Coastal Engineering最新文献

{"title":"A probabilistic coral rubble mechanical instability model applied with field observations from the Great Barrier reef","authors":"Dongfang Liu,&nbsp;David P. Callaghan,&nbsp;Ananth Wuppukondur,&nbsp;Tom E. Baldock","doi":"10.1016/j.coastaleng.2024.104655","DOIUrl":"10.1016/j.coastaleng.2024.104655","url":null,"abstract":"<div><div>Unstable coral rubble hinders coral recruitment and recovery of coral reefs after damage from cyclones and bleaching events. If coral rubble remains unstable under typical everyday environmental conditions, areas of coral rubble will not be able to recover. Evaluating the probability of rubble instability over regional scale reef systems can assist the optimization of coral reef restoration efforts. Currently, robust and verified models for such applications do not exist. This paper presents a comprehensive assessment method to predict the probability of coral rubble instability, which combines a fluid-structural interaction approach with a statistical regional wave climate model. The hydrodynamic model employs non-linear wave theory to determine near-bed velocity, pressure gradients, and the corresponding drag and inertia forces acting on the coral rubble. The instability model assesses when overturning or sliding forces exceed resisting forces, considering thousands of combinations of different coral sizes and densities to calculate the proportion of instability under a given wave forcing. The model was calibrated and validated using prior laboratory experiments as reported by Kenyon et al. (2023b). The hydrodynamic and instability models use an extensive dataset of non-cyclonic wave climates (hindcast from over 30 years of wind measurements) specific to the region around Heron Reef, Great Barrier Reef, Australia, enabling a comprehensive evaluation of the probability of rubble instability in this area. Results indicate that the overall probability of rubble instability <span><math><mrow><mo>(</mo><msub><mi>Pr</mi><mn>3</mn></msub><mo>)</mo></mrow></math></span> reaches 0.74 in water depths less than 2 m (typical of reef crests or reef flats), while it declines to below 0.21 at a depth of 12 m (typical deeper parts of the fore reef). Coral rubble on reef crests near Heron Reef, which are sheltered by surrounding formations, demonstrates low probability of instability. Thus, coral rubble instability is influenced by both its specific location within the reef and the position of the reef relative to other nearby reefs. By integrating the rubble instability model with non-cyclonic wave climate data, a map of the probability of rubble instability was generated for eight reefs in the Capricorn and Bunker Group (CBG). This map provides valuable guidance for coral reef restoration efforts, significantly reducing the need for extensive field-based data.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104655"},"PeriodicalIF":4.2,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical modelling of pump-driven tsunami generation and fluid-structure-interaction in idealized urbanized coastal areas during run-up","authors":"Felix Spröer ,&nbsp;León-Carlos Dempwolff ,&nbsp;Christian Windt ,&nbsp;Clemens Krautwald ,&nbsp;David Schürenkamp ,&nbsp;Nils Goseberg","doi":"10.1016/j.coastaleng.2024.104654","DOIUrl":"10.1016/j.coastaleng.2024.104654","url":null,"abstract":"<div><div>Tsunami wave inundations are still one of the most devastating natural disasters worldwide. Tsunamis striking a settlement frequently devastate much of its infrastructure. In instances where infrastructure withstands the tsunami’s actions, it acts as a flow resistance for the wave’s run-up, altering inundation dynamics and flow depth. Accurately predicting the complex dynamics of tsunami wave run-up in densely populated urban areas is paramount for informing effective evacuation protocols and conducting comprehensive hazard and risk assessments. In pursuit of improving wave run-up prediction capabilities, this study delves into the three-dimensional numerical modelling of wave run-up of non-breaking, long tsunami waves in urbanized areas. Leveraging insights from a physical experiment with pump-driven wave generation and idealized infrastructure, a novel pressure-based wave generation boundary condition is developed. The boundary condition achieves an average of 4.9% accuracy in replicating the water surface elevation from experiments. Additionally, it attains an average 1.5% precision in reproducing flow velocities, furthermore reproducing the spatial flow dynamics accurately. Physical experiment wave run-up is modelled with an average 6.9% deviation for both simulations with and without idealized infrastructure. 63.0% higher non-linearity waves than in the physical experiments are additionally investigated to highlight the boundary conditions capabilities of high non-linearity wave generation, change in run-up reduction for higher non-linearity waves for infrastructure interaction and furthermore in-depth flow field characteristics during tsunami inundation. Finally, the study highlights deviations from analytically calculated wave run-up, emphasizing the necessity for numerical and physical experimental evaluation for both high non-linearity waves and tsunami infrastructure interaction, ultimately fostering both resilience and preparedness against tsunami hazards.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"196 ","pages":"Article 104654"},"PeriodicalIF":4.2,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy balance during Bragg wave resonance by submerged porous breakwaters through a mixture theory-based δ-LES-SPH model","authors":"Yong-kun Chen ,&nbsp;Domenico D. Meringolo ,&nbsp;Yong Liu ,&nbsp;Jia-ming Liang","doi":"10.1016/j.coastaleng.2024.104652","DOIUrl":"10.1016/j.coastaleng.2024.104652","url":null,"abstract":"<div><div>This paper presents a numerical analysis of the time behaviors of mechanical and internal fluid energies during the Bragg wave resonance induced by two-arrayed trapezoidal submerged porous breakwaters based on a reformatted <em>δ</em>-LES-SPH model (Di Mascio et al., 2017). In the present work, a mixture theory is introduced into the <em>δ</em>-LES-SPH model by reformulating the governing equations with the incorporation of a volume fraction. In this approach, the viscous and diffusive terms are also modified by the volume fraction. The energy equation is then written for the presented model highlighting the presence of two additional components compared with the classical <em>δ</em>-LES-SPH formulation: one coming from the fluid compression and another one due to the dissipation both induced by the interaction of the porous structure with the fluid phase. The numerical results are validated by available experimental data for a gravity-driven mass flow passing through a porous dam case and two Bragg wave resonance by two-arrayed submerged trapezoidal porous breakwaters cases. A numerical analysis is then conducted on Bragg wave resonance by two-arrayed trapezoidal porous breakwaters, by investigating the effects of the distance between the two breakwaters and their porosity. Interesting insights about the type and magnitude of dissipation occurring during the wave-structure interaction are captured by analyzing the time evolutions of each energy component.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"196 ","pages":"Article 104652"},"PeriodicalIF":4.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660967","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}

{"title":"Experimental investigation on cross-shore profile evolution of reef-fronted beach","authors":"Yuan Li ,&nbsp;Chi Zhang ,&nbsp;Shubin Chen ,&nbsp;Hongshuai Qi ,&nbsp;Weiqi Dai ,&nbsp;Huimin Zhu ,&nbsp;Titi Sui ,&nbsp;Jinhai Zheng","doi":"10.1016/j.coastaleng.2024.104653","DOIUrl":"10.1016/j.coastaleng.2024.104653","url":null,"abstract":"<div><div>Physical experiments on cross-shore profile evolution of the reef-fronted beach are conducted considering various offshore wave conditions and reef settings. Cross-shore beach profile evolution, sediment transport rate, and waves at the beach toe are analyzed. The reef-fronted beach is found to be resilient to erosion induced by offshore sediment transport. In present cases, the beach evolves from a sloping profile to a reflective profile, and onshore sediment transport leads to the formation of a swash berm. Both the shortwaves and infragravity waves at the beach toe play an important role in forming the beach shape. The berm foreshore slope mainly depends on the wave energy density in the infragravity band at the beach toe. Wave energy density in the shortwave band at the beach toe increases with reef submergences, while wave energy density in the infragravity band at the beach toe increases with offshore wave heights. The temporal evolution of sediment transport rate exhibits two modes, implying complex feedbacks occur between swash flows and beach profile evolution. The bulk transport on the reef-fronted beach is parameterized by the relative height of shortwaves and wave steepness of both shortwaves and infragravity waves at the beach toe. A conceptual model of bulk transport on the beach is proposed that the bulk transport increases with the Gourlay number, indicating that reef-fronted beaches with a well-developed reef flat are resilient to increasing wave exposure.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104653"},"PeriodicalIF":4.2,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652930","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}

{"title":"Interactions between swell and colinear wind short crested waves, following and opposing","authors":"Fabio Addona ,&nbsp;Maria Clavero ,&nbsp;Luca Chiapponi ,&nbsp;Sandro Longo","doi":"10.1016/j.coastaleng.2024.104649","DOIUrl":"10.1016/j.coastaleng.2024.104649","url":null,"abstract":"<div><div>When wind blows over a water surface during a swell, it generates short-crested, three-dimensional waves that interact with the underlying flow field through a mechanism that ultimately increases the average energy. In the present work, two test cases in which wind is flowing following and opposing a swell are analysed with experiments and are compared with wind–waves-only and swell-only cases. The analysis of the free surface fluctuation and of the flow field, with the three components of fluid velocity measured at the same time through a stereo particle image velocimetry system, leads to an accurate quantification of the energy distribution, of the structure of the oscillating, fluctuating (due to wind–waves) and turbulent kinetic energy, without assumptions on the structure of the flow. The findings demonstrate that the transverse dynamics is a pivotal factor in the transfer of energy in the near-free surface domain, and elucidate the energy transfer between wind–waves and swell. The results also confirm the reduction of oscillating kinetic energy of the swell in the presence of short wind–waves, a process interpreted with different possible mechanisms. There is evidence of the enhancement of wind action in the presence of swell compared to that in the case of wind–waves-only, confirming that energy transfer from the wind to the sea is enhanced when wind flows over a swell. Consequently, when the fetch is influenced by swells generated or propagated from different regions, and during multi-peak sea storms, wave generation models should account for this amplification.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104649"},"PeriodicalIF":4.2,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remote sensing of wave-orbital velocities in the surfzone","authors":"Tyler McCormack ,&nbsp;Julia Hopkins ,&nbsp;Britt Raubenheimer ,&nbsp;Steve Elgar ,&nbsp;Katherine L. Brodie","doi":"10.1016/j.coastaleng.2024.104631","DOIUrl":"10.1016/j.coastaleng.2024.104631","url":null,"abstract":"<div><div>Wave-orbital velocities are estimated with particle image velocimetry (PIV) applied to rapid sequences of images of the surfzone surface obtained with a low-cost camera mounted on an amphibious tripod. Time series and spectra of the remotely sensed cross-shore wave-orbital velocities are converted to the depth of colocated acoustic Doppler velocimeters (ADVs), using linear finite depth theory. These converted velocities are similar to the velocities measured in situ (mean nRMSE for time series = 16% and for spectra = 10%). Small discrepancies between depth-attenuated surface and in situ currents may be owing to errors in the surface velocity measurements, uncertainties in the water depth, the vertical elevation of the ADVs, and the neglect of nonlinear effects when using linear finite depth theory. These results show the potential to obtain spatially dense estimates of wave velocities using optical near-field remote methods during field campaigns and continuous monitoring operations.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104631"},"PeriodicalIF":4.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652933","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}

{"title":"Developing a decision tree model to forecast runup and assess uncertainty in empirical formulations","authors":"Michael Itzkin,&nbsp;Margaret L. Palmsten,&nbsp;Mark L. Buckley,&nbsp;Justin J. Birchler,&nbsp;Legna M. Torres-Garcia","doi":"10.1016/j.coastaleng.2024.104641","DOIUrl":"10.1016/j.coastaleng.2024.104641","url":null,"abstract":"<div><div>The coastal zone is a dynamic region that can change rapidly and significantly with respect to the morphology of the beach and incoming wave conditions. Runup forecasts may be improved by adapting a dynamic approach that allows for different runup models to be implemented in response to changes in beach state. Accurately forecasting wave runup is critical to characterize exposure to coastal hazards and provide an early warning against potential erosion and inundation. Here, we developed a decision tree model to produce a weighted ensemble of existing runup models to predict 1.25 years of runup at Duck, North Carolina, USA. We then applied the calibrated decision tree model to reproduce observed runup during the DUNEX experiment in Pea Island, North Carolina, USA. We found that the decision tree approach yielded a prediction that was comparable or greater in accuracy (i.e. higher r², lower RMSE) than the individual runup models. We also interrogated the decision tree predictions to determine how the individual models perform relative to each other and why certain models perform better than others under the same observed wave and beach conditions. We found that the decision tree approach drew on the processes represented in the individual models in the ensemble to produce a forecast that is accurate and explainable without relying on prior knowledge of the study site(s) or requiring manual adjustments beyond the initial model training.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104641"},"PeriodicalIF":4.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparison of eight weakly dispersive Boussinesq-type models for non-breaking long-wave propagation in variable water depth","authors":"Guillaume Coulaud ,&nbsp;Maria Teles ,&nbsp;Michel Benoit","doi":"10.1016/j.coastaleng.2024.104645","DOIUrl":"10.1016/j.coastaleng.2024.104645","url":null,"abstract":"<div><div>Weakly dispersive Boussinesq-type models are extensively used to model long-wave propagation in coastal areas and their interaction with coastal infrastructures. Many equations falling in this category have been formulated during the last decades, but few detailed comparisons between them can be found in the literature. In this work, we investigate theoretically and with computational experiments eight variants of the most popular models used by the coastal engineering community. Both weakly nonlinear and fully nonlinear models are considered, hoping to understand better when the additional complexity of the latter class of models is necessary or justified. We provide an overview and discuss the properties of these models, including the linear dispersion relation in uniform water depth, the second-order nonlinear coupling coefficient, the shoaling gradient, and the sensitivity to wave trough instabilities. The models are then numerically discretised using the same general strategy in a single numerical code, using fourth-order methods for time and space discretisation. Their capacity to simulate coastal wave propagation and their transformation when approaching the shore is assessed on three challenging one-dimensional benchmarks. It appears that fully nonlinear models are more consistent than their weakly nonlinear counterparts, which can occasionally perform better but show different behaviours depending on the case.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104645"},"PeriodicalIF":4.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573348","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}

{"title":"Group interaction effect on breaking wave forces on a vertical pile: Experimental tests and predictive models","authors":"Xiutao Jiang ,&nbsp;Zegao Yin ,&nbsp;Yanxu Wang ,&nbsp;Rengong Zhang","doi":"10.1016/j.coastaleng.2024.104651","DOIUrl":"10.1016/j.coastaleng.2024.104651","url":null,"abstract":"<div><div>Pile groups are extensively utilized as supports for many coastal structures, such as bridges, jetties, and oil production platforms. The problem of understanding the interaction effects within pile groups and predicting the breaking wave forces on them is considered in this paper, using experimental tests and machine learning-based predictive modeling. The restriction of previous studies on this important engineering problem is that the pile group arrangements considered are limited. Prediction methods are therefore developed only for specific pile group arrangements and do not incorporate the effect of the incident wave direction. In this study, to partially overcome this limitation, an extensive experimental investigation is conducted on 70 different pile group arrangements under six breaking wave conditions. Three pile group coefficients, characterized by the total, quasi-static, and dynamic forces, are introduced for a thorough assessment of the interaction effects within the pile group. First, the pile group coefficients for three basic arrangements (tandem, side-by-side, and staggered) are evaluated. The results reveal a sheltering effect in the tandem arrangement and an amplification effect in the side-by-side arrangement. However, the forces on the measured pile in the staggered arrangement resemble those on the isolated pile, with neither significant sheltering nor amplification effects observed. Then, the results for all arrangements highlight the significant effect of wave direction on the pile group coefficients for small inter-pile spacing. Finally, different machine learning algorithms are adopted to develop predictive models for the group coefficients. The XGBoost model demonstrates superior accuracy for predicting the total and quasi-static force coefficients, while the dynamic force coefficient remains challenging to predict accurately due to its stochastic nature.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104651"},"PeriodicalIF":4.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652929","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}

{"title":"Study on whitecapping dissipation process for wave modelling during tropical cyclones","authors":"Wenxuan Sun ,&nbsp;Zhuxiao Shao ,&nbsp;Bingchen Liang ,&nbsp;Huijun Gao","doi":"10.1016/j.coastaleng.2024.104650","DOIUrl":"10.1016/j.coastaleng.2024.104650","url":null,"abstract":"<div><div>The atmosphere-wave interaction is an important physical process during tropical cyclones. Understanding and modelling of this process are of great significance for the technical and functional design of coastal and harbor structures. At the high wind velocities of tropical cyclones, foams and sprays that are blown away from the sea form a slip layer between the atmosphere and the sea surface. This slip layer makes the atmosphere-wave interaction exhibit different characteristics compared with that at low wind velocities. The significant effect of this layer on the atmosphere is the reduction of aero-dynamical surface roughness, which has been used to improve the expression of the drag coefficient. On this basis, the effect of the slip layer on the sea surface is further explored in this study. The whitecap coverage may reach a low limit at high wind velocities, and a modified numerical method of whitcapping dissipation for the wave spectrum model is proposed based on the classic field observations of whitecaps. According to these observations, when developing waves appear, the variation characteristics of whitecap coverage are different from those of developed waves with low wind velocities. Thus, the critical friction velocity of wave states should be defined, which can be expressed by the threshold steepness of developed waves due to the negative correlation between wave age and wave steepness. The dissipation mode is then modified to gradually reach the limit with the increase of friction velocities, which is validated during 24 tropical cyclones measured with 26 buoys. The negative Bias of the default mode generally decreases with the increase of friction velocity, even reaching −0.8 m, while the Bias of the modified mode is mostly maintained between 0.2 m and −0.2 m.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"195 ","pages":"Article 104650"},"PeriodicalIF":4.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552562","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}