Pub Date : 2026-01-30Epub Date: 2025-10-30DOI: 10.1016/j.coastaleng.2025.104904
Byunguk Kim , Yong Sung Park , Hyoseob Noh , Seungjun Baek
This study presents an improvement of an advanced video-based depth inversion method by introducing a nonlinearity correction to mitigate errors arising from wave shoaling in shallow water. Conventional kinematic depth inversion methods relying on the linear dispersion relation systematically overestimate depth where wave nonlinearity becomes significant. To resolve this, we incorporate a correction factor accounting for wave shoaling and refraction, gradually activated based on incident wave properties and local depths, ensuring adjustments only where nonlinearity significantly affects wave dispersion. Depth estimates are iteratively refined by updating the correction factor using the Newton-Raphson method. The resulting water depth map was validated against photogrammetric bathymetry data with decimeter-level resolution obtained from a field experiment at Byeonsan Beach, South Korea. The results demonstrated that the proposed correction reduced the overall average error by 18.6 %, with a 39.3 % improvement in shallower regions. This marked enhancement confirms that wave nonlinearity, often neglected in previous depth inversion applications, is a critical source of bias in shallow water.
{"title":"Nonlinearity-corrected kinematic depth inversion from UAV imagery in irregular tidal flats: Application to Byeonsan Beach, South Korea","authors":"Byunguk Kim , Yong Sung Park , Hyoseob Noh , Seungjun Baek","doi":"10.1016/j.coastaleng.2025.104904","DOIUrl":"10.1016/j.coastaleng.2025.104904","url":null,"abstract":"<div><div>This study presents an improvement of an advanced video-based depth inversion method by introducing a nonlinearity correction to mitigate errors arising from wave shoaling in shallow water. Conventional kinematic depth inversion methods relying on the linear dispersion relation systematically overestimate depth where wave nonlinearity becomes significant. To resolve this, we incorporate a correction factor <span><math><mrow><mi>ε</mi></mrow></math></span> accounting for wave shoaling and refraction, gradually activated based on incident wave properties and local depths, ensuring adjustments only where nonlinearity significantly affects wave dispersion. Depth estimates are iteratively refined by updating the correction factor using the Newton-Raphson method. The resulting water depth map was validated against photogrammetric bathymetry data with decimeter-level resolution obtained from a field experiment at Byeonsan Beach, South Korea. The results demonstrated that the proposed correction reduced the overall average error by 18.6 %, with a 39.3 % improvement in shallower regions. This marked enhancement confirms that wave nonlinearity, often neglected in previous depth inversion applications, is a critical source of bias in shallow water.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104904"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-11-11DOI: 10.1016/j.coastaleng.2025.104908
Donghui Zhao , Yihao Zheng , Haijiang Liu
Wave period is a crucial factor in determining the complex wave-induced groundwater hydrodynamics, which however has not been systematically investigated. In this study, laboratory experiments were carried out to illustrate the groundwater hydrodynamics under different wave period conditions in a medium-sized sand beach. Detailed pore-pressure data at various elevations and cross-shore positions, together with the shoreline movement, the exit point mitigation, and the free water surface profile, were measured and recorded to specify the spatiotemporal varying characteristics of the groundwater seepage flows and the groundwater table oscillations under different wave periods. Comparing the results among different swash stages reveals that variations in the surface water level, the seepage face, and the groundwater table under different wave periods lead to notable differences in the instantaneous groundwater responses and distinct statistical characteristics of the seepage flow direction over a wave cycle. From a time-averaged perspective, short-period waves induce stronger seepage flows and larger spatial gradients of the total hydraulic head, while long-period waves lead to less pronounced overall groundwater hydrodynamics. The limited migration extension of the exit point under the short wave period results in smaller intra-cycle oscillations of the groundwater table, while a larger groundwater overheight comparing with the relevant long period results. In addition, two types of groundwater table fluctuations are observed for the short wave period case, i.e., the harmonic oscillation caused by the periodic wave swash, and the wave breaking induced groundwater table oscillation. During its inland propagation, the swash-induced oscillation features with rapid magnitude attenuation but no phase lag, whereas the wave-breaking induced oscillation characterizes by the spatially uniform magnitude while a clear phase lag in the capillary truncated zone. Findings from the present study further enhance our understandings on the wave-induced groundwater hydrodynamics.
{"title":"Experimental study of the wave-induced groundwater hydrodynamics under different periods","authors":"Donghui Zhao , Yihao Zheng , Haijiang Liu","doi":"10.1016/j.coastaleng.2025.104908","DOIUrl":"10.1016/j.coastaleng.2025.104908","url":null,"abstract":"<div><div>Wave period is a crucial factor in determining the complex wave-induced groundwater hydrodynamics, which however has not been systematically investigated. In this study, laboratory experiments were carried out to illustrate the groundwater hydrodynamics under different wave period conditions in a medium-sized sand beach. Detailed pore-pressure data at various elevations and cross-shore positions, together with the shoreline movement, the exit point mitigation, and the free water surface profile, were measured and recorded to specify the spatiotemporal varying characteristics of the groundwater seepage flows and the groundwater table oscillations under different wave periods. Comparing the results among different swash stages reveals that variations in the surface water level, the seepage face, and the groundwater table under different wave periods lead to notable differences in the instantaneous groundwater responses and distinct statistical characteristics of the seepage flow direction over a wave cycle. From a time-averaged perspective, short-period waves induce stronger seepage flows and larger spatial gradients of the total hydraulic head, while long-period waves lead to less pronounced overall groundwater hydrodynamics. The limited migration extension of the exit point under the short wave period results in smaller intra-cycle oscillations of the groundwater table, while a larger groundwater overheight comparing with the relevant long period results. In addition, two types of groundwater table fluctuations are observed for the short wave period case, i.e., the harmonic oscillation caused by the periodic wave swash, and the wave breaking induced groundwater table oscillation. During its inland propagation, the swash-induced oscillation features with rapid magnitude attenuation but no phase lag, whereas the wave-breaking induced oscillation characterizes by the spatially uniform magnitude while a clear phase lag in the capillary truncated zone. Findings from the present study further enhance our understandings on the wave-induced groundwater hydrodynamics.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104908"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-11-05DOI: 10.1016/j.coastaleng.2025.104902
Ian Robertson , Alejandro Alvaro , Siddhartha Verma , Benjamin Jones , Joshua Levy , Mert Gokdepe , Zhenhua Huang , Consortium R3D
Understanding the breaking characteristics of waves is important in several nearshore applications such as assessing impacts of submerged engineered structures on wave breaking or computing surf zone energy budgets. Past studies have used images collected by remote sensing to estimate characteristics such as breaking wave height, depth, position, and type (e.g., plunging, spilling, non-breaking). Due to the dynamic nature of breaking waves, breaker classification from a single image may have large uncertainty. For this reason, an approach involving multiple frames is explored. Here, we develop a you only look once – random forest (YOLO-RF) machine learning (ML) model to predict breaker type (plunging or spilling) from GoPro video data shot cross-shore at oncoming waves (face-on). A YOLO model which classifies five wave features (i.e., prebreaking, curling, splashing, whitewash, crumbling) in a set of video frames is coupled to an RF model which takes normalized feature counts over multiple frames as inputs, and outputs a wave-breaking type for each detected wave. The YOLO model detects wave features as separate objects allowing for individual classification of waves in the same frame. The model, trained and validated with data from a large-scale wave-flume experiment, identifies breaker type with 94 % accuracy proving useful for consistent laboratory data. Only a small subset of cases needs to be labeled by hand for training, while the remainder can be labeled by the YOLO-RF model. This open-source approach could be adapted for field settings to aid in understanding, predicting, and modeling wave breaking dynamics in the nearshore environment.
{"title":"Autonomous classification of wave breaker type in a large wave flume","authors":"Ian Robertson , Alejandro Alvaro , Siddhartha Verma , Benjamin Jones , Joshua Levy , Mert Gokdepe , Zhenhua Huang , Consortium R3D","doi":"10.1016/j.coastaleng.2025.104902","DOIUrl":"10.1016/j.coastaleng.2025.104902","url":null,"abstract":"<div><div>Understanding the breaking characteristics of waves is important in several nearshore applications such as assessing impacts of submerged engineered structures on wave breaking or computing surf zone energy budgets. Past studies have used images collected by remote sensing to estimate characteristics such as breaking wave height, depth, position, and type (e.g., plunging, spilling, non-breaking). Due to the dynamic nature of breaking waves, breaker classification from a single image may have large uncertainty. For this reason, an approach involving multiple frames is explored. Here, we develop a you only look once – random forest (YOLO-RF) machine learning (ML) model to predict breaker type (<em>plunging</em> or <em>spilling)</em> from GoPro video data shot cross-shore at oncoming waves (face-on). A YOLO model which classifies five wave features (i.e., prebreaking, curling, splashing, whitewash, crumbling) in a set of video frames is coupled to an RF model which takes normalized feature counts over multiple frames as inputs, and outputs a wave-breaking type for each detected wave. The YOLO model detects wave features as separate objects allowing for individual classification of waves in the same frame. The model, trained and validated with data from a large-scale wave-flume experiment, identifies breaker type with 94 % accuracy proving useful for consistent laboratory data. Only a small subset of cases needs to be labeled by hand for training, while the remainder can be labeled by the YOLO-RF model. This open-source approach could be adapted for field settings to aid in understanding, predicting, and modeling wave breaking dynamics in the nearshore environment.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104902"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-10-31DOI: 10.1016/j.coastaleng.2025.104898
Paul Renaud , Florian Hulin , Alan Tassin , Jean-François Filipot , Nicolas Jacques
Most offshore structures are made of vertical cylinders and may be exposed to breaking waves, which are known to generate impulsive forces that are challenging to estimate. In particular, engineering formulas are often based on an oversimplified representation of the breaking wave, leading to a poor estimate of the load time history. In this study, the wave shape and the fluid kinematics are obtained from a fully nonlinear potential flow solver to reduce the uncertainty on the wave characterisation. The slamming force is then estimated using a semi-analytical water impact model based on Wagner theory and the data from the fully nonlinear simulations. The modelled forces are compared with experimental data on a segmented cylinder impacted by breaking waves of various strengths. The influence of the distance between the cylinder and the breaking point is studied. The model is shown to reproduce accurately the force measurements on the two upper sections impacted by strong plunging breaking waves. The model is compared to other formulations and is shown to improve the estimation of the load time history. For waves of low and mid-breaking strength, the model highly overestimates the force acting on the upper section impacted by the wave crest. The presence of the cylinder in the wave field leads to run-up and diffraction effects that disturb the wave profile. Therefore, accounting for the unperturbed wave kinematics is a conservative approach to evaluate the force acting on the upper section, whereas the evolution of load in time on the lower section is accurately reproduced for all waves.
{"title":"Analysis of slamming loads induced by breaking waves on vertical cylinders using fully nonlinear wave kinematics and semi-analytical load model","authors":"Paul Renaud , Florian Hulin , Alan Tassin , Jean-François Filipot , Nicolas Jacques","doi":"10.1016/j.coastaleng.2025.104898","DOIUrl":"10.1016/j.coastaleng.2025.104898","url":null,"abstract":"<div><div>Most offshore structures are made of vertical cylinders and may be exposed to breaking waves, which are known to generate impulsive forces that are challenging to estimate. In particular, engineering formulas are often based on an oversimplified representation of the breaking wave, leading to a poor estimate of the load time history. In this study, the wave shape and the fluid kinematics are obtained from a fully nonlinear potential flow solver to reduce the uncertainty on the wave characterisation. The slamming force is then estimated using a semi-analytical water impact model based on Wagner theory and the data from the fully nonlinear simulations. The modelled forces are compared with experimental data on a segmented cylinder impacted by breaking waves of various strengths. The influence of the distance between the cylinder and the breaking point is studied. The model is shown to reproduce accurately the force measurements on the two upper sections impacted by strong plunging breaking waves. The model is compared to other formulations and is shown to improve the estimation of the load time history. For waves of low and mid-breaking strength, the model highly overestimates the force acting on the upper section impacted by the wave crest. The presence of the cylinder in the wave field leads to run-up and diffraction effects that disturb the wave profile. Therefore, accounting for the unperturbed wave kinematics is a conservative approach to evaluate the force acting on the upper section, whereas the evolution of load in time on the lower section is accurately reproduced for all waves.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104898"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-10-10DOI: 10.1016/j.coastaleng.2025.104892
Xianghui Dong , Qingxiang Liu , Stefan Zieger , Ian R. Young , Rui Li , Alberto Meucci , Jian Sun , Kejian Wu , Alexander V. Babanin
This study presents a 45-year (1979–2023) high-resolution wave hindcast for the entire Australian coast, conducted using WAVEWATCH III on an unstructured mesh with a resolution ranging from 1 to 15 km. Incorporating the observation-based source term package (i.e., ST6) and the subgrid-scale reef parameterization, the model performs well in simulating widely-used bulk wave parameters. The simulated significant wave height achieves a correlation greater than 0.96 and exhibits only a centimeter-scale bias when compared to both altimeter and buoy observations. The use of BARRAv2 winds provides a clear advantage under extreme conditions, with negligible underestimation below the 99.9th percentile of . The model performs particularly well in the Great Barrier Reef (GBR) region, where the bathymetry is complicated and could not be resolved well by typical km-scale wave models. Unlike previously published hindcasts that excessively overestimated wave energy in the GBR, our results show only a marginal bias of approximately −0.05 m, against the shallow water buoys in this specific region. This better performance can be attributed to the subgrid-scale reef parameterization adopted. Long-term validation results demonstrate the robustness of the model framework, with the hindcast showing good temporal homogeneity and reliability. Building upon these results, this study reveals statistically significant increasing trends in wave heights along most of the Australian coast, with particularly pronounced upward trends in extreme wave heights (90th, 95th, and 99th percentiles) in the GBR. Furthermore, the GBR trends based on our hindcast are much stronger than those estimated from previous hindcasts, and this new finding requires further investigation.
{"title":"A 45-year high-resolution unstructured wave hindcast for the Australian coast: Validation and climatological insights","authors":"Xianghui Dong , Qingxiang Liu , Stefan Zieger , Ian R. Young , Rui Li , Alberto Meucci , Jian Sun , Kejian Wu , Alexander V. Babanin","doi":"10.1016/j.coastaleng.2025.104892","DOIUrl":"10.1016/j.coastaleng.2025.104892","url":null,"abstract":"<div><div>This study presents a 45-year (1979–2023) high-resolution wave hindcast for the entire Australian coast, conducted using WAVEWATCH III on an unstructured mesh with a resolution ranging from 1 to 15 km. Incorporating the observation-based source term package (i.e., ST6) and the subgrid-scale reef parameterization, the model performs well in simulating widely-used bulk wave parameters. The simulated significant wave height <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> achieves a correlation greater than 0.96 and exhibits only a centimeter-scale bias when compared to both altimeter and buoy observations. The use of BARRAv2 winds provides a clear advantage under extreme conditions, with negligible underestimation below the 99.9th percentile of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>. The model performs particularly well in the Great Barrier Reef (GBR) region, where the bathymetry is complicated and could not be resolved well by typical km-scale wave models. Unlike previously published hindcasts that excessively overestimated wave energy in the GBR, our results show only a marginal <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> bias of approximately −0.05 m, against the shallow water buoys in this specific region. This better performance can be attributed to the subgrid-scale reef parameterization adopted. Long-term validation results demonstrate the robustness of the model framework, with the hindcast showing good temporal homogeneity and reliability. Building upon these results, this study reveals statistically significant increasing trends in wave heights along most of the Australian coast, with particularly pronounced upward trends in extreme wave heights (90th, 95th, and 99th percentiles) in the GBR. Furthermore, the GBR <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> trends based on our hindcast are much stronger than those estimated from previous hindcasts, and this new finding requires further investigation.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104892"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-11-05DOI: 10.1016/j.coastaleng.2025.104907
Felipe Teixeira-Duarte , Paulo Rosa-Santos , Francisco Taveira-Pinto
This study presents a multi-objective genetic algorithm (GA) framework for optimizing nearshore wave energy converter (WEC) farm layouts, balancing renewable energy production and coastal protection. Applied to the Ofir–Cávado River mouth in Esposende, Portugal, the framework integrates the SNL-SWAN spectral wave model to simulate wave propagation and energy extraction. Representative sea states are derived through k-means clustering of historical wave data, reducing computational costs while preserving key metocean variability. The GA simultaneously optimizes two metrics: the q-factor (power capture efficiency) and the HRA (reduction in significant wave height in the protected area), combined into a Wave Energy Park Layout Assessment index. Two optimization scenarios are tested: prioritizing coastal protection (maximizing HRA) and minimizing environmental impact (minimizing HRA). The coastal protection layout achieved a 26 % increase in q-factor and a 40 % improvement in HRA compared to a fixed benchmark, while the minimal-impact layout had a 24 % q-factor gain with a 7 % HRA reduction. Results confirm GA's effectiveness in designing WEC farms that enhance energy capture and shoreline resilience. The adaptable framework supports sustainable coastal energy planning and can integrate future wave modeling tools.
{"title":"Optimizing nearshore wave energy Farms: A multi-objective genetic algorithm framework for power capture and coastal protection","authors":"Felipe Teixeira-Duarte , Paulo Rosa-Santos , Francisco Taveira-Pinto","doi":"10.1016/j.coastaleng.2025.104907","DOIUrl":"10.1016/j.coastaleng.2025.104907","url":null,"abstract":"<div><div>This study presents a multi-objective genetic algorithm (GA) framework for optimizing nearshore wave energy converter (WEC) farm layouts, balancing renewable energy production and coastal protection. Applied to the Ofir–Cávado River mouth in Esposende, Portugal, the framework integrates the SNL-SWAN spectral wave model to simulate wave propagation and energy extraction. Representative sea states are derived through k-means clustering of historical wave data, reducing computational costs while preserving key metocean variability. The GA simultaneously optimizes two metrics: the <em>q-factor</em> (power capture efficiency) and the HRA (reduction in significant wave height in the protected area), combined into a Wave Energy Park Layout Assessment index. Two optimization scenarios are tested: prioritizing coastal protection (maximizing HRA) and minimizing environmental impact (minimizing HRA). The coastal protection layout achieved a 26 % increase in <em>q-factor</em> and a 40 % improvement in HRA compared to a fixed benchmark, while the minimal-impact layout had a 24 % <em>q-factor</em> gain with a 7 % HRA reduction. Results confirm GA's effectiveness in designing WEC farms that enhance energy capture and shoreline resilience. The adaptable framework supports sustainable coastal energy planning and can integrate future wave modeling tools.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104907"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-11-04DOI: 10.1016/j.coastaleng.2025.104899
Viktoria Kosmalla , Oliver Lojek , Lukas Ahrenbeck , Björn Mehrtens , Constantin Schweiger , David Schürenkamp , Nils Goseberg
Coastal dunes serve as vital natural defenses against storms, with vegetation playing a key role in sediment stabilization and erosion mitigation. This study examines the effects of planting density, planting strategy, and biomass distribution on dune erosion resistance, using Ammophila arenaria in 1:7 scale flume experiments exposed to wave collision regimes. Tests with whole plants (uncut) and belowground-only biomass (cut) at varying planting densities resulted in erosion volume reductions of up to 31.2 % compared to bare dunes. Intermediate densities with well-developed root systems and buried shoots showed the most consistent reductions, while variability indicated the importance of root development and plant health. Belowground biomass alone provided nearly equivalent resistance compared to whole plants. Vegetation also influenced failure mechanisms, promoting notching and slumping with block detachment and deposition at the dune toe. Time-resolved 3D surface data from laser scanning revealed dynamic erosion patterns, while Structure-from-Motion photogrammetry supported detailed end-state analyses.
{"title":"Vegetation effects on dune erosion under wave collision: Influence of planting density, biomass distribution and arrangement in scaled experiments","authors":"Viktoria Kosmalla , Oliver Lojek , Lukas Ahrenbeck , Björn Mehrtens , Constantin Schweiger , David Schürenkamp , Nils Goseberg","doi":"10.1016/j.coastaleng.2025.104899","DOIUrl":"10.1016/j.coastaleng.2025.104899","url":null,"abstract":"<div><div>Coastal dunes serve as vital natural defenses against storms, with vegetation playing a key role in sediment stabilization and erosion mitigation. This study examines the effects of planting density, planting strategy, and biomass distribution on dune erosion resistance, using <em>Ammophila arenaria</em> in 1:7 scale flume experiments exposed to wave collision regimes. Tests with whole plants (uncut) and belowground-only biomass (cut) at varying planting densities resulted in erosion volume reductions of up to 31.2<!--> <!-->% compared to bare dunes. Intermediate densities with well-developed root systems and buried shoots showed the most consistent reductions, while variability indicated the importance of root development and plant health. Belowground biomass alone provided nearly equivalent resistance compared to whole plants. Vegetation also influenced failure mechanisms, promoting notching and slumping with block detachment and deposition at the dune toe. Time-resolved 3D surface data from laser scanning revealed dynamic erosion patterns, while Structure-from-Motion photogrammetry supported detailed end-state analyses.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104899"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-08-22DOI: 10.1016/j.coastaleng.2025.104867
Zhijie Jiang , Jun Zeng , Jian Qiu , Haijiang Liu
Physical interpretation of the seaward boundary condition (SBC) parameter proposed by Guard and Baldock (2007) in dam-break induced swash models is still unclear in experiments. In this study, a series of dam-break laboratory experiments were conducted to reveal such interpretation of the parameter . Different nondimensional upstream reservoir lengths were applied to examine the relationship between parameters and with respect to the temporal variation characteristics of the local water depth. It is found that time-varying histories of the nondimensional water depth are almost identical among different cases when is the same (irrelevant to the initial water heads). Meanwhile, parameters and play analogous roles in determining the local swash features. Based on the maximum water depth, the rise time of the water depth, and its time ratio at a specified position, the one-on-one and averaged - relationships were established. The - relationship was then validated at other slope positions, confirming its applicability across the swash extension. In addition, the one-on-one - relationship presents better agreement between model and experiment than the averaged - relationship. These findings help to clarify the physical interpretation of the SBC parameter with the actual swash hydrodynamic conditions.
{"title":"Experimental interpretation of the seaward boundary condition parameter in dam-break induced swash models","authors":"Zhijie Jiang , Jun Zeng , Jian Qiu , Haijiang Liu","doi":"10.1016/j.coastaleng.2025.104867","DOIUrl":"10.1016/j.coastaleng.2025.104867","url":null,"abstract":"<div><div>Physical interpretation of the seaward boundary condition (SBC) parameter <span><math><mrow><mi>k</mi></mrow></math></span> proposed by Guard and Baldock (2007) in dam-break induced swash models is still unclear in experiments. In this study, a series of dam-break laboratory experiments were conducted to reveal such interpretation of the parameter <span><math><mrow><mi>k</mi></mrow></math></span>. Different nondimensional upstream reservoir lengths <span><math><mrow><mi>L</mi></mrow></math></span> were applied to examine the relationship between parameters <span><math><mrow><mi>L</mi></mrow></math></span> and <span><math><mrow><mi>k</mi></mrow></math></span> with respect to the temporal variation characteristics of the local water depth. It is found that time-varying histories of the nondimensional water depth are almost identical among different cases when <span><math><mrow><mi>L</mi></mrow></math></span> is the same (irrelevant to the initial water heads). Meanwhile, parameters <span><math><mrow><mi>L</mi></mrow></math></span> and <span><math><mrow><mi>k</mi></mrow></math></span> play analogous roles in determining the local swash features. Based on the maximum water depth, the rise time of the water depth, and its time ratio at a specified position, the one-on-one and averaged <span><math><mrow><mi>L</mi></mrow></math></span>-<span><math><mrow><mi>k</mi></mrow></math></span> relationships were established. The <span><math><mrow><mi>L</mi></mrow></math></span>-<span><math><mrow><mi>k</mi></mrow></math></span> relationship was then validated at other slope positions, confirming its applicability across the swash extension. In addition, the one-on-one <span><math><mrow><mi>L</mi></mrow></math></span>-<span><math><mrow><mi>k</mi></mrow></math></span> relationship presents better agreement between model and experiment than the averaged <span><math><mrow><mi>L</mi></mrow></math></span>-<span><math><mrow><mi>k</mi></mrow></math></span> relationship. These findings help to clarify the physical interpretation of the SBC parameter with the actual swash hydrodynamic conditions.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104867"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-10-14DOI: 10.1016/j.coastaleng.2025.104896
Chen Peng , Dezhi Ning , Feng Zhou
Coastal communities face the challenge of mitigating wave-induced hazards while promoting the utilization of renewable wave energy for sustainable development. This study proposes a novel Nested Dual-chamber Oscillating Water Column (ND-OWC) breakwater, designed to enhance power stability while maintaining effective wave attenuation for sustainable coastal defense. The structure integrates a bottom-mounted leeward inlet OWC as the inner chamber and a suspended semi-annular OWC as the outer chamber, forming modular units that are arranged perpendicular to the wave propagation direction to function as a multifunctional breakwater. A comprehensive Computational Fluid Dynamics (CFD) study was conducted to evaluate the hydrodynamic performance of the ND-OWC at both unit and array scales. Results indicate that in the ND-OWC unit, the inner chamber enhances oscillations in the outer chamber, leading to a synergistic increase in energy capture by up to 48.25 %. Moreover, the staggered power contributions from the two chambers reduce power fluctuation by up to 75.61 %, supporting stable power output. Units within the array retain energy capture performance comparable to that of a single unit, while the array configuration ensures effective wave attenuation, with transmission coefficients below 0.60 for 50 % of tested cases. Tightly spaced arrays offer superior wave attenuation but exhibit reduced power stability. Compared with other bottom-mounted OWC array configurations, the present design provides mid-range energy capture while consistently achieving superior wave attenuation and power stability. These findings demonstrate the potential of the ND-OWC system as a viable solution for sustainable coastal protection and renewable energy utilization.
{"title":"Hydrodynamic performance of nested dual-chamber OWC breakwaters for enhanced power stability and wave attenuation","authors":"Chen Peng , Dezhi Ning , Feng Zhou","doi":"10.1016/j.coastaleng.2025.104896","DOIUrl":"10.1016/j.coastaleng.2025.104896","url":null,"abstract":"<div><div>Coastal communities face the challenge of mitigating wave-induced hazards while promoting the utilization of renewable wave energy for sustainable development. This study proposes a novel Nested Dual-chamber Oscillating Water Column (ND-OWC) breakwater, designed to enhance power stability while maintaining effective wave attenuation for sustainable coastal defense. The structure integrates a bottom-mounted leeward inlet OWC as the inner chamber and a suspended semi-annular OWC as the outer chamber, forming modular units that are arranged perpendicular to the wave propagation direction to function as a multifunctional breakwater. A comprehensive Computational Fluid Dynamics (CFD) study was conducted to evaluate the hydrodynamic performance of the ND-OWC at both unit and array scales. Results indicate that in the ND-OWC unit, the inner chamber enhances oscillations in the outer chamber, leading to a synergistic increase in energy capture by up to 48.25 %. Moreover, the staggered power contributions from the two chambers reduce power fluctuation by up to 75.61 %, supporting stable power output. Units within the array retain energy capture performance comparable to that of a single unit, while the array configuration ensures effective wave attenuation, with transmission coefficients below 0.60 for 50 % of tested cases. Tightly spaced arrays offer superior wave attenuation but exhibit reduced power stability. Compared with other bottom-mounted OWC array configurations, the present design provides mid-range energy capture while consistently achieving superior wave attenuation and power stability. These findings demonstrate the potential of the ND-OWC system as a viable solution for sustainable coastal protection and renewable energy utilization.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104896"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30Epub Date: 2025-09-08DOI: 10.1016/j.coastaleng.2025.104875
J.R.M. Muller , B.W. Borsje , J.J. van der Werf , D. Dermentzoglou , B. Hofland , A. Antonini , S.J.M.H. Hulscher
Saltmarshes are a promising nature-based alternative for conventional flood protection. However, saltmarshes can erode under storm conditions, whereby the seaward edge of the saltmarsh often forms a vertical cliff. Despite its importance, the effect of storm conditions on erosion at the saltmarsh cliff remains understudied, especially when waves traverse over a cliff. This research investigates the complex flow patterns around a saltmarsh cliff non-intrusively using Particle Image Velocimetry (PIV) conducted through a series of scaled monochromatic wave flume experiments. We adopted realistic foreshore configurations (e.g. cliff heights) and hydraulic loading conditions from the Dutch Wadden Sea. Results show two local near-bed velocity maxima on top of the saltmarsh, created during different wave phases by water depth contraction, wave transmission and interaction between flow and vortices that are shed from the cliff. Under the wave crest, high onshore-directed near-bed velocities were measured at approximately 2.5–4 times the cliff height onshore from the cliff. Under the wave trough, high offshore-directed velocities were found at the marsh edge. Both onshore- and offshore-directed velocities increase with increasing cliff height, larger wave height or lower water depth. Vegetation on top of the marsh reduces both the incoming and outgoing velocities in front of the cliff. Increasing the cliff height resulted in a greater reduction in velocities by the vegetation. These results demonstrate how local near-bed velocity maxima and location are influenced by the presence of a cliff and the interaction with vegetation on top of the saltmarsh. This research highlights the vulnerability of the cliff even during inundation of the cliff and will help to implement saltmarshes as nature-based solutions for flood defence.
{"title":"Wave-driven hydrodynamics around a saltmarsh cliff under storm conditions: the role of cliff height and vegetation","authors":"J.R.M. Muller , B.W. Borsje , J.J. van der Werf , D. Dermentzoglou , B. Hofland , A. Antonini , S.J.M.H. Hulscher","doi":"10.1016/j.coastaleng.2025.104875","DOIUrl":"10.1016/j.coastaleng.2025.104875","url":null,"abstract":"<div><div>Saltmarshes are a promising nature-based alternative for conventional flood protection. However, saltmarshes can erode under storm conditions, whereby the seaward edge of the saltmarsh often forms a vertical cliff. Despite its importance, the effect of storm conditions on erosion at the saltmarsh cliff remains understudied, especially when waves traverse over a cliff. This research investigates the complex flow patterns around a saltmarsh cliff non-intrusively using Particle Image Velocimetry (PIV) conducted through a series of scaled monochromatic wave flume experiments. We adopted realistic foreshore configurations (e.g. cliff heights) and hydraulic loading conditions from the Dutch Wadden Sea. Results show two local near-bed velocity maxima on top of the saltmarsh, created during different wave phases by water depth contraction, wave transmission and interaction between flow and vortices that are shed from the cliff. Under the wave crest, high onshore-directed near-bed velocities were measured at approximately 2.5–4 times the cliff height onshore from the cliff. Under the wave trough, high offshore-directed velocities were found at the marsh edge. Both onshore- and offshore-directed velocities increase with increasing cliff height, larger wave height or lower water depth. Vegetation on top of the marsh reduces both the incoming and outgoing velocities in front of the cliff. Increasing the cliff height resulted in a greater reduction in velocities by the vegetation. These results demonstrate how local near-bed velocity maxima and location are influenced by the presence of a cliff and the interaction with vegetation on top of the saltmarsh. This research highlights the vulnerability of the cliff even during inundation of the cliff and will help to implement saltmarshes as nature-based solutions for flood defence.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104875"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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