Coastal EngineeringPub Date : 2025-05-31DOI: 10.1016/j.coastaleng.2025.104787
Johnathan Woodruff , J.C. Dietrich , Damrongsak Wirasaet , Andrew B. Kennedy , Diogo Bolster , Richard A. Luettich
{"title":"Resolution sensitivities for subgrid modeling of coastal flooding","authors":"Johnathan Woodruff , J.C. Dietrich , Damrongsak Wirasaet , Andrew B. Kennedy , Diogo Bolster , Richard A. Luettich","doi":"10.1016/j.coastaleng.2025.104787","DOIUrl":"10.1016/j.coastaleng.2025.104787","url":null,"abstract":"<div><div>Flooding due to storm surge can propagate through coastal regions to threaten the built and natural environments. This propagation is controlled by geographic features of varying scales, from the largest oceans to the smallest marsh channels and sandy dunes. Numerical models to predict coastal flooding have been improved via the use of subgrid corrections, which use information about the smallest-scale flow controls to provide corrections to coarser scale grids. Although previous studies have demonstrated the benefits of subgrid models, especially how coarser models can be more efficient without a trade-off in accuracy, this study systematically investigates subgrid corrections in storm surge models across large domains. Here, we apply the widely used ADVanced CIRCulation (ADCIRC) storm surge model with revised subgrid corrections to develop guidance for resolution of coastal regions. Recent hurricanes in the South Atlantic Bight are simulated with five models, each with varying resolution of coastal islands, estuaries, rivers, and floodplains. Model performance is quantified via comparisons with observed data and high-resolution simulations. Clear degradation is observed in the subgrid model performance as minimum mesh resolution becomes coarser than the width of channels conveying flow or the barrier islands blocking flow. Therefore, subgrid model mesh resolution should account for spatial scales of local flow pathways and barrier islands to maintain proper model mass and momentum transfer. However, with subgrid modeling this can be done at much coarser (and thus computationally faster) resolutions than with conventional models.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104787"},"PeriodicalIF":4.2,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205289","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}
Coastal EngineeringPub Date : 2025-05-30DOI: 10.1016/j.coastaleng.2025.104785
Sarah Krogh Iversen, Mads Røge Eldrup, Thomas Lykke Andersen, Peter Frigaard
{"title":"The NL-SORS method for separation of nonlinear multidirectional waves into incident and reflected wave trains","authors":"Sarah Krogh Iversen, Mads Røge Eldrup, Thomas Lykke Andersen, Peter Frigaard","doi":"10.1016/j.coastaleng.2025.104785","DOIUrl":"10.1016/j.coastaleng.2025.104785","url":null,"abstract":"<div><div>Physical model tests are often conducted during the design process of coastal structures. The wave climate in such tests often include short-crested nonlinear waves. The structural response is related to the incident waves measured in front of the structure. Existing methods for separation of incident and reflected short-crested waves are based on linear wave theory. For analysis of nonlinear waves, the existing methods are limited to separation of nonlinear long-crested waves. For short-crested waves, the only options so far has been to use estimates without the structure in place. The present paper thus presents a novel method for directional analysis of nonlinear short-crested waves: Non-Linear Single-summation Oblique Reflection Separation (NL-SORS). The method is validated on numerical model data, as for such data, the target is well defined as simulations may be performed with fully absorbing boundaries. Second- and third-order wave theory is used to demonstrate that small errors on the celerity of nonlinear components in the mathematical model of the surface elevation can be obtained if a double narrow-banded directional spectrum is assumed, i.e. the primary frequency and the directional spreading function must be narrow banded. As the increasing nonlinearity of the waves often arise from waves shoaling on a sloping foreshore, the directional spreading of the waves will decrease due to refraction, and a broad directional spreading function will thus not be experienced in highly nonlinear conditions. The new NL-SORS method is shown to successfully decompose nonlinear short-crested wave fields and estimate the directional spectrum hereof.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104785"},"PeriodicalIF":4.2,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221946","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}
Coastal EngineeringPub Date : 2025-05-26DOI: 10.1016/j.coastaleng.2025.104776
Jochem J. Caspers , Paulina E. Kindermann , Guus W.F. Rongen , Chris P.M. Geerse
{"title":"Storm surge hydrographs and characteristics along the Dutch coast. An analysis from simulation data","authors":"Jochem J. Caspers , Paulina E. Kindermann , Guus W.F. Rongen , Chris P.M. Geerse","doi":"10.1016/j.coastaleng.2025.104776","DOIUrl":"10.1016/j.coastaleng.2025.104776","url":null,"abstract":"<div><div>This study analyzes storm characteristics and surge hydrographs corresponding to extreme storms in the Dutch coastal area, using a large dataset from simulated time series. A total of 8,000 storm events were selected for four study locations, allowing for a comprehensive investigation of various storm characteristics. Findings reveal that the offset between maximum surge and astronomical high tide typically exhibits three predominant values. A new percentile method for averaging storm surge hydrographs was employed, effectively preserving a realistic shape of the storm surge hydrograph and accurately reflecting durations. Comparing the averaged storm surge hydrographs for different magnitudes of the surge peak shows that it is possible to scale the averaged storm surge hydrograph to any peak value, as long as storms are first clustered based on location, tidal offset, and exceedance duration, since these characteristics substantially impact the shape of storm surge hydrographs. Comparisons with current design guidelines show that prescribed storm surge hydrographs often underestimate durations on the flanks of storm events, with variations in peak characteristics depending on location. The insights gained in this study, can be used to improve the representation of hydraulic loads in flood defense guidelines, potentially leading to more accurate flood safety assessments for coastal infrastructure.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104776"},"PeriodicalIF":4.2,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144168337","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}
Coastal EngineeringPub Date : 2025-05-22DOI: 10.1016/j.coastaleng.2025.104772
Niels van der Vegt , Jord J. Warmink , Bas Hofland , Vera M. van Bergeijk , Suzanne J.M.H. Hulscher
{"title":"Variation in flow characteristics of overtopping waves on dike crests","authors":"Niels van der Vegt , Jord J. Warmink , Bas Hofland , Vera M. van Bergeijk , Suzanne J.M.H. Hulscher","doi":"10.1016/j.coastaleng.2025.104772","DOIUrl":"10.1016/j.coastaleng.2025.104772","url":null,"abstract":"<div><div>During severe storms, waves can overtop dikes, leading to erosion of the crest and landward slope, which may ultimately result in breaching. To accurately model this erosion, the overtopping flow needs to be described in a time-dependent manner for each individual wave overtopping event. The peak flow velocity (<span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>) and peak flow thickness (<span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>) are critical boundary conditions in this context. Previous studies have shown that these flow characteristics are related to the overtopping volume, yet often propose deterministic models that overlook the variability and interdependency between these characteristics.</div><div>The goal of this study is to address these gaps by explicitly quantifying the variation and interdependence of <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>, using data from small-scale FlowDike experiments. We propose generalized distributions to describe the variation in these flow characteristics, with <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> varying by 13% to 23%, depending on the waterside slope angle, and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> varying by approximately 20%. Furthermore, the interdependency between <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> is modeled using a Student-t copula (<span><math><mrow><mi>ν</mi><mo>=</mo><mn>9</mn><mo>.</mo><mn>361</mn></mrow></math></span>, <span><math><mrow><mi>ρ</mi><mo>=</mo><mo>−</mo><mn>0</mn><mo>.</mo><mn>497</mn></mrow></math></span>), revealing a moderate negative correlation. This suggests that overtopping events with a high <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> are less likely to have a large <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>, and vice versa.</div><div>The findings of this study can be directly applied to improve models that describe the loading caused by overtopping waves and the resulting erosion. By incorporating the variation and interdependence of <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104772"},"PeriodicalIF":4.2,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154827","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}
Coastal EngineeringPub Date : 2025-05-16DOI: 10.1016/j.coastaleng.2025.104789
Shih-Feng Su , Gangfeng Ma
{"title":"Boussinesq modeling of typhoon-induced infragravity oscillations in Hualien Harbor, eastern Taiwan: Influence of the adjacent coast","authors":"Shih-Feng Su , Gangfeng Ma","doi":"10.1016/j.coastaleng.2025.104789","DOIUrl":"10.1016/j.coastaleng.2025.104789","url":null,"abstract":"<div><div>Large infragravity-wave oscillations inside harbors are generally induced by typhoon-generated swell waves. The interaction between infragravity waves and harbor geometry can significantly amplify wave oscillations when the specific frequencies match the natural resonance frequencies of the harbor. Additionally, the neighboring coastal morphology can enhance the influx of infragravity energy. In this study, we investigated infragravity oscillations in Hualien Harbor, eastern Taiwan, during the passage of a strong typhoon. The harbor geometry comprises outer and inner basins aimed at providing a well-sheltered area. However, the extreme infragravity wave height of 2.0 m was observed at the innermost basin. A wave-resolving Boussinesq model was applied to reproduce harbor oscillations and was validated against the measured data within the port. The accuracy of the simulated significant wave heights was sensitive to the direction of the incident wave, but not that of the simulated infragravity waves. Furthermore, lower and higher resonance frequencies prevail in the inner and outer basins, respectively. The simulated spatial distributions of wave heights in the resonance periods demonstrated that these waves were present both within the harbor and along the adjacent coast. Additionally, the refraction effects of the adjacent coast were investigated through numerical simulations. Our experiments revealed that the infragravity energy generated on the adjacent coast contributed to an increase in infragravity wave heights inside the harbor up to 47 %. Moreover, we found that reducing the long-period infragravity waves significantly altered the distribution of short-period swell waves in the outer harbor basin.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104789"},"PeriodicalIF":4.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105100","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}
Coastal EngineeringPub Date : 2025-05-16DOI: 10.1016/j.coastaleng.2025.104788
Yanxu Wang , Quanlin Qiu , Zegao Yin , Xiutao Jiang , Xuan Zhang
{"title":"Drag coefficient prediction model for simulating breaking waves propagating on partly submerged vegetated sloping beaches using a RANS model","authors":"Yanxu Wang , Quanlin Qiu , Zegao Yin , Xiutao Jiang , Xuan Zhang","doi":"10.1016/j.coastaleng.2025.104788","DOIUrl":"10.1016/j.coastaleng.2025.104788","url":null,"abstract":"<div><div>Accurate prediction of vegetation drag coefficients (<em>C</em><sub>D</sub>) is crucial for simulating breaking wave propagation on partly submerged vegetated sloping beaches. This study conducted a comprehensive investigation involving physical experiments and numerical modeling to address the limitations of existing empirical formulas for <em>C</em><sub>D</sub>. The experiments varied incident wave heights (<em>H</em><sub>i</sub> = 0.02–0.10 m), wave periods (<em>T</em> = 1.0–1.8 s), vegetation densities (<em>N</em><sub>v</sub> = 41–590 units/m<sup>2</sup>), vegetation zone lengths (<em>L</em><sub>v</sub> = 0.8–1.6 m), and beach slope gradients (<em>m</em> = 1/10–1/30), generating a database of 750 calibrated <em>C</em><sub>D</sub> values. Numerical simulations using a Reynolds-Averaged Navier-Stokes (RANS) model coupled with the stabilized <em>k−ω</em> SST turbulence model and the volume-of-fluid (VOF) method revealed that <em>C</em><sub>D</sub> correlates strongly with the Iribarren number (<em>ξ</em><sub>0</sub>), while being highly sensitive to vegetation density and zone length. Two prediction models were developed: a multivariate nonlinear regression (MNLR) model and an M5P-tree machine learning model. Both models utilized <em>ξ</em><sub>0</sub>, vegetation volume fraction (<em>φ</em>), and relative vegetation zone length (<em>λ</em><sub><em>L</em></sub>) as input parameters. The MNLR model provided a compact formula with moderate accuracy (<em>R</em> = 0.87, <em>RMSE</em> = 0.77), while the M5P-tree model partitioned the parameter space using <em>φ</em> and <em>ξ</em><sub>0</sub>, generating three tailored sub-models with superior performance (<em>R</em> = 0.91, <em>RMSE</em> = 0.64). Further validation with independent datasets confirmed that the M5P-tree model outperformed the MNLR model in simulating wave height evolution over vegetated sloping beaches. These findings demonstrate the potential of the M5P-tree model as a robust tool for enhancing simulations of breaking wave propagation on vegetated sloping beaches and optimizing vegetated coastal defenses.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104788"},"PeriodicalIF":4.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105099","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}
Coastal EngineeringPub Date : 2025-05-13DOI: 10.1016/j.coastaleng.2025.104775
Chen Peng, Dezhi Ning, Lifen Chen, Jin Xu, Hao Cao
{"title":"Numerical and experimental investigation on ‘C-pile’ breakwaters for wave attenuation","authors":"Chen Peng, Dezhi Ning, Lifen Chen, Jin Xu, Hao Cao","doi":"10.1016/j.coastaleng.2025.104775","DOIUrl":"10.1016/j.coastaleng.2025.104775","url":null,"abstract":"<div><div>The growing threat of wave-induced impacts to coastal sustainability necessitates effective wave attenuation strategies. Breakwaters play a pivotal role in mitigating wave energy, with resonant breakwaters leveraging Bragg and localized resonance mechanisms showing significant promise. This study investigates the wave attenuation performance of a novel C-shaped cylindrical (i.e., C-pile) breakwater through physical experiments and numerical simulations. The reflection coefficient, transmission coefficient, and time histories of water levels were measured through wave flume experiments, with the data used to validate a three-dimensional numerical model constructed in OpenFOAM and predictions from Bloch theory based on linear potential flow. Parametric numerical simulations were systematically conducted to explore the effects of opening width, chamber area, opening angle, and submergence depth on the wave attenuation performance and resonance behavior of individual C-piles. Localized optimization of C-pile arrays was conducted to enhance wave attenuation for specific wave period ranges. Results demonstrate that wave attenuation by C-piles is driven by chamber-wave interactions, where fluctuations in water level and volume within the chamber contribute to wave attenuation. The incident wave frequency and the resonant frequency of the C-pile follow a specific relationship. The latter has a close relationship with the structural dimensions. While parametric adjustments improved attenuation for target wave periods, uniform array modifications did not guarantee consistent performance gains. These findings establish the potential of C-piles as effective alternatives to traditional breakwaters, offering insights into resonance-based attenuation mechanisms and tailored optimization strategies.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104775"},"PeriodicalIF":4.2,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072502","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}
Coastal EngineeringPub Date : 2025-05-10DOI: 10.1016/j.coastaleng.2025.104771
Yanyu He , Feng Cai , Jianhui Liu , Hongshuai Qi , Bailiang Li , Chao Cao , Shaohua Zhao , Gen Liu , Xu Chen , Jiaqi Huang
{"title":"A framework to mitigate aeolian erosion on nourished beaches","authors":"Yanyu He , Feng Cai , Jianhui Liu , Hongshuai Qi , Bailiang Li , Chao Cao , Shaohua Zhao , Gen Liu , Xu Chen , Jiaqi Huang","doi":"10.1016/j.coastaleng.2025.104771","DOIUrl":"10.1016/j.coastaleng.2025.104771","url":null,"abstract":"<div><div>Beach nourishment has become a widely adopted nature-based strategy for coastal protection worldwide. However, in regions prone to strong winds, the topographic changes induced by beach nourishment—particularly elevated nourished berms—can significantly alter near-surface wind fields and aeolian sand transport processes. This study integrates field observations with numerical modeling to examine how topographic modifications induced by beach nourishment can influence the coastal aeolian sand transport mechanisms. The key findings are as follows: (1) The elevated beach berms lead to a localized increase in wind speed and a segmented fetch system, with the latter plays a dominant role in limiting the development and transport of aeolian sand streamers; (2) By incorporating the interactions between the transport-stimulated effect of wind intensification and the transport-limited effect of fetch segmentation induced by nourished berm, a “piecewise” model framework was proposed for the aeolian sand transport of nourished beaches, which significantly improving the accuracy of numerical modeling; (3) Based on the improved sand transport model, an optimal beach nourishment design for windy coasts was discussed, and a multi-tiered, mechanically graded berm nourishment approach was recommended to minimize the aeolian sand transport across beach surface.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104771"},"PeriodicalIF":4.2,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068357","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}