Pub Date : 2026-02-06DOI: 10.1016/j.oceaneng.2026.124565
Yaohui Qiang , Yanchong Duan , Liekai Cao , Dejun Zhu , Jian Jiao , Lei Ding , Xiping Dou , Danxun Li
Selecting an efficient operational mode for air-jet seabed scouring requires understanding how jet expansion state governs both mechanism and performance. This study experimentally compares under-expanded and fully expanded air jets impinging on a non-cohesive sand bed in quiescent water. High-speed imaging reveals two distinct mechanisms: the expanded jet drives continuous viscous shear erosion (VSE), reaching dynamic equilibrium rapidly (0.48-3.9 s) via stable wall-bounded shear flow, whereas the under-expanded jet triggers violent bearing-capacity failure (BCF), requiring significantly longer times (5.9-7.0 s) due to intermittent explosive ejections. Under identical flow input, the expanded jet demonstrated unequivocally superior performance, achieving an 11-24% increase in maximum particle entrainment height, an expansion of cumulative entrainment area by up to 1.9 times, and a remarkable enhancement of the horizontal diffusion rate by a factor of 3.9 to 7.9. Morphologically, its scour profile closely matches the classical shear-driven model (R2 = 0.98), while the under-expanded jet yields a concave, non-classical profile (R2 = 0.63) with limited downstream transport. The jet expansion state, controlled by standoff distance relative to the Mach disk, thus governs the transition between efficient shear dominated and inefficient explosion dominated regimes, providing a quantitative basis for selecting the fully expanded mode in seabed trenching and similar marine engineering applications.
{"title":"Scour mechanism and efficiency contrast between under-expanded and expanded air jets in underwater","authors":"Yaohui Qiang , Yanchong Duan , Liekai Cao , Dejun Zhu , Jian Jiao , Lei Ding , Xiping Dou , Danxun Li","doi":"10.1016/j.oceaneng.2026.124565","DOIUrl":"10.1016/j.oceaneng.2026.124565","url":null,"abstract":"<div><div>Selecting an efficient operational mode for air-jet seabed scouring requires understanding how jet expansion state governs both mechanism and performance. This study experimentally compares under-expanded and fully expanded air jets impinging on a non-cohesive sand bed in quiescent water. High-speed imaging reveals two distinct mechanisms: the expanded jet drives continuous viscous shear erosion (VSE), reaching dynamic equilibrium rapidly (0.48-3.9 s) via stable wall-bounded shear flow, whereas the under-expanded jet triggers violent bearing-capacity failure (BCF), requiring significantly longer times (5.9-7.0 s) due to intermittent explosive ejections. Under identical flow input, the expanded jet demonstrated unequivocally superior performance, achieving an 11-24% increase in maximum particle entrainment height, an expansion of cumulative entrainment area by up to 1.9 times, and a remarkable enhancement of the horizontal diffusion rate by a factor of 3.9 to 7.9. Morphologically, its scour profile closely matches the classical shear-driven model (<em>R</em><sup>2</sup> = 0.98), while the under-expanded jet yields a concave, non-classical profile (<em>R</em><sup>2</sup> = 0.63) with limited downstream transport. The jet expansion state, controlled by standoff distance relative to the Mach disk, thus governs the transition between efficient shear dominated and inefficient explosion dominated regimes, providing a quantitative basis for selecting the fully expanded mode in seabed trenching and similar marine engineering applications.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124565"},"PeriodicalIF":5.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192637","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 : 2026-02-06DOI: 10.1016/j.oceaneng.2026.124533
Xudong Ye , Xiaoqiang Yang , Wei Fan , Mindong Yang , Kaiming Bi
With the rapid development of offshore wind industry, the collision between ships and floating offshore wind turbines (FOWTs) has emerged as a substantial concern. However, research on this topic remains scarce. To address this gap, this study carries out refined finite element (FE) analyses to investigate the dynamic responses of operational FOWTs subjected to ship collisions. A 3000 DWT carrier with a mass of 4000 tons is selected as the striking object. Aerodynamic and hydrodynamic effects are incorporated via a coupled procedure. The model is validated by comparing its results with previous studies and benchmarks. Key parameters, including impact velocity, plate thickness, wind direction, and wind velocity, are examined to assess their influence on collision dynamics. Results reveal a multi-phase collision process between the ship and FOWT, with energy predominantly exchanged in the primary collision phase. Distinct collision modes and structural damage under varying impact velocities and plate thicknesses are observed. Damage to both the ship and FOWT correlates with wind direction, whereas wind velocity has a limited effect on the dynamic responses of the FOWT. These findings provide valuable insights into the collision behavior of FOWTs, contributing to their design and safety assessment in offshore environments.
{"title":"Dynamic behaviors of operational floating offshore wind turbines subjected to ship collisions","authors":"Xudong Ye , Xiaoqiang Yang , Wei Fan , Mindong Yang , Kaiming Bi","doi":"10.1016/j.oceaneng.2026.124533","DOIUrl":"10.1016/j.oceaneng.2026.124533","url":null,"abstract":"<div><div>With the rapid development of offshore wind industry, the collision between ships and floating offshore wind turbines (FOWTs) has emerged as a substantial concern. However, research on this topic remains scarce. To address this gap, this study carries out refined finite element (FE) analyses to investigate the dynamic responses of operational FOWTs subjected to ship collisions. A 3000 DWT carrier with a mass of 4000 tons is selected as the striking object. Aerodynamic and hydrodynamic effects are incorporated via a coupled procedure. The model is validated by comparing its results with previous studies and benchmarks. Key parameters, including impact velocity, plate thickness, wind direction, and wind velocity, are examined to assess their influence on collision dynamics. Results reveal a multi-phase collision process between the ship and FOWT, with energy predominantly exchanged in the primary collision phase. Distinct collision modes and structural damage under varying impact velocities and plate thicknesses are observed. Damage to both the ship and FOWT correlates with wind direction, whereas wind velocity has a limited effect on the dynamic responses of the FOWT. These findings provide valuable insights into the collision behavior of FOWTs, contributing to their design and safety assessment in offshore environments.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124533"},"PeriodicalIF":5.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192630","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 : 2026-02-06DOI: 10.1016/j.oceaneng.2026.124457
Basma Refaat Habeeb , Moustafa Abdel-Maksoud
Offshore aquaculture faces a critical challenge in securing a sustainable and reliable power supply due to its increasing energy demands. Ensuring both structural compatibility and efficient energy generation remains a significant barrier. The rigid geometry of floating aquaculture cage structure permits the installation of multiple Oscillating Water Column Wave Energy Converters (OWC–WECs) along their perimeter, thereby enhancing energy capture through array configurations. This study presents a numerical investigation of OWC–WEC arrays integrated with a floating aquaculture cage. A three-dimensional RANS–VOF framework, incorporating an advanced forcing-zone method and finite-volume discretization, was developed to evaluate the hydrodynamic performance of the hybrid system under regular and irregular waves. Convergence analyses were carried out, and the numerical model was validated against available experimental data, demonstrating good agreement. Using this validated framework, a systematic evaluation of different array layouts was performed to examine the influence of device quantity and spatial arrangement on system performance. Both single- and dual-chamber configurations, positioned adjacent to the aquaculture cage, were simulated to assess pneumatic power output and platform motion response. The influence of mooring pretension was also investigated, highlighting its combined effect with array configuration on optimizing energy performance. Overall, the findings establish a structured methodology for assessing and optimizing hybrid marine systems that integrate sustainable aquaculture with wave energy harvesting.
{"title":"Hydrodynamic performance of oscillating water column wave energy converter arrays of offshore hybrid aquaculture–energy platforms","authors":"Basma Refaat Habeeb , Moustafa Abdel-Maksoud","doi":"10.1016/j.oceaneng.2026.124457","DOIUrl":"10.1016/j.oceaneng.2026.124457","url":null,"abstract":"<div><div>Offshore aquaculture faces a critical challenge in securing a sustainable and reliable power supply due to its increasing energy demands. Ensuring both structural compatibility and efficient energy generation remains a significant barrier. The rigid geometry of floating aquaculture cage structure permits the installation of multiple <strong>O</strong>scillating <strong>W</strong>ater <strong>C</strong>olumn <strong>W</strong>ave <strong>E</strong>nergy <strong>C</strong>onverters (OWC–WECs) along their perimeter, thereby enhancing energy capture through array configurations. This study presents a numerical investigation of OWC–WEC arrays integrated with a floating aquaculture cage. A three-dimensional RANS–VOF framework, incorporating an advanced forcing-zone method and finite-volume discretization, was developed to evaluate the hydrodynamic performance of the hybrid system under regular and irregular waves. Convergence analyses were carried out, and the numerical model was validated against available experimental data, demonstrating good agreement. Using this validated framework, a systematic evaluation of different array layouts was performed to examine the influence of device quantity and spatial arrangement on system performance. Both single- and dual-chamber configurations, positioned adjacent to the aquaculture cage, were simulated to assess pneumatic power output and platform motion response. The influence of mooring pretension was also investigated, highlighting its combined effect with array configuration on optimizing energy performance. Overall, the findings establish a structured methodology for assessing and optimizing hybrid marine systems that integrate sustainable aquaculture with wave energy harvesting.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124457"},"PeriodicalIF":5.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192638","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 : 2026-02-06DOI: 10.1016/j.oceaneng.2026.124520
Ye Tang , Shengju Li , Su Jia , Yang Bu , Tianzhi Yang
Vibrations in marine piping systems induced by internal and external excitations can lead to fatigue damage of the pipes or supporting structures and contribute to noise transmission. This study proposes a novel vibration suppression strategy for marine fluid-conveying pipeline systems by harnessing the synergistic integration of the acoustic black hole effect and phononic crystal theory. A fluid-structure interaction model based on the 14-equation pipeline formulation is established and solved using the spectral element method, enabling accurate dynamic analysis of straight and L-shaped pipeline meta structures with continuous configuration variations. Results show that periodic acoustic black hole designs create well-defined band gaps that effectively suppress bending and torsional vibrations, which is the dominant energy transmission mechanisms in pipelines. Comparative analysis indicates that L-shaped pipes promote vibration localization at elevated frequencies, resulting in improved vibration reduction performance compared to uniform-diameter counterparts. Parametric studies further identify key geometric influences on bandgap behavior, including lattice length, power-law exponent, and diameter adjustments. This study presents a novel vibration suppression technology for marine pipelines featuring complex spatial configurations, offering a promising solution for effective structural vibration control in practical engineering applications.
{"title":"Vibration suppression of L-shaped pipelines conveying fluid based on multi-directional bandgap generation","authors":"Ye Tang , Shengju Li , Su Jia , Yang Bu , Tianzhi Yang","doi":"10.1016/j.oceaneng.2026.124520","DOIUrl":"10.1016/j.oceaneng.2026.124520","url":null,"abstract":"<div><div>Vibrations in marine piping systems induced by internal and external excitations can lead to fatigue damage of the pipes or supporting structures and contribute to noise transmission. This study proposes a novel vibration suppression strategy for marine fluid-conveying pipeline systems by harnessing the synergistic integration of the acoustic black hole effect and phononic crystal theory. A fluid-structure interaction model based on the 14-equation pipeline formulation is established and solved using the spectral element method, enabling accurate dynamic analysis of straight and L-shaped pipeline meta structures with continuous configuration variations. Results show that periodic acoustic black hole designs create well-defined band gaps that effectively suppress bending and torsional vibrations, which is the dominant energy transmission mechanisms in pipelines. Comparative analysis indicates that L-shaped pipes promote vibration localization at elevated frequencies, resulting in improved vibration reduction performance compared to uniform-diameter counterparts. Parametric studies further identify key geometric influences on bandgap behavior, including lattice length, power-law exponent, and diameter adjustments. This study presents a novel vibration suppression technology for marine pipelines featuring complex spatial configurations, offering a promising solution for effective structural vibration control in practical engineering applications.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124520"},"PeriodicalIF":5.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192632","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 : 2026-02-06DOI: 10.1016/j.oceaneng.2026.124507
Xiaolong Yao , Kelin Feng , Kewen Li , Yongming Li , Yu Wang , Xuejian Bai , Wenxing Sun , Yazhou Fan , Zheng Wang , Guohai Lin
This paper investigates the path-following control problem with obstacle avoidance for an underwater tracked robot (UTR) under path-dependent constraints. Fuzzy logic systems (FLSs) are utilized to approximate the unknown nonlinear dynamics in the system model. Then the performance functions are constructed via the path parameter to ensure that the prescribed performance constraints are satisfied during the obstacle avoidance process. To reduce the computational complexity of the control design, the dynamic surface control (DSC) technique is introduced in control design. Subsequently, under the framework of backstepping design, an adaptive fuzzy path-following control scheme with obstacle avoidance is developed by integrating the constructed logarithmic barrier function (LBF). The proposed control scheme not only guarantees constraint satisfaction in the presence of multiple obstacles, but also ensures the boundedness of all UTR signals. Finally, comparative simulation results are provided to demonstrate the effectiveness of the proposed control algorithm.
{"title":"Obstacle avoidance path tracking control for underwater tracked robots with path-dependent constraints","authors":"Xiaolong Yao , Kelin Feng , Kewen Li , Yongming Li , Yu Wang , Xuejian Bai , Wenxing Sun , Yazhou Fan , Zheng Wang , Guohai Lin","doi":"10.1016/j.oceaneng.2026.124507","DOIUrl":"10.1016/j.oceaneng.2026.124507","url":null,"abstract":"<div><div>This paper investigates the path-following control problem with obstacle avoidance for an underwater tracked robot (UTR) under path-dependent constraints. Fuzzy logic systems (FLSs) are utilized to approximate the unknown nonlinear dynamics in the system model. Then the performance functions are constructed via the path parameter to ensure that the prescribed performance constraints are satisfied during the obstacle avoidance process. To reduce the computational complexity of the control design, the dynamic surface control (DSC) technique is introduced in control design. Subsequently, under the framework of backstepping design, an adaptive fuzzy path-following control scheme with obstacle avoidance is developed by integrating the constructed logarithmic barrier function (LBF). The proposed control scheme not only guarantees constraint satisfaction in the presence of multiple obstacles, but also ensures the boundedness of all UTR signals. Finally, comparative simulation results are provided to demonstrate the effectiveness of the proposed control algorithm.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124507"},"PeriodicalIF":5.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192636","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 : 2026-02-06DOI: 10.1016/j.oceaneng.2026.124475
Mastaneh Moattari , Franziska Schmidt , Clemens Hübler , Daniel Ribnitzky , Raimund Rolfes , Elyas Ghafoori
Offshore jacket structures play a key role in renewable energy by supporting offshore wind turbines (OWTs). This study presents the development and application of advanced meta-models for efficient prediction of fatigue damage in jacket joints of 25 MW OWTs. Although meta-models have become state-of-the-art for fatigue assessment of conventional OWTs (typically 5–15 MW), there remains a need to validate their applicability to next-generation turbines with mega structures and capacities over 20 MW. For the first time, in this study, the performance of such meta-models has been tested and validated using data generated within a systematic framework. This addresses a critical knowledge gap as the industry transitions to unprecedented turbine capacities. The investigation focused on two representative joints: the most critical and the mudline joints. The integration of aeroelastic, hydrodynamic, and soil-structure interactions within a methodological framework enables the training of Kriging-based meta-models on high-fidelity simulation data, ensuring rapid and accurate predictions. A parametric analysis is conducted with respect to key environmental drivers, including wind speed, significant wave height, peak period, turbulence intensity, and wind–wave misalignment. The predictive performance validation demonstrates the effectiveness of meta-models even at these large scales. A rigorous benchmark against an established 5 MW OWT meta-model reveals pronounced scaling effects. The results indicate that as the turbine size increases, the wave-induced loading becomes the predominant fatigue driver for the jacket, surpassing wind speed effects. This challenges existing design assumptions for large-scale turbine jackets. The findings of this study represent a significant advancement, as they demonstrate, for the first time, the potential of meta-models to facilitate rapid, data-driven fatigue assessments of offshore mega-jacket designs. This advancement paves the way for enhanced reliability and efficiency in jacket design, optimization, and operational monitoring for future high-capacity wind turbines.
{"title":"Meta-model-based fatigue analysis of 25 MW offshore jackets: relevance of wind and wave conditions","authors":"Mastaneh Moattari , Franziska Schmidt , Clemens Hübler , Daniel Ribnitzky , Raimund Rolfes , Elyas Ghafoori","doi":"10.1016/j.oceaneng.2026.124475","DOIUrl":"10.1016/j.oceaneng.2026.124475","url":null,"abstract":"<div><div>Offshore jacket structures play a key role in renewable energy by supporting offshore wind turbines (OWTs). This study presents the development and application of advanced meta-models for efficient prediction of fatigue damage in jacket joints of 25 MW OWTs. Although meta-models have become state-of-the-art for fatigue assessment of conventional OWTs (typically 5–15 MW), there remains a need to validate their applicability to next-generation turbines with mega structures and capacities over 20 MW. For the first time, in this study, the performance of such meta-models has been tested and validated using data generated within a systematic framework. This addresses a critical knowledge gap as the industry transitions to unprecedented turbine capacities. The investigation focused on two representative joints: the most critical and the mudline joints. The integration of aeroelastic, hydrodynamic, and soil-structure interactions within a methodological framework enables the training of Kriging-based meta-models on high-fidelity simulation data, ensuring rapid and accurate predictions. A parametric analysis is conducted with respect to key environmental drivers, including wind speed, significant wave height, peak period, turbulence intensity, and wind–wave misalignment. The predictive performance validation demonstrates the effectiveness of meta-models even at these large scales. A rigorous benchmark against an established 5 MW OWT meta-model reveals pronounced scaling effects. The results indicate that as the turbine size increases, the wave-induced loading becomes the predominant fatigue driver for the jacket, surpassing wind speed effects. This challenges existing design assumptions for large-scale turbine jackets. The findings of this study represent a significant advancement, as they demonstrate, for the first time, the potential of meta-models to facilitate rapid, data-driven fatigue assessments of offshore mega-jacket designs. This advancement paves the way for enhanced reliability and efficiency in jacket design, optimization, and operational monitoring for future high-capacity wind turbines.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124475"},"PeriodicalIF":5.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192640","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 : 2026-02-05DOI: 10.1016/j.oceaneng.2026.124406
Kaiwei Xu , Jiaqi Luo , Jiaming Zhao , Danda Shi , Zhiming Chao , Titi Sui
Marine coral clay, a critical fine-grained component in reclaimed island foundations for ocean engineering, is typically mixed with marine coral sand to form composite foundation soil that governs offshore infrastructure stability. To address accurate strength prediction of this soil reinforced by 3D-printed bionic honeycomb polymer grid (BHPG), this study develops a CNN-LSTM model, uses SHapley Additive exPlanations (SHAP) to quantify input parameter importance, and validates it with 1200 triaxial shear tests. Results confirm high accuracy and identify reinforcement type, layers, and confining pressure as key factors, while a derived empirical formula enables rapid engineering use. A user-friendly graphical user interface (GUI) is also developed for ocean engineering practitioners to get real-time strength predictions. This work reduces test costs, advances deep learning-marine engineering integration, and supports BHPG application in reclaimed islands and offshore platforms.
{"title":"Mechanical behavior of marine coral sand - coral clay mixtures reinforced with bionic honeycomb polymer grid: Experimental and artificial intelligence methods","authors":"Kaiwei Xu , Jiaqi Luo , Jiaming Zhao , Danda Shi , Zhiming Chao , Titi Sui","doi":"10.1016/j.oceaneng.2026.124406","DOIUrl":"10.1016/j.oceaneng.2026.124406","url":null,"abstract":"<div><div>Marine coral clay, a critical fine-grained component in reclaimed island foundations for ocean engineering, is typically mixed with marine coral sand to form composite foundation soil that governs offshore infrastructure stability. To address accurate strength prediction of this soil reinforced by 3D-printed bionic honeycomb polymer grid (BHPG), this study develops a CNN-LSTM model, uses SHapley Additive exPlanations (SHAP) to quantify input parameter importance, and validates it with 1200 triaxial shear tests. Results confirm high accuracy and identify reinforcement type, layers, and confining pressure as key factors, while a derived empirical formula enables rapid engineering use. A user-friendly graphical user interface (GUI) is also developed for ocean engineering practitioners to get real-time strength predictions. This work reduces test costs, advances deep learning-marine engineering integration, and supports BHPG application in reclaimed islands and offshore platforms.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124406"},"PeriodicalIF":5.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116758","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 : 2026-02-05DOI: 10.1016/j.oceaneng.2026.124525
Huipeng Jiang , Qiang Ma
Submarine permafrost occurs in shallow cold-region shelves, where seismic shaking may threaten offshore infrastructure. This study derives an analytical free-field solution for a coupled seawater-frozen seabed-bedrock system subjected to obliquely incident plane SV waves. Seawater is modelled as an inviscid compressible acoustic layer, the frozen seabed as a frozen saturated three-phase porous medium described by LCAM (Linearised Contact-Adhesion Model), and the bedrock as an elastic half-space. Using Helmholtz-decomposed potentials, Snell's law, and the transmission-reflection (T-R) method, closed-form frequency-domain displacements are obtained, capturing P-SV mode conversion within the frozen layer. Dimensionless horizontal and vertical surface-to-base transfer functions are defined, and pulse-excited time histories are reconstructed via inverse FFT. The solution is verified against published benchmark results for coupled seawater-seabed-bedrock systems. Parametric analyses examine temperature, porosity, incident angle, cementation-related Poisson's ratio, ice-skeleton contact condition, and depth. Results show that both the overlying seawater and the incident angle strongly reshape the transfer functions, with the vertical response particularly sensitive to fluid-solid coupling and interference/mode conversion. Lower temperatures reduce displacements and shift dominant peaks to higher frequencies, whereas higher porosity and weaker inter-phase constraint increase amplification. The formulation provides efficient baseline motions for subsequent seawater-frozen seabed-structure interaction analyses at laterally uniform sites.
{"title":"Free-field response of a seawater-frozen seabed system under obliquely incident SV waves","authors":"Huipeng Jiang , Qiang Ma","doi":"10.1016/j.oceaneng.2026.124525","DOIUrl":"10.1016/j.oceaneng.2026.124525","url":null,"abstract":"<div><div>Submarine permafrost occurs in shallow cold-region shelves, where seismic shaking may threaten offshore infrastructure. This study derives an analytical free-field solution for a coupled seawater-frozen seabed-bedrock system subjected to obliquely incident plane SV waves. Seawater is modelled as an inviscid compressible acoustic layer, the frozen seabed as a frozen saturated three-phase porous medium described by LCAM (Linearised Contact-Adhesion Model), and the bedrock as an elastic half-space. Using Helmholtz-decomposed potentials, Snell's law, and the transmission-reflection (T-R) method, closed-form frequency-domain displacements are obtained, capturing P-SV mode conversion within the frozen layer. Dimensionless horizontal and vertical surface-to-base transfer functions are defined, and pulse-excited time histories are reconstructed via inverse FFT. The solution is verified against published benchmark results for coupled seawater-seabed-bedrock systems. Parametric analyses examine temperature, porosity, incident angle, cementation-related Poisson's ratio, ice-skeleton contact condition, and depth. Results show that both the overlying seawater and the incident angle strongly reshape the transfer functions, with the vertical response particularly sensitive to fluid-solid coupling and interference/mode conversion. Lower temperatures reduce displacements and shift dominant peaks to higher frequencies, whereas higher porosity and weaker inter-phase constraint increase amplification. The formulation provides efficient baseline motions for subsequent seawater-frozen seabed-structure interaction analyses at laterally uniform sites.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124525"},"PeriodicalIF":5.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116760","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 : 2026-02-05DOI: 10.1016/j.oceaneng.2026.124515
Zishun Yao , Hao Hu , Wenlong Lu , Yinuo Chu , Yanhong Wang , Dawei Guan
Jacket foundations, prevalent in offshore wind installations, face local scour threats during service life. While existing studies have experimentally and numerically investigated local scour and flow fields around such foundations, research correlating flow characteristics with local scour under varying attack angles remains scarce. This study employed test conditions and scour bathymetries from previous flume tests, aims to employ numerical modeling to examine flow-structure interactions around jacket foundations subjected to four flow attack angles (0°, 15°, 30°, 45°). Results demonstrate equilibrium scour volumes around jacket foundations increase by 70.8% (15°), 76.8% (30°), and 28.0% (45°) relative to 0° due to varying sheltering effects at different attack angles. The flow intensities at the front piles of the jacket foundation remain consistent across different attack angles, whereas the sheltering effect reduces flow intensity at the rear piles. Equilibrium scour depths at rear piles decrease under 0° and 45° angles owing to sheltering effects, but increase under 15° and 30° angles due to contracted flow, demonstrating a strong correlation between equilibrium scour depth and flow intensity at rear piles. A dimensionless sheltering coefficient () is proposed to correlate with total scour volumes () at the jacket foundation, establishing a strong linear relationship. For engineering practice, alignment with dominant flow direction proves advantageous for scour protection and cost reduction for jacket foundations.
{"title":"Numerical investigation of flow patterns and sheltering effects around jacket foundations under varying attack angles","authors":"Zishun Yao , Hao Hu , Wenlong Lu , Yinuo Chu , Yanhong Wang , Dawei Guan","doi":"10.1016/j.oceaneng.2026.124515","DOIUrl":"10.1016/j.oceaneng.2026.124515","url":null,"abstract":"<div><div>Jacket foundations, prevalent in offshore wind installations, face local scour threats during service life. While existing studies have experimentally and numerically investigated local scour and flow fields around such foundations, research correlating flow characteristics with local scour under varying attack angles remains scarce. This study employed test conditions and scour bathymetries from previous flume tests, aims to employ numerical modeling to examine flow-structure interactions around jacket foundations subjected to four flow attack angles (0°, 15°, 30°, 45°). Results demonstrate equilibrium scour volumes around jacket foundations increase by 70.8% (15°), 76.8% (30°), and 28.0% (45°) relative to 0° due to varying sheltering effects at different attack angles. The flow intensities at the front piles of the jacket foundation remain consistent across different attack angles, whereas the sheltering effect reduces flow intensity at the rear piles. Equilibrium scour depths at rear piles decrease under 0° and 45° angles owing to sheltering effects, but increase under 15° and 30° angles due to contracted flow, demonstrating a strong correlation between equilibrium scour depth and flow intensity at rear piles. A dimensionless sheltering coefficient (<span><math><mrow><msub><mi>C</mi><mrow><mi>s</mi><mi>h</mi></mrow></msub></mrow></math></span>) is proposed to correlate with total scour volumes (<span><math><mrow><msub><mi>V</mi><mi>s</mi></msub><mo>/</mo><msup><mi>D</mi><mn>3</mn></msup></mrow></math></span>) at the jacket foundation, establishing a strong linear relationship. For engineering practice, alignment with dominant flow direction proves advantageous for scour protection and cost reduction for jacket foundations.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124515"},"PeriodicalIF":5.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116648","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 : 2026-02-05DOI: 10.1016/j.oceaneng.2026.124433
Xiaopeng Yang , Zhi Zong , Zhe Sun , Minghao Guo
To investigate the impact of structural deformation on the interaction between ice and structures, a small-scale indentation test was executed in a low temperature laboratory, utilizing elastic plates and frozen ice. The experiment primarily concentrated on the effect of structural stiffness on the interaction process at various velocities. Three strain rates, corresponding to the ductile and brittle failure modes of ice, were chosen. The compression stiffness ratio of the elastic plates to the ice sample was a critical variable, encompassing the influence of six distinct stiffness scenarios. Test results indicate that structural deformation modifies the relative velocity at which the structure penetrates into the ice and alters the distribution of high-pressure zones on the contact surface. Changes in structural stiffness impact both the location and extent of these high-pressure zones, resulting in shifts in ice failure modes and, subsequently, affecting the magnitude of the load. The nominal peak pressure tends to rise with greater structural stiffness but decreases with faster loading rates. The effect of variations in the relative interaction rates between ice and structure, caused by deformation, on the load magnitude appears to be less pronounced than that resulting from changes in contact position and area induced by deformation.
{"title":"An experimental study of interaction process between sea ice and variable stiffness elastic plates at various speeds","authors":"Xiaopeng Yang , Zhi Zong , Zhe Sun , Minghao Guo","doi":"10.1016/j.oceaneng.2026.124433","DOIUrl":"10.1016/j.oceaneng.2026.124433","url":null,"abstract":"<div><div>To investigate the impact of structural deformation on the interaction between ice and structures, a small-scale indentation test was executed in a low temperature laboratory, utilizing elastic plates and frozen ice. The experiment primarily concentrated on the effect of structural stiffness on the interaction process at various velocities. Three strain rates, corresponding to the ductile and brittle failure modes of ice, were chosen. The compression stiffness ratio of the elastic plates to the ice sample was a critical variable, encompassing the influence of six distinct stiffness scenarios. Test results indicate that structural deformation modifies the relative velocity at which the structure penetrates into the ice and alters the distribution of high-pressure zones on the contact surface. Changes in structural stiffness impact both the location and extent of these high-pressure zones, resulting in shifts in ice failure modes and, subsequently, affecting the magnitude of the load. The nominal peak pressure tends to rise with greater structural stiffness but decreases with faster loading rates. The effect of variations in the relative interaction rates between ice and structure, caused by deformation, on the load magnitude appears to be less pronounced than that resulting from changes in contact position and area induced by deformation.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"352 ","pages":"Article 124433"},"PeriodicalIF":5.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116652","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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