Search Results (422)

Ras El-Bar, a premier historic coastal resort on Egypt’s Nile Delta, has experienced a marked increase in drowning incidents in recent years, despite the presence of extensive coastal protection structures. While these measures, particularly detached breakwaters (DBWs), groins, and port jetties, were originally implemented to mitigate shoreline erosion, their influence on nearshore hydrodynamics and swimmer safety remains insufficiently understood. In this context, the present study integrates high-resolution bathymetric data, remote sensing observations, and coupled numerical modeling (CMS-Wave and CMS-Flow) to examine how these interventions have altered wave–current interactions. The results indicate that the modified coastal setting produces distinct flow regimes, ranging from weak offshore currents (<0.1 m/s) to moderate rip currents (≈0.25 m/s) within DBW shadow zones, and locally intensified flows exceeding 0.7 m/s in shallow nearshore areas. These conditions facilitate the development of vortices and persistent rip currents, particularly within inter-DBW embayments. A simulation-based swimming risk map was developed by integrating water depth and simulated current characteristics, classifying the coastline into safe, moderate-risk, and high-risk zones. High-risk zones, concentrated within inter-DBW embayments at depths exceeding 2 m, show broad spatial agreement with available drowning and rescue incident records, subject to the limitations of the informal dataset, while the shallow accretional shadow zones landward of the DBWs exhibit comparatively lower hydrodynamic energy and safer conditions. Overall, the study demonstrates that coastal protection structures, although effective in controlling erosion, may unintentionally increase human risk when safety considerations are not incorporated into their design and management. Accordingly, a set of integrated, sustainability-oriented measures is proposed, including enhanced real-time monitoring, regulated beach access, adaptive sand nourishment, and targeted public awareness, with the aim of achieving a more balanced and resilient approach to coastal zone management. Full article

A hybrid system combining wave energy converters (WECs) and a floating breakwater presents significant potential for developing commercial-scale wave power operations. The assessment of the hydrodynamic characteristics of a WEC array–floating breakwater system under irregular waves remains in the early stages and requires further investigation. Based on the linear potential theory, a time-domain numerical model is established to evaluate the performance of a hybrid WEC array–floating breakwater system in a target sea area. The interaction between the WECs and the floating breakwater is analyzed. Results show that for the hybrid system with a triangular-baffle-type WEC array under irregular waves, the annual average wave power is 1.16 MW and the annual energy production is 10.16 × 10³ MW·h, representing a 241.2% improvement compared with that of the isolated WEC array. The standard deviations of the mooring forces for the hybrid system with the triangular-baffle-type WEC array are reduced by 13.8% in the surge direction and 26.9% in the pitch direction, while increasing by 90.0% in the heave direction. Similar conclusions are obtained for the motion of the floating breakwater. The findings and data reported in this study provide guidance for the engineering application of a hybrid WEC array–floating breakwater system. Full article

Following successful applications in inland water bodies, floating photovoltaics (FPV) developers are now targeting offshore sites. This advancement requires numerical tools that can quantify the hydrodynamic performance of large-scale FPV farms. The existing wave-diffraction solver DIFFRAC was extended to simulate the response of a large number of interconnected floating objects on a supercomputer. The applicability is demonstrated by simulating a 2 MWp offshore solar farm, consisting of 3660 FPV modules moored inside a protective ring of 32 interconnected floating breakwaters (FBWs). The FPV motions and loads on FPV connectors in regular and irregular waves are compared to a reference case without FBW protection. Results show an average reduction in axial FPV connector loads in the setup with FBW ring, but local load enhancements occur due to dynamic amplifications of horizontal FPV module motions. Vertical loads and overturning moments onto FPV connectors are globally reduced by up to 50% in steep irregular seas but are locally enhanced due to standing waves that develop inside the ring. The insights of the hydrodynamic behaviour lead to recommendations for improving the farm configuration to further reduce fatigue and survival loads onto FPV modules and connectors. Full article

This study investigates the extreme wave event that caused damage to the main breakwater at Chancay Port, Peru, on 24 August 2025 (the 824 event), through high-resolution nested numerical wave simulations. The research reveals the underlying mechanisms and causation of the damage. Results indicate that the extreme waves originated from a powerful storm in the Southern Pacific’s Roaring Forties around 20 August. The storm generated long-period swell that propagated to Chancay Port, resulting in significant wave heights of 4.2–4.4 m offshore, exceeding the 475-year return period design standard and ranking as the most severe wave event in the past 30 years. Localized modeling further demonstrates that the swells induced nonlinear transformations in front of the breakwater, with wave heights reaching up to 7 m along the structure and generating complex standing waves near the bend. Comprehensive analysis concludes that the damage was caused by the combined effects of this rare extreme remote swell and localized hydrodynamic interactions with the breakwater. Full article

Vortex-induced energy dissipation is critical, yet its influence is frequently neglected in potential-flow analysis of wave interaction with thin-walled structures. This study revisits the parametrization of vortex-induced energy dissipation in potential-flow analysis, particularly for wave interaction with vertical, surface-piercing plates. The parametrization is derived by conceptually appending a short perforated region to the vortex-shedding edge of the plate. The underlying physical principle relies on the similarity between vortex shedding from a sharp edge and from an orifice. Two parameters are identified as important: the length of the perforated region and the quadratic loss coefficient associated with the pressure change. For practical applications, the value of the quadratic loss coefficient that is invariant of wave conditions is recommended for a given optimal length of the perforated region. The parametrization is validated using published results for a single plate, and its robustness is further demonstrated through applications involving two surface-piercing vertical plates with varying spacings. The findings of this study can find applications in using potential-flow theory to model plate-type wave breakwaters and wave interaction with thin-walled oscillating water column devices. Full article

The application of artificial intelligence (AI) models in maritime and coastal engineering has gained increasing relevance, demonstrating performance comparable to traditional approaches in wave climate analysis and propagation. However, their use in climate change impact and adaptation studies remains limited, particularly for the design and upgrading of coastal protection structures. To address this gap, this study focuses on the development of an AI-based framework to support the adaptation of breakwaters to future climate conditions. A hybrid approach combining artificial neural networks (ANNs) and genetic algorithms (GAs) was implemented, with two feedforward neural networks-based models developed and applied to different sections of the north breakwater of the Port of Valencia, specifically a vertical section and a compound breakwater. The results indicate that, under future climate scenarios (2050), increases of up to 1.2 m in crest elevation, together with reinforcement of the armor layer, are required to ensure adequate structural performance. The analysis also highlights the critical role of extreme events, as approximately 60% of the model errors were concentrated in the upper 90th percentile of wave conditions. Overall, the proposed hybrid ANN-GA framework demonstrated very strong performance, achieving computational efficiencies 30 to 40 times greater than ANN-only models in terms of computational time. These findings underscore the necessity of adapting coastal structures to climate change and confirm the potential of AI-based models as effective tools for climate-resilient coastal engineering, while emphasizing the importance of accurately representing extreme wave conditions. Full article

Harbour sedimentation represents a major challenge to the environmental sustainability and operational efficiency of coastal infrastructure, as frequent dredging activities increase maintenance costs, ecological disturbance, and carbon emissions. Conventional physical and numerical sediment transport models, while widely applied, are computationally intensive and often unsuitable for early-stage, sustainability-oriented design optimisation. To address these limitations, this study proposes a hybrid artificial intelligence-based optimisation framework integrating Artificial Neural Networks (ANNs), Genetic Algorithms (GAs), and Particle Swarm Optimisation (PSO) for sustainable breakwater and harbour layout design. Hydrodynamic simulations using the Coastal Modelling System (CMS) were conducted to generate a comprehensive dataset describing sediment transport behaviour under varying geometric and structural configurations. An ANN surrogate model was trained to capture nonlinear relationships between breakwater parameters and accumulated sedimentation volume, while GA-based global optimisation and PSO-based validation and local refinement were employed to identify optimal design solutions. Comparative assessment demonstrated consistent convergence of ANN–GA and ANN–PSO solutions within the same design region, with a maximum deviation of 8.46% between design variables and a sedimentation difference of 2.4%. The hybrid ANN–GA–PSO framework achieved the lowest predicted sedimentation volume, representing an improvement of approximately 2.3% relative to the ANN–GA baseline. The proposed framework supports Integrated Coastal Structures Management (ICSM) by enabling proactive, design-stage reduction in long-term sediment accumulation and dredging requirements, offering a scalable pathway toward sustainable and digital-twin-enabled harbour planning. Full article

Resonant Wave Energy Converter 1 (REWEC1) is a submerged caisson breakwater integrating a device designed to absorb incoming wave energy. Although the wave energy-extraction performance of this system and its hydraulic characteristics have been extensively investigated, its potential role in reducing coastal inundation, as an alternative to traditional rubble-mound breakwaters, has not yet been examined. In this context, the present study analyzes the mitigation effects on coastal flooding induced by the installation of REWEC1 barriers. The analysis focuses on the coast of Cetraro, located along the Tyrrhenian Sea in the province of Cosenza (Calabria, Southern Italy). The effectiveness of REWEC1 farms in reducing coastal flooding was assessed by considering fixed-air and no-air operation modes, as well as different spatial configurations. The input wave conditions were propagated in the nearshore using the SWAN model to simulate wave–structure interactions, while the XBeach model was employed to investigate coastal inundation processes based on the wave field behind the caissons, also accounting for Sea Level Rise (SLR). The results were evaluated in terms of maximum flooded areas and water penetration lengths along the emerged coast, as well as wave run-up and set-up along selected transects. To assess the robustness of the results, a sensitivity analysis was carried out by varying the transmission coefficients of the REWEC1 units within a plausible uncertainty range, and the corresponding variability in flooding indicators was quantified. The numerical results indicate a progressive reduction in these hydrodynamic response indicators as the spacing between adjacent REWEC1 devices decreases, and show that the relative mitigation performance of REWEC1 remains consistent when accounting for uncertainties in wave–structure interaction parameters. Further analyses were conducted to compare the effectiveness of REWEC1 farms with that of conventional rubble-mound breakwaters in reducing coastal flooding. Full article

According to CIGRE, the usual arrangement of electrodes in a shoreline electrode station for HVDC interconnections is straight with the following form: forming straight frames with the electrodes at equal distances and placing the frames parallel to the longitudinal axis of the breakwater, successively at fixed distances between them. In a previous paper by the authors, 10 alternative configurations of placement of such straight frames were examined to determine which placements mainly affect the near-field results. In particular, radial or circumferential arrangements of the straight frames on a central base in the open sea improve the overall field results, such as the absolute potential and electrode station resistance to remote earth, satisfying the requirements of the maximum electric field strength. In this paper, the nonlinear configuration of the frames will be studied from an electric field perspective at the level of a preliminary study forming innovative configurations in order to check their suitability with respect to the relevant requirements of the CIGRE guidelines B4.61/2017. These arrangements, located in electrode stations, are evaluated and compared with the older configurations for two cases, those of Korakia in Crete and Stachtoroi in Aegina, Attica, for the HVDC Crete-mainland Greece interconnection of 1 GW, ±500 kV. Full article

Under the combined pressures of natural variability and human activities, the area of tidal flats has been gradually decreasing, with most muddy coasts experiencing varying degrees of erosion. The central coast of Jiangsu Province, a world-renowned region for extensive tidal flats, has witnessed intensifying erosion of its muddy coasts in recent years. To mitigate further coastal erosion, an ecological submerged breakwater (ESB) was constructed in the intertidal zone north of the Sheyang River estuary to reduce wave impact on the shoreline. This study evaluates the wave attenuation performance of the ESB based on wave observations conducted at stations deployed on the seaward and landward sides of the structure in May 2025. Results indicate that the breakwater effectively reduces wave height, but its performance exhibits significant dynamic characteristics. During the observation period, the maximum attenuation rate for significant wave height (H₁/₃) reached 76.3%, with an average rate of 33.8%. Wave dissipation efficiency was closely related to sea state: under calm conditions (H₁/₃ < 0.4 m), the average attenuation rate was only 18.4%, whereas under severe sea states (H₁/₃ ≥ 0.4 m), it increased markedly to 57.6%. The wave transmission coefficients (K_t) span a wide range from 0.20 to 0.99, indicating a significant dynamic variability in the wave attenuation performance of the ESB. The performance of the ESB was primarily controlled by two key factors: incident wave height and submergence depth of the structure. Compared to “zonated” natural ecosystems such as oyster reefs, coral reefs, salt marshes, and mangroves, the ESB, as a “linear” engineered structure, achieves comparable wave attenuation within a limited spatial footprint. A promising future strategy involves using the ESB as a frontline defense, integrated with landward ecological restoration measures like salt marsh rehabilitation, to establish a hybrid “grey-green” coastal protection system that synergistically enhances both coastal resilience and ecological function. This study provides a scientific basis for the design and performance evaluation of ecological engineering solutions for protecting eroding muddy coasts. Full article

Breakwater-integrated caisson-type overtopping wave energy converters (OWECs) can retrofit port infrastructure with energy recovery, and their performance is strongly influenced by submerged-ramp geometry that governs underwater wave-particle motion, reflection, recirculation, and localized breaking. This study establishes a depth-selection framework based on the cumulative distribution of wave-induced kinetic energy from linear wave theory and applies weakly compressible smoothed particle hydrodynamics (WCSPH) simulations using DualSPHysics under regular waves to quantify how hydraulic efficiency responds to ramp slope and installation depth for single-slope designs. Guided by these trends, a segmented multi-angle ramp is proposed to preserve the upper-slope function required for overtopping while reducing submerged volume and foundation demand. Performance is assessed by combining hydraulic efficiency with construction-quantity-based economy indices. Results show that deeper ramps generally enhance efficiency but with diminishing returns, and that the preferred slope depends on the installation depth. In suitable depth ranges, segmented ramps provide a practical compromise between material savings and retained performance. The proposed procedure supports early-stage geometry screening and robust depth-range selection across site conditions. Full article

The Damietta–Port Said coast, Nile Delta, has experienced extreme morphological change over the past four decades due to sediment reduction due to Aswan High Dam and continued anthropogenic pressures. Using multi-temporal Landsat (1985–2025) and high-resolution RapidEye and PlanetScope imagery with 50 m-spaced transects, the study documents major shoreline shifts: the Damietta sand spit retreated by >1 km at its proximal apex while its distal tip advanced by ≈3.1 km southeastward under persistent longshore drift. Sectoral analyses reveal typical structure-induced patterns of updrift accretion (+180 to +210 m) and downdrift erosion (−50 to −330 m). To improve predictive capability beyond linear DSAS extrapolation, Nonlinear Autoregressive Exogenous (NARX) and Bidirectional Long Short-Term Memory (BiLSTM) neural networks were applied to forecast the 2050 shoreline. BiLSTM demonstrated superior stability, capturing nonlinear sediment transport patterns where NARX produced unstable over-predictions. Furthermore, coupled wave–flow modeling validates a sustainable management strategy employing successive short groins (45–50 m length, 150 m spacing). Simulations indicate that this configuration reduces longshore current velocities by 40–60% and suppresses rip-current eddies, offering a sediment-compatible alternative to conventional breakwaters and seawalls. This integrated remote sensing, hydrodynamic, and AI-based framework provides a robust scientific basis for adaptive, sediment-compatible shoreline management, supporting the long-term resilience of one of Egypt’s most vulnerable deltaic coasts under accelerating climatic and anthropogenic pressures. Full article

Designing armor units that can withstand harsh marine environments while remaining cost-effective is a central challenge in modern breakwater engineering. This study introduces a newly designed artificial armor unit and evaluates its performance in comparison with established alternatives such as the accropode, core-loc, and conventional rock armor. The findings reveal that the new unit achieves a lower packing density, reducing the number of units required and thereby improving overall cost-effectiveness. Armor layers formed from the newly designed unit exhibited higher porosity than accropode but lower than core-loc, effectively avoiding the slender geometries that compromise durability. Structural analysis using STAAD.Pro confirmed that the new unit developed lower tensile stresses, with reductions of 15% compared to accropode and 35% compared to core-loc under flexure, torsion, and combined loading, demonstrating superior integrity. Hydraulic stability tests showed that the randomly placed newly designed units resisted failure at a stability number (N_s) of 1.4, lowering run-up by 50% and overtopping by 59%, while the uniformly placed newly designed units reached 1.5 without failure, with run-up and overtopping reductions of 30% and 37%, respectively. Collectively, these outcomes highlight the clear hydraulic and structural advantages of the new design over conventional systems, establishing it as a stronger and more resilient solution for breakwater protection. Full article

This study analyzes the hydrodynamic performance of a V-type wave dissipation system and amphibious landing equipment under different combined fields using the Reynolds-averaged Navier–Stokes (RANS) method. A three-dimensional numerical wave tank is established to simulate regular waves and validate the performance of an airbag-type floating breakwater. This study evaluates the optimal hydrodynamic performance of a V-type wave dissipation system under various configurations in a wave-only field and subsequently compares the efficacy of the better-performing system across multiple environmental conditions. The results show that the V-type wave dissipation system in the configurations of 30° and 45° angles is more favorable for the flow field and the amphibious landing equipment behind it. Compared to the wave-only condition, the time histories of wave heights under both wave-current and wind-wave conditions present an obvious phase advancement. In the wave-current field, a following current reduces the wave height and shortens the wave period. Conversely, in the wind-wave field, a following wind velocity leads to a certain increase in wave height while exerting minimal impact on the wave period. Compared to the wave-only condition, the peak and trough values of the wave height monitoring points in the combined wind-wave-current field show an increasing trend, with a significant increase in resistance and a shorter resistance period for the amphibious landing equipment behind the V-type wave dissipation system. This study shows that the selected V-type wave dissipation system proves to be more effective in wave-only and wave-current conditions, providing valuable references for the engineering application of this system. Full article

To address the lack of efficient flexible protection measures for ocean engineering equipment operating in complex coupled wind–wave–current environments, this study develops a coupled “flexible wave-dissipating system” numerical model based on a validated three-dimensional numerical wave tank. The model is used to investigate, under both regular and irregular wave conditions, the influence of different wind and current incidence angles and the presence or absence of the breakwater on wave propagation and hydrodynamic responses. By comparing the significant wave height, transmission coefficient and wave dissipation efficiency in the sheltered region along with the drag force and free-surface pressure, the wave-attenuation and load-reduction performance of the flexible breakwater is quantitatively evaluated. The results demonstrate that deploying a flexible breakwater can significantly attenuate wave energy in the sheltered region, enhance wave dissipation efficiency, and reduce the transmission coefficient, thereby concurrently decreasing both the drag force and free-surface pressure. Under both wind and current conditions, the maximum loads occur at 0° head-on incidence. However, under 30° oblique wind–wave action, the flexible breakwater yields the most pronounced increase in dissipation efficiency compared to the case without a breakwater. A stable correlation is observed between dissipation efficiency and hydrodynamic loads, which can serve as a unified evaluation metric for assessing the protective performance of flexible breakwaters in ocean engineering applications. Full article