Coastal Engineering最新文献_第6页

Mechanisms of sediment bypassing pathways in the mixed sand-gravel inlets 泥沙绕过混合沙砾入口通道的机制

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-10-30 DOI: 10.1016/j.coastaleng.2025.104901

Jie Gong, Helene Burningham

Inlet systems play a vital role in protecting coastal regions from wave action, where their ebb-tidal deltas reduce wave energy but also facilitate alongshore sediment transport through bypassing processes. Most studies on sediment bypassing have focused on sandy inlet systems, but the more complex sedimentary and hydrodynamic factors controlling the morphodynamics of mixed sand-gravel inlets has not been widely addressed. This study investigates wave- and current-driven gravelly sediment bypassing pathways in the mixed sand-gravel Deben Inlet, southeast UK by integrating sediment grain-size analysis, surface sedimentary environment mapping, wave modelling, tidal current speed estimation, and empirical hydrodynamic relationships. The inlet is dominated by medium gravel and coarse sand, with over 98% of samples containing gravel components and dominant grain sizes range between 1 mm and 16 mm. Wave simulations demonstrate that NE and E storm waves drive both alongshore and cross-shore transport across the shoals and ebb jets, while S waves tend to induce northward alongshore transport. Increased wave energy enhances the competency to mobilize coarser sediments, with E waves being more effective than S and NE waves under the same conditions. A simplified model estimating tidal current speed suggests that both ebb and flood flows during spring tides are capable of transporting gravel; neap tidal currents are limited to sand. Sediment transported alongshore is stored in a small updrift gravelly spit, before being released by ebb currents into the ebb-delta system and reworked by waves via cross-shore and alongshore transport. NE and E waves drive the formation of swash bars that encourage swatchway deepening, while S waves tend to flatten shoals and encourage swatchway closure, together promoting the morphological complexity of the mixed sand-gravel ebb-tidal delta.

入口系统在保护沿海地区免受波浪作用方面发挥着至关重要的作用，在那里，它们的退潮三角洲减少了波浪能量，但也通过绕过过程促进了沿岸沉积物的运输。大多数关于泥沙绕过的研究都集中在砂质入口系统上，但控制混合砂砾质入口形态动力学的更复杂的沉积和水动力因素尚未得到广泛研究。本研究通过综合沉积物粒度分析、地表沉积环境测绘、波浪建模、潮流速度估计和经验水动力关系，研究了英国东南部混合沙砾德本湾波浪和水流驱动的砾石沉积物绕过路径。入口以中砾石和粗砂为主，超过98%的样品含有砾石成分，主要粒度在1 ~ 16 mm之间。波浪模拟结果表明，东北向和东向风暴波驱动浅滩和退潮射流的沿岸和跨海岸运输，而南向风暴波则倾向于诱导向北的沿岸运输。波浪能的增加增强了对较粗沉积物的动员能力，在相同条件下，E波比S波和NE波更有效。一个简化的潮流速度估计模型表明，大潮期间的退潮和涨潮都能够输送砾石；小潮潮流仅限于沙子。沿着海岸移动的沉积物储存在一个小的向上漂流的砾石吐槽中，然后被退潮流释放到退潮三角洲系统中，并通过跨海岸和沿海岸的移动被海浪重新加工。NE波和E波驱动冲积坝的形成，促使河道加深，而S波则使浅滩变平，促使河道关闭，共同促进了混合沙砾潮滩三角洲形态的复杂性。

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引用次数: 0

Evaluating portable reef for mangrove sapling protection: An experimental study using live mangroves 评估红树林树苗保护的便携式珊瑚礁：以活红树林为研究对象的实验研究

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-10-29 DOI: 10.1016/j.coastaleng.2025.104903

Sindhu Sreeranga, Jiarui Lei

Mangrove restoration in high-energy coastal zones is often hindered by hydrodynamic forces that uproot saplings, compromising their establishment. This study evaluates a portable reef designed to reduce wave induced oscillation forces on Rhizophora mangle saplings, tested under regular waves in a wave basin. Saplings were grown for eight months and exposed to wave periods of 0.8–1.4sec and heights of 4–10 cm. When tested in emerged and submerged configurations, the portable reef reduced sapling oscillations by 63 % and 33 %, respectively, compared to saplings without reef protection. The reef lowered displacement amplification ratios (D_amp) by 72 % and 55 %, demonstrating a stabilizing effect against wave-induced forces. Wave transmission coefficients (K_T) ranged from 0.53 to 1, highlighting the reef's ability to attenuate wave energy. Root uprooting strength in protected saplings from reef (8.49N) remained comparable to control specimens (8.92N) not exposed to waves. However, unprotected saplings exhibited reduced root strength (3.71N), emphasizing the higher mechanical stress acting on plants. The reef exhibited structural stability throughout testing, with no displacement of individual stones. The portable reef can be removed and reused after sapling establishment. However, the timing is site and species-dependent and should be guided by field monitoring. Findings show it effectively reduces wave stress, stabilizes saplings, and supports mangrove restoration in dynamic coasts.

在高能量的沿海地区，红树林的恢复常常受到水动力的阻碍，这些水动力会将树苗连根拔起，从而影响它们的生长。本研究评估了一种便携式暗礁，该暗礁设计用于减少波浪诱导的振荡力，并在波浪盆地的规则波浪下进行了测试。树苗生长8个月，暴露在0.8 - 1.4秒的波浪周期和4-10厘米的高度。当在水面和水下配置中进行测试时，与没有礁石保护的树苗相比，便携式礁石分别减少了63%和33%的树苗振荡。礁体将位移放大比（阻尼）降低了72%和55%，显示出对波浪诱导力的稳定作用。波浪透射系数（KT）从0.53到1不等，突出了珊瑚礁衰减波浪能量的能力。受保护的珊瑚礁树苗（8.49N）的根系拔根强度与未暴露于波浪的对照标本（8.92N）相当。然而，未受保护的树苗根系强度降低（3.71N），表明施加在植株上的机械应力较高。在整个测试过程中，珊瑚礁表现出结构稳定性，没有单个石头的位移。树苗建立后，可移走可重复使用的便携式暗礁。然而，时间取决于地点和物种，应以现场监测为指导。研究结果表明，它可以有效地减少波浪应力，稳定树苗，并支持动态海岸红树林的恢复。

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引用次数: 0

Physics-based unified formulation for predicting clear-water equilibrium scour depth and scour threshold velocity around piles 基于物理的清水平衡冲刷深度和桩周冲刷阈值速度预测统一公式

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-11-01 DOI: 10.1016/j.coastaleng.2025.104906

Wen-Gang Qi , Biao Li , Shun-Yi Wang , Yong Wan , Pei-Qing Zhao , Fu-Ping Gao

Existing prediction formulas for equilibrium local scour depth around pile foundations remain largely phenomenological, predominantly derived through dimensional analysis supplemented by empirically calibrated coefficients. Such approaches often inadequately represent the underlying scour physics, potentially leading to significant prediction inaccuracies. To address this fundamental limitation, this study develops and validates a novel physics-explicit formulation grounded in turbulence phenomenology. By systematically integrating two key physical mechanisms—(1) a scaling expression for the local bed shear stress acting on sediment particles within the scour hole, derived from Kolmogorov's turbulence theory and energetic principles, and (2) a geometric scaling framework for the initial primary horseshoe vortex dimensions—a universal expression for clear-water equilibrium scour depth around cylindrical piles is derived. Critically, this formulation inherently encapsulates the threshold flow velocity required for scour initiation around the pile, a pivotal physical constraint often overlooked in prior models. Validation against a comprehensive dataset comprising 501 experimental cases demonstrates the superior predictive performance of the proposed formula over conventional empirical approaches and recent turbulence-based models. Further derivation yields a scour threshold velocity for local scour initiation around piles. This parameter shows consistent agreement with experimental data across varying conditions, consistently falling within the established range of 0.3–0.6.

现有的桩基周围平衡局部冲刷深度预测公式在很大程度上仍然是现象学的，主要是通过量纲分析和经验校准系数来推导的。这种方法往往不能充分代表潜在的冲刷物理，可能导致严重的预测不准确。为了解决这一基本限制，本研究开发并验证了一种基于湍流现象学的新型物理显式公式。通过系统地整合两个关键的物理机制——(1)由Kolmogorov湍流理论和能量原理推导出的作用于冲刷孔内沉积物颗粒的局部河床剪应力的标度表达式，以及(2)初始初级马蹄涡尺寸的几何标度框架——推导出圆柱桩周围清水平衡冲刷深度的通用表达式。至关重要的是，该公式固有地封装了桩周围冲刷起始所需的阈值流速，这是先前模型中经常忽略的关键物理约束。对包含501个实验案例的综合数据集的验证表明，所提出的公式比传统的经验方法和最近基于湍流的模型具有更好的预测性能。进一步推导出桩周局部冲刷起始的冲刷阈值速度。该参数在不同条件下与实验数据一致，始终落在0.3-0.6的既定范围内。

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引用次数: 0

Amplification of nonlinear response of floating photovoltaics by coastal topography: Experimental and numerical study 沿海地形对浮动光伏非线性响应的放大：实验和数值研究

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-09-18 DOI: 10.1016/j.coastaleng.2025.104876

Qiujue Jiang , Deqing Zhang , Junfeng Du , Qingping Zou , Anteng Chang , Huajun Li

Nearshore coastal regions have become popular for floating photovoltaics (FPV) installations. During propagation over seabed topography towards nearshore FPV systems, waves undergo intricate transformations by shoaling, reflection and refraction, potentially influencing hydrodynamic responses of these emerging marine renewable energy structures in ways that are not well understood. Therefore, wave flume experiments and multiscale fully coupled time-domain fluid-structure interaction (FSI) simulations are performed to examine the topography effect on the nonlinear responses of nearshore FPV systems at a field site in the East China Sea. Experimental results reveal that near-resonant wave interactions in coastal regions drive significant energy transfer among different wave frequencies, amplifying the nonlinear dynamic responses of FPV systems by channeling energy toward their natural modes. As a result, second-order heave and pitch responses are amplified by up to 117.87 % and 136.38 % compared to the case without topography, which in turn lead to an increase in mooring tension. Moreover, the topography-induced amplification of nonlinear wave harmonics enhances the surge mean drift of FPV. This enhancement exhibits a negative correlation with the relative FPV length with respect to the wavelength. Comparisons between experiments and fully coupled simulations for irregular waves indicate that neglecting topography causes the FPV dynamic response model to produce inaccurate estimations of heave/pitch motions, while FSI simulations forced by high-fidelity local wave fields predicted by the fully nonlinear Boussinesq wave model are capable of capturing the observed topographic effect. These findings provide the theoretical basis for design consideration of the safe, cost-effective deployment of efficient FPV systems in coastal waters.

近岸沿海地区已成为浮动光伏（FPV）安装的热门地区。在海底地形向近岸FPV系统传播的过程中，波浪通过浅滩、反射和折射经历了复杂的转变，可能以尚不清楚的方式影响这些新兴海洋可再生能源结构的水动力响应。为此，本文采用波浪水槽实验和多尺度全耦合时域流固耦合（FSI）模拟来研究地形对东海近岸FPV系统非线性响应的影响。实验结果表明，沿海地区的近共振波相互作用驱动不同波频之间的能量传递，通过将能量引导到其自然模态，放大了FPV系统的非线性动态响应。结果，与没有地形的情况相比，二阶升沉和俯仰响应放大了117.87%和136.38%，这反过来导致系泊张力增加。此外，地形引起的非线性谐波放大增强了FPV的浪涌平均漂移。这种增强与相对FPV长度相对于波长呈负相关。实验与不规则波的完全耦合模拟对比表明，忽略地形会导致FPV动力响应模型产生不准确的升沉/俯仰运动估计，而由完全非线性Boussinesq波模型预测的高保真局部波场强迫的FSI模拟能够捕捉到观测到的地形效应。这些发现为在沿海水域安全、经济地部署高效FPV系统的设计考虑提供了理论基础。

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引用次数: 0

Experimental study of bimodal spectral wave-induced dynamic responses in a silty seabed 粉质海底双峰谱波动力响应试验研究

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-10-03 DOI: 10.1016/j.coastaleng.2025.104890

Linlong Tong , Zhen Huang , Jisheng Zhang , Ning Chen , Dong-Sheng Jeng , Shulin Zhao , Xueyan Li

This study investigates the dynamic responses of silty seabeds to bimodal spectral wave loading, focusing on the impact of these waves on soil dynamics and liquefaction behavior. A series of laboratory experiments were conducted in a wave flume, simulating single-peaked wind waves, single-peaked swell waves, and bimodal spectral waves, which combine high-frequency wind waves and low-frequency swell waves. The results show that the pore pressures induced by bimodal spectral waves builds up over time, leading to a reduction in effective stress and shear strength. The buildup of pore pressures can cause residual liquefaction within a silty seabed, and the depth of liquefaction increases with wave height. When liquefaction occurs, the wave energy dissipates rapidly. The findings indicate that bimodal spectral waves induce deeper and more rapid liquefaction compared to single-peaked waves, with liquefaction progressing from the surface downward. Soil motion was analyzed using Particle Image Velocimetry (PIV), revealing complex flow patterns within the liquefied layers. Under single-peaked spectral wave conditions, shear flow was observed in the liquefied layer. However, under bimodal spectral wave conditions, both shear and plug flows were observed, with plug flow forming near the surface of the liquefied layer and shear flow occurring between the plug flow and the non-liquefied layer during the reversal phase of acceleration. Additionally, the soil particle velocity spectra exhibited multi-peak characteristics due to the nonlinear interactions of stress waves within the seabed.

本文研究了粉质海床对双峰谱波荷载的动力响应，重点研究了双峰谱波对土壤动力和液化行为的影响。在波浪水槽中进行了一系列室内实验，模拟了单峰风浪、单峰涌浪和高频风浪与低频涌浪相结合的双峰谱波。结果表明，双峰谱波引起的孔隙压力随时间增加，导致有效应力和抗剪强度降低。孔隙压力的积累会引起淤泥质海床的残余液化，且液化深度随波高的增加而增加。当液化发生时，波浪能迅速消散。结果表明，与单峰波相比，双峰谱波引起的液化更深、更快，液化从地表向下进行。利用粒子图像测速仪（PIV）分析了土壤运动，揭示了液化层内复杂的流动模式。在单峰谱波条件下，液化层中存在剪切流动。然而，在双峰谱波条件下，剪切流和塞流同时存在，在加速反转阶段，液化层表面附近形成塞流，塞流与非液化层之间发生剪切流。此外，由于海床内应力波的非线性相互作用，土壤颗粒速度谱呈现出多峰特征。

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引用次数: 0

Experiments and large eddy simulations of oscillatory flow over vortex ripples at high Reynolds number 高雷诺数涡旋波纹振荡流动的实验与大涡模拟

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-10-04 DOI: 10.1016/j.coastaleng.2025.104881

Weikai Tan , Jing Yuan , Deping Cao , Asim Önder

Long-crested sand ripples are ubiquitous seabed features in shallow coastal environments, characterized by the alternating generation of spanwise coherent vortices (SCVs) on either side of ripple crests. While previous studies have elucidated SCV dynamics at moderate Reynolds numbers (

R e \leq 1 0^{4}

), a range that is common at many beaches and can persist for long wave periods. Nonetheless, their applicability to higher Reynolds number conditions (

R e \sim 1 0^{5}

) remains uncertain. This investigation combines wall-modeled large eddy simulations (WMLES) and oscillating water tunnel experiments to examine SCV formation at high Reynolds numbers (

R e \sim O (1 0^{5})

). The WMLES approach employs a logarithmic wall model for rough surfaces, achieving accurate SCV representation with computational efficiency. Experimental validation demonstrates good agreement in both phase-averaged flow fields and turbulence statistics, confirming the model’s fidelity. Key findings reveal a Reynolds number dependence analogous to the drag crisis phenomenon: SCV intensity diminishes significantly for smooth ripples at

R e = O (1 0^{5})

, while surface roughness preserves vortex coherence. Our analysis of numerical results uncovers a positive feedback mechanism governing SCV development, where the residual SCV from the preceding half-cycle promotes early flow separation at ripple crests, facilitating vorticity accumulation and subsequent SCV formation. Analysis of the initial-cycle simulation (starting from a quiescent initial condition) shows that lee-side boundary layer must separate intrinsically during the deceleration phases of the first half-cycle to initiate this positive feedback loop. Both low Reynolds numbers and surface roughness can contribute to this first-half-cycle separation by increasing momentum deficit in the lee-side boundary layer.

长波峰沙纹是浅海环境中普遍存在的海底特征，其特征是在波峰两侧交替产生展向相干涡。虽然以前的研究已经阐明了中等雷诺数（Re≤104）下的SCV动力学，但这个范围在许多海滩上很常见，并且可以持续很长的波浪周期。尽管如此，它们对更高雷诺数条件（Re ~ 105）的适用性仍然不确定。这项研究结合了壁面模拟大涡模拟（WMLES）和振荡水洞实验来研究高雷诺数（Re ~ O(105)）下SCV的形成。WMLES方法采用了粗糙表面的对数壁模型，以计算效率实现了精确的SCV表示。实验验证表明，相平均流场和湍流统计数据吻合良好，证实了模型的保真度。关键发现揭示了一种类似于阻力危机现象的雷诺数依赖性：在Re= 0（105）时，平滑波纹的SCV强度显著减弱，而表面粗糙度保持了涡相干性。我们对数值结果的分析揭示了控制SCV发展的正反馈机制，其中前半周期的残余SCV促进了纹波波峰处的早期流动分离，促进了涡量积累和随后的SCV形成。初始周期仿真分析（从静态初始条件出发）表明，在前半周期的减速阶段，背风面边界层必须本质分离才能启动该正反馈回路。低雷诺数和表面粗糙度都可以通过增加背风侧边界层的动量赤字来促进这种前半循环分离。

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引用次数: 0

Transformation of Hm0 and Tm−1,0 over a model salt marsh 模型盐沼上Hm0和Tm−1,0的变换

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-10-30 DOI: 10.1016/j.coastaleng.2025.104900

Dimitrios Dermentzoglou , Marion Tissier , Jos R.M. Muller , Bas Hofland , Stijn Lakerveld , Bas W. Borsje , Alessandro Antonini

This research investigates how salt marshes contribute to both wave energy dissipation and spectral period transformation, advancing their role as a nature-based solution for coastal protection. Using laboratory simulations with a scaled barren foreshore, salt marsh and dike model, we examine the interactions between vegetation, water depth, and wave properties under varied conditions, including storm scenarios with irregular waves. Results indicate a case specific threshold at which the salt marsh model attenuates energy optimally, as for very shallow water depths wave energy is predominantly dissipated by the barren foreshore. The spectral wave period

T_{m - 1, 0}

increases when waves propagate from deep to shallow water depths, as a result of wave breaking and generation of infragravity waves. The presence of salt marsh vegetation further enhances this effect by preferentially damping high frequency components. This highlights that an increase in

T_{m - 1, 0}

in vegetated environments may not always correspond to an increased hydrodynamic load on the dike.

本研究探讨了盐沼如何促进波浪能量耗散和频谱周期转换，从而推进了盐沼作为基于自然的海岸保护解决方案的作用。通过实验室模拟，我们研究了不同条件下植被、水深和波浪特性之间的相互作用，包括不规则波浪的风暴情景。结果表明，在一个特定的阈值处，盐沼模型对能量的衰减效果最佳，而在极浅的水深处，波浪能量主要被贫瘠的前滩耗散。当波浪从深水传播到浅水深度时，由于波浪破碎和次重力波的产生，频谱波周期Tm−1,0增加。盐沼植被的存在通过优先抑制高频成分进一步增强了这种效果。这突出表明，在植被环境中，Tm−1,0的增加可能并不总是对应于堤防上水动力载荷的增加。

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引用次数: 0

Effectiveness of restored mangrove wetlands in damping waves 红树林湿地恢复后的减波效果

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-10-10 DOI: 10.1016/j.coastaleng.2025.104894

Zongyao Chen , Wen Wei , Xiufang Qiu , Yulu Yang , Heng Wang

There has been a global attention on the feasibility and embodiment of integrating the mangrove wetlands into coastal defense. However, little evidence is related to the restored mangroves (with mangrove trees artificially planted), which is increasingly important under ongoing wetland restoration worldwide. Here, wave propagation across a restored Kandelia obovata mangrove wetland on the Hailing Island, Guangdong Province, China, was observed to examine the wave damping effectiveness of the restored mangroves and their potential in coastal defense. The results showed that waves were attenuated by 26 % as they passed through the studied mangrove wetland. The wave attenuation rate of the bare flat was inversely proportional to water depth, and that of the mangrove forest was linked to its submerged state, peaking when the canopy was partially submerged. The restored mangrove attenuated waves more effectively than the bare flat, and showed reliable wave damping ability even in comparisons with natural marsh and mangrove vegetations. This evidence supports the feasibility of utilizing the restored mangroves in nature-based coastal defense. Furthermore, an idealized model was established to examine how the width of the restored mangrove impacts the gross wave attenuation. It is found that wave height reduction increases under a larger restored mangrove width, while the increase is nonlinear. We then proposed an optimal mangrove width proportion of 15 % for the studied wetland, under which the mangrove wetland showed a reliable gross wave height reduction together with a relatively large efficiency. These findings provide important insights into mangrove-induced wave attenuation and its implications for nature-based coastal defense worldwide.

将红树林湿地纳入海防的可行性和具体化一直是全球关注的问题。然而，与红树林的恢复（人工种植红树林）有关的证据很少，红树林在世界范围内正在进行的湿地恢复中越来越重要。在这里，我们观察了波浪在中国广东省海岭岛恢复后的红树湿地上的传播，以研究恢复后的红树湿地的波浪阻尼效果及其在海防中的潜力。结果表明，波浪在通过红树林湿地时衰减了26%。裸滩的波浪衰减率与水深成反比，红树林的波浪衰减率与其淹没状态有关，在冠层部分被淹没时达到峰值。恢复后的红树林比光秃秃的平地更有效地衰减波浪，即使与天然沼泽和红树林植被相比，也表现出可靠的减波能力。这一证据支持了利用恢复后的红树林进行自然海防的可行性。此外，还建立了一个理想化的模型来研究恢复红树林的宽度对总波衰减的影响。研究发现，红树林恢复宽度越大，波高减小幅度越大，但减小幅度是非线性的。在此基础上，我们提出了一个最优的红树林宽度比例为15%，在此条件下，红树林湿地呈现出可靠的总波高降低和相对较大的效率。这些发现为红树林引起的波浪衰减及其对全球自然海防的影响提供了重要的见解。

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引用次数: 0

Extreme wave conditions and Tropical Cyclone contributions based on high-resolution wave modeling 基于高分辨率波浪模拟的极端波浪条件和热带气旋贡献

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-11-19 DOI: 10.1016/j.coastaleng.2025.104913

Xingkun Xu , Kaushik Sasmal , Zunya Wang , Pavel Tkalich

Accurate estimation of extreme wave conditions and their long-term changes is essential for designing resilient coastal infrastructure in the South China Sea (SCS), where densely populated coastlines face frequent extreme weather events. Based on a nested, high-resolution WAVEWATCH III (WW3) hindcast driven by ERA5 winds (1979–2023), this study identifies spatially heterogeneous trends in significant wave height (

H_{s}

). Notably, the 99th percentile and annual maxima of

H_{s}

show pronounced increases exceeding 1.5 cm/year and 3.0 cm/year, respectively, in the central deep basin, with the most significant seasonal intensification occurring during boreal winter (DJF). To support long-term risk assessment and design, three extreme value analysis (EVA) approaches, GEV annual maxima (AM), GPD peak-over-threshold (POT), and GPD based on declustering (DC), are employed for a comprehensive estimation of extreme wave return levels spanning 10–100 years. While the GEV annual maxima (AM) method generally produces the highest return level estimates at typhoon-prone locations and the POT method yields more conservative values, the declustered (DC) approach provides a reasonable intermediate balance between the two. Specifically, the 100-year return levels estimated by GPD DC reach 8.25 m, 12.36 m, 9.69 m, and 8.40 m at four representative offshore sites (P1–P4), respectively. To assess coastal hazard relevance, a normalized risk index (

H_{s, 100 r p}

/mean

H_{s}

) highlights hotspots along the southeastern coast of Vietnam, the Beibu Gulf, and the Luzon Strait. Building on these spatial patterns, TC contributions are further investigated, representing that Tropical Cyclone–induced extremes dominate the northern SCS, the western Luzon Strait, and the southeastern coast of China, while other synoptic systems may possibly play a larger role in the southwestern regions of SCS.

对极端海浪条件及其长期变化的准确估计对于设计具有弹性的南海沿海基础设施至关重要，南海人口密集的海岸线面临频繁的极端天气事件。基于ERA5风驱动的高分辨率WAVEWATCH III （WW3）嵌套后播（1979-2023），本研究确定了显著波高（Hs）的空间异质性趋势。值得注意的是，在中部深盆地，Hs的第99个百分点和年最大值分别超过1.5 cm/年和3.0 cm/年，其中以寒带冬季（DJF）的季节性增强最为显著。为了支持长期风险评估和设计，采用了GEV年最大值（AM）、GPD超阈值峰值（POT）和基于聚类的GPD （DC）三种极值分析（EVA）方法，对10-100年的极端波回归水平进行了综合估计。GEV年极大值（AM）方法通常在台风易发地点产生最高的回归水平估计，而POT方法产生更保守的值，而散聚（DC）方法在两者之间提供了一个合理的中间平衡。具体而言，GPD DC估计的100年回归水平在四个代表性海上站点（P1-P4）分别达到8.25 m, 12.36 m， 9.69 m和8.40 m。为了评估沿海灾害的相关性，标准化风险指数（Hs，100rp/平均Hs）突出了越南东南沿海、北部湾和吕宋海峡的热点地区。在这些空间格局的基础上，进一步研究了TC的贡献，表明热带气旋引起的极端事件主要发生在南海北部、吕宋海峡西部和中国东南沿海，而其他天气系统可能在南海西南部地区发挥更大的作用。

{"title":"Extreme wave conditions and Tropical Cyclone contributions based on high-resolution wave modeling","authors":"Xingkun Xu , Kaushik Sasmal , Zunya Wang , Pavel Tkalich","doi":"10.1016/j.coastaleng.2025.104913","DOIUrl":"10.1016/j.coastaleng.2025.104913","url":null,"abstract":"<div><div>Accurate estimation of extreme wave conditions and their long-term changes is essential for designing resilient coastal infrastructure in the South China Sea (SCS), where densely populated coastlines face frequent extreme weather events. Based on a nested, high-resolution WAVEWATCH III (WW3) hindcast driven by ERA5 winds (1979–2023), this study identifies spatially heterogeneous trends in significant wave height (<span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>). Notably, the 99th percentile and annual maxima of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> show pronounced increases exceeding 1.5 cm/year and 3.0 cm/year, respectively, in the central deep basin, with the most significant seasonal intensification occurring during boreal winter (DJF). To support long-term risk assessment and design, three extreme value analysis (EVA) approaches, GEV annual maxima (AM), GPD peak-over-threshold (POT), and GPD based on declustering (DC), are employed for a comprehensive estimation of extreme wave return levels spanning 10–100 years. While the GEV annual maxima (AM) method generally produces the highest return level estimates at typhoon-prone locations and the POT method yields more conservative values, the declustered (DC) approach provides a reasonable intermediate balance between the two. Specifically, the 100-year return levels estimated by GPD DC reach 8.25 m, 12.36 m, 9.69 m, and 8.40 m at four representative offshore sites (P1–P4), respectively. To assess coastal hazard relevance, a normalized risk index (<span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi><mo>,</mo><mn>100</mn><mi>r</mi><mi>p</mi></mrow></msub></math></span>/mean <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>) highlights hotspots along the southeastern coast of Vietnam, the Beibu Gulf, and the Luzon Strait. Building on these spatial patterns, TC contributions are further investigated, representing that Tropical Cyclone–induced extremes dominate the northern SCS, the western Luzon Strait, and the southeastern coast of China, while other synoptic systems may possibly play a larger role in the southwestern regions of SCS.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"204 ","pages":"Article 104913"},"PeriodicalIF":4.5,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617900","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}

引用次数: 0

Effect of clay content on the coupled seabed response and local scour around a free-spanning pipeline under combined waves and currents 波浪和水流联合作用下粘土含量对自由跨管道周围海床响应和局部冲刷的影响

IF 4.5 2区工程技术 Q1 ENGINEERING, CIVIL

Coastal Engineering

Pub Date : 2026-01-30 Epub Date: 2025-11-13 DOI: 10.1016/j.coastaleng.2025.104910

Hongyi Zhao , Fei Lin , Yaru Gao , Zheng Wang , Mengxiao Li , Xiaoli Liu , Shuang Han , Dong-Sheng Jeng

Scour around submarine pipelines on a sand–clay mixed seabed under combined wave and current loading conditions involves complex interdisciplinary interactions among hydrodynamics, seabed mechanics and sediment transport processes. Although previous studies have addressed the scour or dynamic response of the seabed in isolation, their relationship remains unclear. This study performs laboratory experiments to clarify the integrated processes between local scour and seabed response around pipelines laid on a sand–clay mixed seabed with clay contents ranging from 5% to 20%. The results show that increasing the clay content enhances the dissipation of wave energy and reduces the dynamic pressure under high wave steepness, while simultaneously promoting tunnel scour beneath the pipeline due to cumulative pore pressure build-up. The phenomenon reduces the velocity and local pressure below a pipeline. Furthermore, the presence of clay shifts the maximum oscillatory pore pressures to intermediate depths and alters the residual pressure distributions depending on the extent of the scour. Although upward seepage induced by residual pore pressure in clay-rich seabeds has limited influence on wave-induced shear stress, it plays a critical role in reducing the threshold for sediment initiation, accelerating early-stage scour and increasing suspended sediment concentration (SSC), particularly under large wave steepness (that is,

H / L_{0}

=

0.052). At smaller wave steepness (that is,

H / L_{0}

=

0.018), an addition of 5% clay enhances SSC and promotes scour, while a higher clay content suppresses sediment mobility, where seepage induced by oscillatory pore pressure may play a significant role. An empirical formula incorporating clay content, the Keulegan–Carpenter (KC) number, and the Shields parameter is proposed to support engineering design in mixed sand–clay seabed conditions.

波浪和水流联合作用下的砂-粘土混合海底管道冲刷是水力学、海底力学和输沙过程相互作用的复杂学科。虽然以前的研究孤立地处理了海床的冲刷或动力反应，但它们之间的关系仍不清楚。在粘土含量为5% ~ 20%的砂-粘土混合海床上铺设管道，通过室内实验，阐明管道周围局部冲刷与海底响应的综合过程。结果表明：在高波浪陡度条件下，增加粘土含量可增强波浪能的耗散，降低动压，同时由于累积孔隙压力的积聚，促进管道下方隧道冲刷；这种现象降低了管道下方的速度和局部压力。此外，粘土的存在将最大振荡孔隙压力移至中间深度，并根据冲刷程度改变残余压力分布。虽然富粘土海床中残余孔隙压力引起的向上渗流对波浪剪切应力的影响有限，但在降低起沙阈值、加速早期冲刷和增加悬沙浓度（SSC）方面具有关键作用，特别是在大波浪陡度（即H/L0 = 0.052）下。当波浪陡度较小（H/L0 = 0.018）时，掺5%粘土增强了SSC，促进了冲刷，而掺5%粘土抑制了沉积物的流动性，其中振荡孔压诱发的渗流可能起重要作用。提出了结合粘土含量、Keulegan-Carpenter （KC）数和Shields参数的经验公式，以支持砂-粘土混合海底条件下的工程设计。

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引用次数: 0