside (portside) of the breakwater increased compared to the seaside. The leeside of the breakwater was deformed by tsunami overtopping and seepage — the breakwater cross-section reshaped from trapezoidal to quasi-triangular at 6 m tsunami impact, however, the breakwater was not breached. Rubbles of the breakwater were transported due to sliding, rolling, and saltation by overtopping and seepage. For 6 m tsunami height, rubbles from the seaside rolled over up with saltation and transported to the leeside. A large number of rubbles were transported landward from the leeside of the breakwater but a few were displaced offshore from the seaside. [ABSTRACT FROM AUTHOR]

Abstract The present work investigates the water wave interaction with bottom-standing thick porous trapezoidal-shaped structures and shore-side vertical rigid wall in the presence of uniform ocean currents. This study has been done to understand the impact of different physical parameters like friction, porosity, and ocean currents along with different structural parameters (width and height) on different phenomena like wave energy reflection, wave forces, wave energy dissipation, etc. The quadratic boundary element method-based numerical technique has been used to solve the boundary value problem. The structural porosity is modeled using Sollitt and Cross’s model of water wave interaction with thick porous structures. Several results associated with the wave energy reflection and energy dissipation have been analyzed. Also, the wave force exerted by the incoming waves has been investigated to check the stability and sustainability of the right vertical rigid wall and porous structure. The Doppler-shift effect is observed in wave transformation characteristics due to the presence of ocean currents. The impact of following and opposing ocean currents can be seen in the graph of wave energy reflection, dissipation, and wave forces. The periodic patterns can be observed clearly in wave characteristics like wave energy reflection, dissipation, and wave forces when plotted against the non-dimensional separation gap between the porous breakwater and shore-side rigid seawall.

A dual-pontoon WEC-breakwater system is proposed to optimise space utilisation and reduce construction costs by integrating wave energy converters (WECs) with breakwaters. Previous parametric studies on the dimensions and layout of WECs have primarily used potential flow theories, often neglecting the viscous effects in wave–pontoon interactions. In this research, I employ a fully nonlinear viscous model, OpenFOAM®, to address these limitations. I examine multiple parameters, including the gap width between the pontoons, the draft, and the structure breadth, to assess their impact on the functional performance of this hybrid system. Furthermore, I discuss the accurate hydrodynamic performance of waves interacting with multiple floating structures and explore how various parameters influence the dual-pontoon WEC-breakwater integrated system's functionality. I discuss a novel analysis of the effective frequency bandwidth, considering both wave energy conversion efficiency and wave attenuation efficiency, to reflect the overall performance of the integrated system. This paper investigates wave–structure interactions and suggests optimisation strategies for the WEC-breakwater integrated system. [ABSTRACT FROM AUTHOR]

Wave energy conversion holds promise for renewable energy, but challenges like high initial costs hinder commercialization. Integrating wave-energy converters (WECs) into shore-protection structures creates dual-function structures for both electricity generation and coastal protection. Oscillating water columns (OWCs) have been well studied in the past with their simple generation mechanism and their out-of-water power take-off (PTO) system, which can minimize bio-fouling effects and maintenance costs compared to other submerged WECs. In addition, a slotted barrier allows for better circulation behind the breakwater while dissipating incoming wave energy through viscous damping. This study examines the performance of a new design which combines an OWC with a slotted breakwater. Small-scale (1:49) laboratory tests were performed with a piston-type wave generator. The performance is evaluated in terms of wave transmission, wave energy extraction, and wave loading under various wave conditions while focusing on the effects of the porosity of the slotted barrier and tide level changes. Results show that under larger waves, a decreasing wave transmission, increasing power extraction from the OWC, and energy dissipation from the slotted barrier are observed. On the other hand, under increasing wavelengths, wave transmission is observed to be constant; this is important for harbor design, which means that the breakwater is effective under a wider range of wavelengths. Porosity allows for more transmission while inducing less horizontal force on the structure. [ABSTRACT FROM AUTHOR]

This study numerically analyzes a submerged horizontal plate (SHP) device subjected to both regular and irregular waves. This device can be used either as a breakwater or a wave energy converter (WEC). The WaveMIMO methodology was applied for the numerical generation and wave propagation of the sea state of the Rio Grande coast in southern Brazil. The finite volume method was employed to solve conservation equations for mass, momentum, and volume fraction transport. The volume of fluid model was employed to handle the water-air mixture. The SHP length (Lp) effects were carried out in five cases. Results indicate that relying solely on regular waves in numerical studies is insufficient for accurately determining the real hydrodynamic behavior. The efficiency of the SHP as a breakwater and WEC varied depending on the wave approach. Specifically, the SHP demonstrates its highest breakwater efficiency in reducing wave height at 2.5Lp for regular waves and 3Lp for irregular waves. As a WEC, it achieves its highest axial velocity at 3Lp for regular waves and 2Lp for irregular waves. Since the literature lacks studies on SHP devices under the incidence of realistic irregular waves, this study significantly contributes to the state of the art. [ABSTRACT FROM AUTHOR]

The present study deals with the surface gravity wave interaction of a submerged composite wavy porous plate in the presence of a tunnel placed at a finite distance under the assumption of small amplitude theory and a two-dimensional framework. To solve the boundary value problem, a numerical method using the multi-domain boundary element method (MDBEM) is implemented. Hydrodynamic characteristics of interest such as reflection coefficient and transmission coefficient are computed and studied for a wide range of dimensionless wavenumber and relative plate lengths. Various parametric studies are conducted to emphasize the effect of structural parameters like the number of relative ripple wavelengths, relative ripple amplitude, and relative submergence depth. Dimensionless wave force coefficients acting on the plate and the tunnel are calculated and investigated. The study reveals that the presence of composite wavy porous plate has a significant effect in the mitigation of wave-exerted force on the tunnel. Optimized results are shown for the efficient design of coupled breakwater and tunnel models, which can be used beneficially to protect against the severity of wave action in similar applications of ocean engineering in marine environments. [ABSTRACT FROM AUTHOR]

The present work investigates the water wave interaction with bottom-standing thick porous trapezoidal-shaped structures and shore-side vertical rigid wall in the presence of uniform ocean currents. This study has been done to understand the impact of different physical parameters like friction, porosity, and ocean currents along with different structural parameters (width and height) on different phenomena like wave energy reflection, wave forces, wave energy dissipation, etc. The quadratic boundary element method-based numerical technique has been used to solve the boundary value problem. The structural porosity is modeled using Sollitt and Cross's model of water wave interaction with thick porous structures. Several results associated with the wave energy reflection and energy dissipation have been analyzed. Also, the wave force exerted by the incoming waves has been investigated to check the stability and sustainability of the right vertical rigid wall and porous structure. The Doppler-shift effect is observed in wave transformation characteristics due to the presence of ocean currents. The impact of following and opposing ocean currents can be seen in the graph of wave energy reflection, dissipation, and wave forces. The periodic patterns can be observed clearly in wave characteristics like wave energy reflection, dissipation, and wave forces when plotted against the non-dimensional separation gap between the porous breakwater and shore-side rigid seawall. [ABSTRACT FROM AUTHOR]

This paper aims to use deep learning algorithms to identify and study the stability of breakwater armor blocks. It introduces a posture identification model for fender blocks using a Mask Region-based Convolutional Neural Network (R-CNN), which has been enhanced by considering factors affecting breakwater fender blocks. Furthermore, a wave prediction model for breakwaters is developed by integrating Bidirectional Encoder Representations from Transformers (BERTs) with Bidirectional Long Short-Term Memory (BiLSTM). The performance of these models is evaluated. The results show that the accuracy of the Mask R-CNN and its comparison algorithms initially increases and then decreases with higher Intersection Over Union (IOU) thresholds, peaking at 95.16% accuracy at an IOU threshold of 0.5. The BERT-BiLSTM wave prediction model maintains a loss value around 0.01 and an accuracy of approximately 90.00%. These results suggest that the proposed models offer more accurate stability assessments of breakwater armor blocks. By combining the random forest prediction model with BiLSTM, the wave characteristics and fender posture can be predicted better, offering reliable decision support for breakwater engineering. [ABSTRACT FROM AUTHOR]

The object of research is permeable vertical walls (breakwaters) with different degrees of permeability. This paper reports the results of experimental research into the interaction of gravity waves with models of permeable vertical walls (breakwaters), which were formed from cylindrical piles of circular cross-section. With the help of visual and instrumental studies, the features of interaction of surface gravity waves with permeable vertical walls of different permeability have been identified. The degree of wave transformation by these walls was also determined in the form of reflection, transmission, and dissipation coefficients of wave energy. It was established that with a decrease in the permeability of the vertical wall and an increase in the steepness of the initial wave and a decrease in its period, the height of the reflected wave increased. The pattern of the transmitted wave height had the opposite trend. It was determined that the wave reflection coefficient increased with a decrease in the permeability of the vertical wall and the steepness of the initial wave. The wave transmission coefficient had the opposite trend, namely, it increased with increasing wall permeability and with decreasing steepness of the initial wave. The gravity wave energy dissipation coefficient decreased with increasing vertical wall permeability, but for waves with a significant steepness hi/λ>0.038, a decrease in the wave energy dissipation coefficient was observed for walls with low permeability and the appearance of extreme values of this coefficient. Thus, features in the interaction of surface gravity waves with permeable vertical walls (breakwaters) of different permeability have been researched and the degree of wave transformation by these walls has been determined, which could make it possible to effectively design and operate permeable vertical walls as coastal protection structures. [ABSTRACT FROM AUTHOR]

Surface gravity wave interaction of composite wavy porous plate is studied by developing a numerical model using the boundary element method in the context of two-dimensional linear potential theory. Bragg scattering phenomenon is studied by considering the linearized pressure drop condition known as Darcy's law passing through the porous structure. Numerical results are obtained through the boundary element method for the special limiting case of the existing previous literature to authenticate the accuracy of the numerical solution. The influence of wave and structural design parameters such as the number of ripple wavelengths of the wavy plate, relative plate length, structural porosities, and relative submergence depth on hydrodynamics properties such as reflection, transmission, horizontal wave load, and vertical wave coefficients are discussed. The study results of composite wavy porous plate indicate improved hydrodynamic performance as compared to the horizontal porous plate and wavy porous plate. This study is significant for practical applications in coastal engineering environments. [ABSTRACT FROM AUTHOR]

An oscillating buoy (OB) could function simultaneously as a wave energy converter and a breakwater. In this work, a numerical study is conducted to assess the ability of the buoy to perform both aforementioned tasks by quantitatively and qualitatively assessing its hydrodynamic performance. The computational fluid dynamics solver used for the numerical study is ANSYS Fluent, which uses Reynolds-averaged Navier-Stokes equations and Volume of Fluid method for the design and simulation of the numerical model, which consists of a rectangular OB that floats on the surface of a numerical wave tank. First, a total of six independent studies, namely the time, meshing, damping, overset geometry, flow viscosity, and spatial studies, were conducted for validation purposes. Second, calculation and analysis of the heave and transmission coefficients and vorticity magnitude were conducted to assess the hydrodynamic performance. Results of independent studies show cases with a high degree of accuracy to the experimental model, whereas results for hydrodynamic performance show a generally increasing heave movement of OB and transmission coefficient across the range of wave periods studied. Meanwhile, the vorticity magnitude flow fields show at least two vortices for all wave periods studied, except for the shortest two wave periods.

The numerical hydrodynamic experiments on SolidWorks modeling of a pile grillage made it possible to determine the loads on and the reactions of structures taking into account the time factor. The grillage design is optimized so that the distribution of pressure over the lateral surface of the piles is uniform. [ABSTRACT FROM AUTHOR]

As a key infrastructure, port breakwaters are prone to deformation and damage due to their special geographical location, unique geological conditions, and complex construction materials, resulting in extremely complex operating environments and enormous risks. In order to detect the current situation of port breakwaters and surrounding riprap, a multi sensor information fusion water -land integrated measurement method is proposed. This method includes equipment such as unmanned aerial vehicle aerial photography system, multi beam bathymetry system, portable side scan sonar, and shallow layer profiler system. The collected 3D point cloud, boundary line, seabed mud layer thickness, and other data are combined with ICP algorithm for data fusion processing, more accurate measurement data can be obtained, and the advantages of different sensors are complementary. This water -land integrated measurement method can more effectively and intuitively understand the changes in water structures and the erosion situation of underwater engineering, and provide effective technical support for better evaluation and monitoring of the status of breakwaters. [ABSTRACT FROM AUTHOR]

Wind is a significant factor influencing the stability of breakwater armor stones. However, few existing studies have considered the effects of wind on these structures. In this study, two-dimensional laboratory experiments were conducted to examine the effect of wind on the stability of breakwater armor stones. The stability factor ( K D ) of the armor stone, fluid velocity, runup, and rundown were observed under the action of waves and winds. A wind turbine was installed in front of the physical model of the breakwater to generate extreme wind conditions of 5.5 and 12 m/s. The results showed that K D decreased by 42.18% at 5.5 m/s and 57.82% at 12 m/s compared with that without wind. The maximum runup and rundown heights increased with wind velocity, following a Rayleigh distribution. The fluid velocity distribution conformed to a normal distribution, with the mean velocity directed offshore. Many studies have suggested that runup, rundown, and fluid velocity are the main factors affecting the stability of breakwater armor stones. The analysis revealed that wind affects these factors and lowers the stability coefficient. These wind-induced hydrodynamic changes suggest the need for a detailed hydrodynamic review of wind-wave conditions. [ABSTRACT FROM AUTHOR]

In this paper, the main studies and results of physical modeling obtained during the evaluation of engineering solutions for improving the pedestrian embankment are presented. [ABSTRACT FROM AUTHOR]

Offshore floating photovoltaic (FPV) systems are subjected to significant aerodynamic forces, especially during extreme wind conditions. Accurate estimation of these forces is crucial for the proper design of mooring lines and connection systems. In this study, detailed CFD simulations were performed for various PV panel configurations, and using these CFD simulation correlations were developed to estimate lift and drag forces as a function of the number of panels. These correlations provide valuable tools for designing large-scale FPV systems with multiple PV modules. Additionally, this study investigates the potential of using breakwaters to reduce aerodynamic forces on FPV systems. Breakwaters, typically used to mitigate wave impacts, can also serve as wind barriers, significantly reducing wind forces before they reach the FPV array. Aerodynamic simulations with and without a breakwater were conducted using CFD to assess this effect. The results show a substantial reduction in lift and drag coefficients, especially for angles of attack up to 10 degrees, demonstrating the effectiveness of the breakwater in protecting the FPV system. However, beyond this threshold, the effectiveness of the breakwater of 2 m reduces. These findings highlight the importance of strategic breakwater placement and heights and their role in enhancing FPV system resilience. The insights gained from this study are critical for optimizing breakwater design and placement, ensuring the structural integrity and performance of FPV systems in varying environmental conditions. The data generated will also contribute to future design improvements for floating PV systems.

The construction of new breakwaters in Anzali port has had a significant impact on the water body of the Anzali international lagoon. The Anzali wetland is under threat from sediment influx from mountainous regions, and the study used satellite image processing to demonstrate how the construction of new breakwaters impedes the natural transfer of sediment from the lagoon to the sea. The methodology employed a hybrid approach combining two methods: normal water index (MNDWI) and supervised classification (SVM) to detect sediment accumulation in the wetland water zone. Following the construction of new breakwaters in 2009, an island formed and expanded exponentially in parts of Sorkhankol Wildlife Sanctuary's water body. This phenomenon is attributed to decreased water flow caused by increased cross-section current and volume of water, creating a dam-like function against channel flow leading to the sea. Consequently, sediments and suspended loads settle in Sorkhankol's water zone, leading to an increase in island area from 0.39 hectares to over 26 hectares during the studied period. Result showed Kappa coefficients by SVM algorithm for years 2002, 2010, 2012 and 2017 which were found to be 0.76, 0.62, 0.71 and 0.86 respectively indicating that SVM outperforms MNDWI in effectively monitoring landform changes. [ABSTRACT FROM AUTHOR]

The Sri Lankan Port City project provides land for urban construction through land reclamation, a large number of dredgers, traffic vessels, and cargo ships are employed during the construction process. Therefore, it is necessary to simulate the wave field during the construction process to evaluate the influence of waves on engineering ships. Based on GFS sea surface wind field data and GEBCO water depth data, the wave numerical models Wave Watch III and SWAN were nested in multiple layers to establish a numerical simulation system suitable for wave field in the Port City area of Sri Lanka. The system was verified by comparing with the measured data. Based on this system, numerical analysis was conducted on the wave field in the Port City construction area at different construction stages. The trend of wave height, period and direction in the whole construction process of typical construction site was obtained. This paper provides an effective method for the numerical simulation of wave fields in nearshore waters, and provides an important reference basis for the reasonable arrangement of engineering ship operation window and the improvement of construction efficiency. [ABSTRACT FROM AUTHOR]

An oscillating buoy (OB) could function simultaneously as a wave energy converter and a breakwater. In this work, a numerical study is conducted to assess the ability of the buoy to perform both aforementioned tasks by quantitatively and qualitatively assessing its hydrodynamic performance. The computational fluid dynamics solver used for the numerical study is ANSYS Fluent, which uses Reynoldsaveraged Navier-Stokes equations and Volume of Fluid method for the design and simulation of the numerical model, which consists of a rectangular OB that floats on the surface of a numerical wave tank. First, a total of six independent studies, namely the time, meshing, damping, overset geometry, flow viscosity, and spatial studies, were conducted for validation purposes. Second, calculation and analysis of the heave and transmission coefficients and vorticity magnitude were conducted to assess the hydrodynamic performance. Results of independent studies show cases with a high degree of accuracy to the experimental model, whereas results for hydrodynamic performance show a generally increasing heave movement of OB and transmission coefficient across the range of wave periods studied. Meanwhile, the vorticity magnitude flow fields show at least two vortices for all wave periods studied, except for the shortest two wave periods. [ABSTRACT FROM AUTHOR]

Stone boulders breakwaters are the most widespread and widely used type of breakwaters. if the foundations of these structures do not have sufficient bearing capacity, large settlements will await the structure. Since the construction of these projects is expensive, and the supply of suitable stone resources are essential for the construction of these projects, a relatively good prediction of the stone materials volume used in the project is important. Therefore, a research project was carried out at Siyadi Port breakwater, (Iran) utilizing geotechnical data and construction observations. The objective was to create a computer model to understand the response of the clay bed to the weight of the rocks. This analysis was done by Lagrangian equations and using FLAC software and led to the selection of characteristic of soil parameters that simulated the subsidence of materials on an elasto-plastic bed. Soil resistance parameters that could not be determined through standard tests were derived through a process of back analysis. The study also investigated the effects of the thickness of the loose layer, variations in sea water levels, and the use of geotextile in the project. A large rise in settling is anticipated as the muddy soil's depth increases. Results also confirms the effectiveness of using geotextiles for settlement management. Moreover, updated characteristics of soil from the previous step in order to comprehend the construction of an entire breakwater section on muddy soil seems crucial. With this method, long-term settlements and the stability of the breakwater section may be reliably predicted. [ABSTRACT FROM AUTHOR]

The safety of pedestrians on a breakwater structure or seawall is significantly influenced by two essential factors: the wave overtopping flow velocity (OFV) and the overtopping layer thickness (OLT). The main issue, however, is that most studies have predominantly focused on impermeable structures rather than composite breakwaters. This study conducted 55 physical experiments to investigate the OFV and OLT on a composite breakwater. The non-intrusive bubble image velocimetry (BIV) technique was employed to measure the OFV and OLT, as well as the plunging distance on the rear side of the structure. Empirical equations with two sets of dimensionless variables, the wave steepness and relative crest freeboard, were proposed as predictors. The results show that these two dimensionless variables perform well for both OFV and OLT estimation. The comparison between the proposed empirical equation and the available empirical equation in the literature is also presented. Finally, the proposed empirical equations were used to estimate the maximum instantaneous wave overtopping discharge and plunging distance. The findings of this research offer insights into the physical mechanisms of wave overtopping, providing an initial exploration into the design of composite breakwaters. [ABSTRACT FROM AUTHOR]

In this paper, the Smoothed Particle Hydrodynamics (SPH) method is used in a C# environment to simulate the interaction between freak waves and bottom-fixed structures by establishing a fluid dynamics model. Paraview software 5.10.1 was used to analyze and visualize the simulation results. In order to simulate wave propagation accurately, the reliability of the model was verified by comparing experimental and simulated data. A two-dimensional numerical wave flume was established based on the SPH method, a conservative Riemann solver was introduced, a repulsive boundary condition was adopted, and a slope was used to eliminate wave reflection. Bottom-fixed structures of different heights and lengths, as well as different wave conditions, were selected to numerically simulate the interaction between freak waves and bottom-fixed structures. The results show that the height of bottom-fixed structures and wave conditions have a significant effect on hindering the propagation of rogue waves, while the length has little effect on the propagation of deformed waves. When the amplitude of the wave remains constant, both the period andthe duration of the deformed wave are longer. This research is of certain significance for the prediction of freak waves in marine engineering and the application and promotion of SPH methods. [ABSTRACT FROM AUTHOR]

Wave propagation, a phenomenon involving the transfer of energy over time, is a significant area of study, particularly with respect to sea waves. Due to their unique geometrical properties and inhomogeneous minimum amplitude, sea waves pose distinct challenges for numerical solutions. This research focuses on the analysis of wave stability against various water velocities and breakwater distances from the coastline. The study employs a hybrid approach, utilizing the Finite Element Method (FEM) to determine the movement of fluid elements through a porous, submerged breakwater. The concept of permeability in breakwaters is integral to this analysis. Permeable breakwaters permit a certain proportion of seawater or wave water to pass through, while absorbing or reflecting the remaining component of the waves. Understanding the permeability of breakwaters can enhance the design effectiveness and efficiency, whilst providing insight into potential impacts on coastal ecosystems. The results of the study demonstrate that the distance of the breakwater from the incoming wave influences both the amplitude and speed of the wave. Specifically, a greater distance between the wave and the breakwater results in a decrease in wave height, thereby increasing the stability of the simulation. For example, the directional and speed components of the movement at [x, y, t] for the first amplitude [20, 2, 15] was found to be 0.12515m, the second amplitude [15, 2, 15] 0.13161m, and the third amplitude [10, 2, 15] 0.13097m. This demonstrates that the breakwater's distance significantly influences wave stability, an important factor to consider in future breakwater design and implementation. [ABSTRACT FROM AUTHOR]

Garis pantai pada umumnya mengalami perubahan posisi dari waktu ke waktu akibat adanya abrasi dan sedimentasi. Perubahan garis pantai dipengaruhi oleh beberapa faktor, salah satunya akibat adanya bangunan pantai. Penelitian ini bertujuan untuk melihat perubahan garis pantai akibat adanya bangunan pantai breakwater di Pulau Pramuka, Kepulauan Seribu. Metode pengolahan dan analisis data dilakukan menggunakan teknologi penginderaan jauh. Dari hasil pengolahan dan analisis data citra satelit Landsat 7 dan 8 dari tahun 2010 sampai tahun 2017 terdapat endapan sedimen atau akresi di pantai Pulau Pramuka akibat adanya bangunan breakwater. Luas endapan sedimen yang terjadi pada tahun 2010 sebesar 7.731 ha, pada tahun 2015 sebesar 7.974 ha, sedangkan pada tahun 2016 sebesar 5.285 ha dan pada tahun 2017 sebesar 5.387 ha. Timbulnya endapan sedimen di pinggiran pantai akibat breakwater ini mengakibatkan terjadinya perubahan garis pantai di sekitar Pulau Pramuka.

A dual-pontoon WEC-breakwater system is proposed to optimise space utilisation and reduce construction costs by integrating wave energy converters (WECs) with breakwaters. Previous parametric studies on the dimensions and layout of WECs have primarily used potential flow theories, often neglecting the viscous effects in wave–pontoon interactions. In this research, I employ a fully nonlinear viscous model, OpenFOAM®, to address these limitations. I examine multiple parameters, including the gap width between the pontoons, the draft, and the structure breadth, to assess their impact on the functional performance of this hybrid system. Furthermore, I discuss the accurate hydrodynamic performance of waves interacting with multiple floating structures and explore how various parameters influence the dual-pontoon WEC-breakwater integrated system’s functionality. I discuss a novel analysis of the effective frequency bandwidth, considering both wave energy conversion efficiency and wave attenuation efficiency, to reflect the overall performance of the integrated system. This paper investigates wave–structure interactions and suggests optimisation strategies for the WEC-breakwater integrated system.

This study numerically analyzes a submerged horizontal plate (SHP) device subjected to both regular and irregular waves. This device can be used either as a breakwater or a wave energy converter (WEC). The WaveMIMO methodology was applied for the numerical generation and wave propagation of the sea state of the Rio Grande coast in southern Brazil. The finite volume method was employed to solve conservation equations for mass, momentum, and volume fraction transport. The volume of fluid model was employed to handle the water-air mixture. The SHP length (Lp) effects were carried out in five cases. Results indicate that relying solely on regular waves in numerical studies is insufficient for accurately determining the real hydrodynamic behavior. The efficiency of the SHP as a breakwater and WEC varied depending on the wave approach. Specifically, the SHP demonstrates its highest breakwater efficiency in reducing wave height at 2.5Lp for regular waves and 3Lp for irregular waves. As a WEC, it achieves its highest axial velocity at 3Lp for regular waves and 2Lp for irregular waves. Since the literature lacks studies on SHP devices under the incidence of realistic irregular waves, this study significantly contributes to the state of the art.

Wave energy conversion holds promise for renewable energy, but challenges like high initial costs hinder commercialization. Integrating wave-energy converters (WECs) into shore-protection structures creates dual-function structures for both electricity generation and coastal protection. Oscillating water columns (OWCs) have been well studied in the past with their simple generation mechanism and their out-of-water power take-off (PTO) system, which can minimize bio-fouling effects and maintenance costs compared to other submerged WECs. In addition, a slotted barrier allows for better circulation behind the breakwater while dissipating incoming wave energy through viscous damping. This study examines the performance of a new design which combines an OWC with a slotted breakwater. Small-scale (1:49) laboratory tests were performed with a piston-type wave generator. The performance is evaluated in terms of wave transmission, wave energy extraction, and wave loading under various wave conditions while focusing on the effects of the porosity of the slotted barrier and tide level changes. Results show that under larger waves, a decreasing wave transmission, increasing power extraction from the OWC, and energy dissipation from the slotted barrier are observed. On the other hand, under increasing wavelengths, wave transmission is observed to be constant; this is important for harbor design, which means that the breakwater is effective under a wider range of wavelengths. Porosity allows for more transmission while inducing less horizontal force on the structure.

This paper aims to use deep learning algorithms to identify and study the stability of breakwater armor blocks. It introduces a posture identification model for fender blocks using a Mask Region-based Convolutional Neural Network (R-CNN), which has been enhanced by considering factors affecting breakwater fender blocks. Furthermore, a wave prediction model for breakwaters is developed by integrating Bidirectional Encoder Representations from Transformers (BERTs) with Bidirectional Long Short-Term Memory (BiLSTM). The performance of these models is evaluated. The results show that the accuracy of the Mask R-CNN and its comparison algorithms initially increases and then decreases with higher Intersection Over Union (IOU) thresholds, peaking at 95.16% accuracy at an IOU threshold of 0.5. The BERT-BiLSTM wave prediction model maintains a loss value around 0.01 and an accuracy of approximately 90.00%. These results suggest that the proposed models offer more accurate stability assessments of breakwater armor blocks. By combining the random forest prediction model with BiLSTM, the wave characteristics and fender posture can be predicted better, offering reliable decision support for breakwater engineering.

In order to meet the needs of the engineering design of the new container terminal breakwater at Ghana忆s Tema Port, a wave cross-section physical model experiment was conducted to study the stability of the breakwater忆s armor and the wave height behind the breakwater. The results show that the original design of the breakwater could not meet the stability requirements, and thus an optimization experiment was carried out on the cross-section. By increasing the height of the top of the breakwater and decreasing the slope of the back slope, the stability of the armor blocks on the back slope could be effectively increased. During the wave profile experiment, oblique incident waves were generalized as normal incident waves, resulting in a conservative experimental result. When it is not possible to carry out a complete physical model of the waves, the effect of oblique incident waves can be considered by reducing the wave height. [ABSTRACT FROM AUTHOR]

In this work, an oscillating water column (OWC) device is considered placed in front of a V-shaped vertical breakwater. The idea conceived, is based on the amplified wave power absorption due to the wave interactions originating from the presence of the breakwater. A theoretical analysis is presented in the realm of linear potential theory, based on the solution of proper diffraction, and radiation problems in the frequency domain, using the eigenfunction expansion method, the method of images, and the multiple scattering approach. Optimum absorption efficiency is examined taking into consideration the characteristics of the power take off (PTO) system and the air compressibility. Numerical results are presented and discussed in terms of the expected power absorption. The effect of the distance between the OWC and the vertical walls, the breakwater's forming angle, and the wave heading angle, is examined to demonstrate the enhanced absorption ability of the device. It is concluded that the device's efficiency is strongly dependent on the position of the OWC in front of the walls, as well as the angle of the wave impact, and should be taken into account when determining the optimum device parameters for maximization of its performance. [ABSTRACT FROM AUTHOR]

The number of operation days of a wharf is an important indicator for the wharf design. Based on the proposed breakwater at the north side of Yangshan Port, in this paper, a wave numerical calculation model, SWAN, is used to establish a wave mathematical model to simulate and calculate the wave elements in the port area, and, according to the analysis of wave frequency obtained at wave observation stations, calculate the number of operation days affected by the waves on the operation of the wharf. According to the calculation results, the breakwater can effectively block the waves in the E, N, NE, and NW directions that have a significant impact on the wharf. The wharf on the west is greatly affected by the waves and has many non- operational days. At the same time, the influence of different design schemes of the breakwater on the operation days of the wharf is also discussed, providing a reference basis for the early design of the breakwater. [ABSTRACT FROM AUTHOR]

This study integrated piezoelectric layers in a flexible membrane to form a piezoelectric membrane. A fluid-filled piezoelectric membrane, which can be used as breakwater and wave energy converter simultaneously, was presented. The mathematical models to describe the interactions of the waves with the piezoelectric membrane were given. The dimensionless parameters to control the behavior of the piezoelectric membrane were obtained. The mixed Eulerian-Lagrangian method was employed to simulate the mathematical models. The simulation code was verified. Based on the simulation results, the effects of dimensionless elastic modulus of the membrane E*, tension of the membrane T0* and the resistance of the load R* on the behavior of the piezoelectric membrane were discussed. As E* is small (E*<0.04) and T0* is not too small (T0* >0.0001), the response of the piezoelectric membrane can be considered as linear. For linear response, the minimum transmission coefficient and maximum output electric power of the piezoelectric membrane can be achieved simultaneously by adjusting T0* and R*. For larger E*, nonlinear behavior of the piezoelectric membrane is observed. At some larger values of E*, working frequency of piezoelectric elements can reach eight times the wave frequency. In these cases, higher output electric power can be achieved for smaller strain of the membrane. [ABSTRACT FROM AUTHOR]