Current Articles
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2026, 40(1)
:1-14.
doi: 10.1007/s13344-026-0018-0
Abstract:
Structure-ice interaction problems have attracted increasing attention, yet accurately predicting the loads exerted by sea ice on ship hulls remains a significant challenge. Over the past few decades, various numerical methods have been employed to simulate ice resistance on ships and evaluate their manoeuvrability during ice-structure interaction. Among these approaches, the circumferential crack method has demonstrated both high efficiency and accuracy. This paper provides a detailed introduction to the fundamental theory of this method, including the numerical modeling of different failure modes and the dynamic ice motion responses. Furthermore, it reviews existing studies on predicting ice resistance and assessing the manoeuvrability of icebreakers navigating through ice-covered regions using the circumferential crack method. Several recommendations for future research in this field are also presented.
Structure-ice interaction problems have attracted increasing attention, yet accurately predicting the loads exerted by sea ice on ship hulls remains a significant challenge. Over the past few decades, various numerical methods have been employed to simulate ice resistance on ships and evaluate their manoeuvrability during ice-structure interaction. Among these approaches, the circumferential crack method has demonstrated both high efficiency and accuracy. This paper provides a detailed introduction to the fundamental theory of this method, including the numerical modeling of different failure modes and the dynamic ice motion responses. Furthermore, it reviews existing studies on predicting ice resistance and assessing the manoeuvrability of icebreakers navigating through ice-covered regions using the circumferential crack method. Several recommendations for future research in this field are also presented.
2026, 40(1)
:15-26.
doi: 10.1007/s13344-026-0001-9
Abstract:
This study presents a systematic investigation of tsunami resonance characteristics in the Pearl River Estuary and examines the influence of solitary waves with varying wave heights on the regional coastline. The research employed an extended mild-slope equation (EMSE) model in the frequency domain to determine eigenperiods and corresponding resonant modal shapes for the Pearl River Estuary, with the frequency-domain simulation results validated through FFT analysis. The FUNWAVE-total variation diminishing (TVD) model was subsequently applied to simulate the propagation, evolution, and run-up processes of solitary waves with different incident wave heights along the estuary coastline. Analysis revealed that within the studied range of incident wave heights and periods, the maximum and minimum periods were 120 min and 49 min, respectively. The most intense oscillations occurred at resonant modes corresponding to periods of 120 min and 63 min. The time-domain eigenperiods of 90 min, 68 min, and 49 min demonstrated strong correlation with the frequency-domain results of 92 min, 68 min, and 49 min. The outer island chain exhibited a significant blocking effect, resulting in wave run-up concentration at the estuary mouth, with limited energy propagation into the inner estuary regions.
This study presents a systematic investigation of tsunami resonance characteristics in the Pearl River Estuary and examines the influence of solitary waves with varying wave heights on the regional coastline. The research employed an extended mild-slope equation (EMSE) model in the frequency domain to determine eigenperiods and corresponding resonant modal shapes for the Pearl River Estuary, with the frequency-domain simulation results validated through FFT analysis. The FUNWAVE-total variation diminishing (TVD) model was subsequently applied to simulate the propagation, evolution, and run-up processes of solitary waves with different incident wave heights along the estuary coastline. Analysis revealed that within the studied range of incident wave heights and periods, the maximum and minimum periods were 120 min and 49 min, respectively. The most intense oscillations occurred at resonant modes corresponding to periods of 120 min and 63 min. The time-domain eigenperiods of 90 min, 68 min, and 49 min demonstrated strong correlation with the frequency-domain results of 92 min, 68 min, and 49 min. The outer island chain exhibited a significant blocking effect, resulting in wave run-up concentration at the estuary mouth, with limited energy propagation into the inner estuary regions.
2026, 40(1)
:27-38.
doi: 10.1007/s13344-026-0002-8
Abstract:
Based on the focusing principle of the Luneburg lens in optics, a water depth expression for Luneburg lens topography was derived using the linear ray method. This topography functions as a “perfect” focusing terrain, directing all wave rays to converge at a specific point. An analytical solution for long-wave propagation over Luneburg lens topography was developed and validated using Longuet-Higgins’s analytical solution for a submerged cylinder. Through this analytical solution, the long-wave focusing mechanism over the Luneburg lens topography was systematically examined under various water depths, incident wave periods, and terrain bottom radii. The analysis revealed that the wave-focusing effect intensifies with decreasing incident wave period and water depth, and increasing terrain bottom radius. The relative scale of terrain (kr0) emerges as a crucial parameter affecting wave focusing. As k0r0 increases, the wave-focusing effect initially intensifies before reaching stability. Furthermore, quantitative relationships were established between the maximum wave surface and its location generated by long-wave focusing over Luneburg lens topography and the relative terrain scale. Formulas for calculating the focusing wave height and focusing location were developed under linear long-wave conditions.
Based on the focusing principle of the Luneburg lens in optics, a water depth expression for Luneburg lens topography was derived using the linear ray method. This topography functions as a “perfect” focusing terrain, directing all wave rays to converge at a specific point. An analytical solution for long-wave propagation over Luneburg lens topography was developed and validated using Longuet-Higgins’s analytical solution for a submerged cylinder. Through this analytical solution, the long-wave focusing mechanism over the Luneburg lens topography was systematically examined under various water depths, incident wave periods, and terrain bottom radii. The analysis revealed that the wave-focusing effect intensifies with decreasing incident wave period and water depth, and increasing terrain bottom radius. The relative scale of terrain (kr0) emerges as a crucial parameter affecting wave focusing. As k0r0 increases, the wave-focusing effect initially intensifies before reaching stability. Furthermore, quantitative relationships were established between the maximum wave surface and its location generated by long-wave focusing over Luneburg lens topography and the relative terrain scale. Formulas for calculating the focusing wave height and focusing location were developed under linear long-wave conditions.
2026, 40(1)
:39-52.
doi: 10.1007/s13344-026-0003-7
Abstract:
The integrated floating energy system (IFES) comprising floating offshore wind turbines (FOWTs) and wave energy converters (WECs) presents a promising solution for reducing energy costs and enhancing motion stability. This study develops an innovative barge-type IFES integrated with multiple Wavestar prototype WECs to address this research need. A fully coupled framework is proposed for the aero-hydro-servo-elastic dynamic analysis of the wind-wave IFES concept under environmental conditions. The study analyzes time-varying platform motions and power characteristics of the IFES concepts compared to the FOWT. Results indicate that the standard deviations of platform roll and pitch decrease significantly due to the WEC integration under the most examined load cases (LCs). The system achieves a maximum reduction of 71.04% in rolling fluctuation under 16 m/s wind speed, while platform pitch decreases by 49.65%. The IFES demonstrates increased output power across all examined LCs, while tower-base loads decrease by over 20% under a wind velocity of 11 m/s. Additionally, the results indicate that the rotational dynamics of the IFES deteriorate with increasing wave period, as resonance arises when the wavelength exceeds twice the separation distance between the platform and the WEC. This phenomenon was further verified through three modified design concepts. These findings provide valuable references for offshore wind-wave hybrid system design.
The integrated floating energy system (IFES) comprising floating offshore wind turbines (FOWTs) and wave energy converters (WECs) presents a promising solution for reducing energy costs and enhancing motion stability. This study develops an innovative barge-type IFES integrated with multiple Wavestar prototype WECs to address this research need. A fully coupled framework is proposed for the aero-hydro-servo-elastic dynamic analysis of the wind-wave IFES concept under environmental conditions. The study analyzes time-varying platform motions and power characteristics of the IFES concepts compared to the FOWT. Results indicate that the standard deviations of platform roll and pitch decrease significantly due to the WEC integration under the most examined load cases (LCs). The system achieves a maximum reduction of 71.04% in rolling fluctuation under 16 m/s wind speed, while platform pitch decreases by 49.65%. The IFES demonstrates increased output power across all examined LCs, while tower-base loads decrease by over 20% under a wind velocity of 11 m/s. Additionally, the results indicate that the rotational dynamics of the IFES deteriorate with increasing wave period, as resonance arises when the wavelength exceeds twice the separation distance between the platform and the WEC. This phenomenon was further verified through three modified design concepts. These findings provide valuable references for offshore wind-wave hybrid system design.
2026, 40(1)
:53-63.
doi: 10.1007/s13344-026-0004-6
Abstract:
During typhoon landfall in coastal regions, the simultaneous occurrence of large waves and strong winds can result in substantial wave overtopping of seawalls. This paper presents a numerical wind-wave coupling model developed to examine wave overtopping characteristics of Accropode armored seawalls under combined wind and random wave conditions. The model’s validity is confirmed through experimental validation of free surface morphology and overtopping discharge measurements. Numerical analysis reveals that wind accelerates water bodies at wave crests in front of the seawall, causing forward-leaning wave crests and earlier wave overtopping events. The analysis identifies a critical wind speed of approximately 6 m/s, above which wind-induced wave overtopping increases become apparent. Under wind conditions, overtopping discharge sensitivity increases with Rc/Hm0, with notable increases observed when Rc/Hm0 exceeds approximately 1.63. This research contributes to the safety assessment of coastal structures under severe wind and wave conditions.
During typhoon landfall in coastal regions, the simultaneous occurrence of large waves and strong winds can result in substantial wave overtopping of seawalls. This paper presents a numerical wind-wave coupling model developed to examine wave overtopping characteristics of Accropode armored seawalls under combined wind and random wave conditions. The model’s validity is confirmed through experimental validation of free surface morphology and overtopping discharge measurements. Numerical analysis reveals that wind accelerates water bodies at wave crests in front of the seawall, causing forward-leaning wave crests and earlier wave overtopping events. The analysis identifies a critical wind speed of approximately 6 m/s, above which wind-induced wave overtopping increases become apparent. Under wind conditions, overtopping discharge sensitivity increases with Rc/Hm0, with notable increases observed when Rc/Hm0 exceeds approximately 1.63. This research contributes to the safety assessment of coastal structures under severe wind and wave conditions.
2026, 40(1)
:64-76.
doi: 10.1007/s13344-026-0005-5
Abstract:
Reinforced Thermoplastic Pipe (RTP) has been widely adopted in offshore oil and gas transportation because of its excellent corrosion resistance, ease of installation, and design flexibility. However, its reliability can be compromised during the laying process, where the pipe is subjected to torsion and external pressure. This study examines the evolution patterns of RTP failure modes under typical operational conditions during installation, analyzing the influence of structural parameters and torsion direction on failure modes and loads. The findings indicate that RTP exhibits strength failure under torsion, with torsion direction significantly affecting failure torque. As winding angle increases and diameter-thickness ratio decreases, the RTP failure mode transitions from buckling failure to strength failure under external pressure. The loading sequence influences the failure mode under combined action. Reinforced thermoplastic pipes (RTPs) with small diameter-thickness ratios and large winding angles demonstrate superior performance under combined external pressure and torsion in deep sea environments. An evaluation method for rapid safety state prediction is proposed based on the failure load envelope curve under combined action.
Reinforced Thermoplastic Pipe (RTP) has been widely adopted in offshore oil and gas transportation because of its excellent corrosion resistance, ease of installation, and design flexibility. However, its reliability can be compromised during the laying process, where the pipe is subjected to torsion and external pressure. This study examines the evolution patterns of RTP failure modes under typical operational conditions during installation, analyzing the influence of structural parameters and torsion direction on failure modes and loads. The findings indicate that RTP exhibits strength failure under torsion, with torsion direction significantly affecting failure torque. As winding angle increases and diameter-thickness ratio decreases, the RTP failure mode transitions from buckling failure to strength failure under external pressure. The loading sequence influences the failure mode under combined action. Reinforced thermoplastic pipes (RTPs) with small diameter-thickness ratios and large winding angles demonstrate superior performance under combined external pressure and torsion in deep sea environments. An evaluation method for rapid safety state prediction is proposed based on the failure load envelope curve under combined action.
2026, 40(1)
:77-85.
doi: 10.1007/s13344-026-0006-4
Abstract:
This study examines the impact of arched seabed configurations on the thermal buckling behavior of steel pipelines. Through mathematical calculus and a proposed movement description scheme, the potential energy is derived in explicit form. Equilibrium equations are obtained through differential calculus of the potential energy. Theoretical solutions are developed to predict critical temperature variations by solving these equilibrium equations. The current predictions demonstrate strong correlation with existing practical results. Additionally, parametric analyses evaluate the effects of geometric and material properties on the pipeline’s thermal behavior. The findings indicate that arched seabed geometry significantly influences the critical temperature variations of steel pipelines. The key contributions and conclusions are: (1) An analytical framework is established to guide the design of anchored steel pipelines on arched seabeds; (2) Explicit thermal equilibrium relationships are developed to elucidate the stabilization mechanisms of steel pipelines on arched seabeds; (3) The critical temperature change increases with greater thickness-to-radius ratios and decreasing arch radii. Consequently, thicker pipelines may provide enhanced resistance to thermal buckling in practical applications.
This study examines the impact of arched seabed configurations on the thermal buckling behavior of steel pipelines. Through mathematical calculus and a proposed movement description scheme, the potential energy is derived in explicit form. Equilibrium equations are obtained through differential calculus of the potential energy. Theoretical solutions are developed to predict critical temperature variations by solving these equilibrium equations. The current predictions demonstrate strong correlation with existing practical results. Additionally, parametric analyses evaluate the effects of geometric and material properties on the pipeline’s thermal behavior. The findings indicate that arched seabed geometry significantly influences the critical temperature variations of steel pipelines. The key contributions and conclusions are: (1) An analytical framework is established to guide the design of anchored steel pipelines on arched seabeds; (2) Explicit thermal equilibrium relationships are developed to elucidate the stabilization mechanisms of steel pipelines on arched seabeds; (3) The critical temperature change increases with greater thickness-to-radius ratios and decreasing arch radii. Consequently, thicker pipelines may provide enhanced resistance to thermal buckling in practical applications.
2026, 40(1)
:86-105.
doi: 10.1007/s13344-026-0007-3
Abstract:
Mining risers are vulnerable to complex nonlinear flow-induced vibration (FIV) failure due to the combined effects of internal gas-liquid-solid three-phase flow and external ocean loads. This study establishes a gas-liquid-solid three-phase FIV model of the deep-sea hydrate mining riser using the finite element method and Hamilton’s principle. A nonlinear vibration simulation experimental device for the mining riser has been developed. The model’s accuracy is validated by comparing experimental test results with theoretical model calculations. The study analyzes the influence of external environmental parameters and multiphase flow parameters on riser fatigue life. Results indicate that parameter increases intensify riser fatigue damage. Alternating stress has a more pronounced effect on riser fatigue life than the dominant frequency. During riser resonance, both triaxial stress and stress main frequency increase, leading to a sharp decrease in overall riser fatigue life. The research demonstrates that adjusting readily controllable operating parameters can effectively enhance riser vibration amplitude frequency, thereby extending fatigue life and ensuring safe, stable deep-sea hydrate mining operations.
Mining risers are vulnerable to complex nonlinear flow-induced vibration (FIV) failure due to the combined effects of internal gas-liquid-solid three-phase flow and external ocean loads. This study establishes a gas-liquid-solid three-phase FIV model of the deep-sea hydrate mining riser using the finite element method and Hamilton’s principle. A nonlinear vibration simulation experimental device for the mining riser has been developed. The model’s accuracy is validated by comparing experimental test results with theoretical model calculations. The study analyzes the influence of external environmental parameters and multiphase flow parameters on riser fatigue life. Results indicate that parameter increases intensify riser fatigue damage. Alternating stress has a more pronounced effect on riser fatigue life than the dominant frequency. During riser resonance, both triaxial stress and stress main frequency increase, leading to a sharp decrease in overall riser fatigue life. The research demonstrates that adjusting readily controllable operating parameters can effectively enhance riser vibration amplitude frequency, thereby extending fatigue life and ensuring safe, stable deep-sea hydrate mining operations.
2026, 40(1)
:106-119.
doi: 10.1007/s13344-026-0008-2
Abstract:
Maritime collision accidents occur frequently and result in severe consequences, constituting approximately 60% of maritime incidents. Human error accounts for 75%−96% of these collisions, emphasizing the necessity for intelligent decision-making systems. This study proposes a fuzzy inference system for multi-ship collision avoidance decision-making based on dynamic collision risk assessment incorporating multiple ship interactions. The proposed method enhances collision avoidance through two primary innovations: a finite state mechanism for dynamic multi-ship interaction analysis and game-theoretic collision-avoidance strategies that integrate real-time behavioural responses with Convention on the International Regulations for Preventing Collisions at Sea (COLREGs) compliance. The IF-THEN rule incorporates action strategies, ship behaviour, and navigation rules, with collision avoidance decisions derived through the fuzzy inference system. This framework uniquely addresses collision risk evaluation by integrating dynamic risk assessment and ship interaction strategies, enabling proactive adjustments that maintain safety margins while adhering to maritime regulations. Simulation experiments assess multi-ship collision-avoidance maneuvers under various interaction scenarios, demonstrating the model’s ability to execute timely adjustments and effectively mitigate collision risks among multiple target vessels, thereby ensuring minimal exposure during encounters.
Maritime collision accidents occur frequently and result in severe consequences, constituting approximately 60% of maritime incidents. Human error accounts for 75%−96% of these collisions, emphasizing the necessity for intelligent decision-making systems. This study proposes a fuzzy inference system for multi-ship collision avoidance decision-making based on dynamic collision risk assessment incorporating multiple ship interactions. The proposed method enhances collision avoidance through two primary innovations: a finite state mechanism for dynamic multi-ship interaction analysis and game-theoretic collision-avoidance strategies that integrate real-time behavioural responses with Convention on the International Regulations for Preventing Collisions at Sea (COLREGs) compliance. The IF-THEN rule incorporates action strategies, ship behaviour, and navigation rules, with collision avoidance decisions derived through the fuzzy inference system. This framework uniquely addresses collision risk evaluation by integrating dynamic risk assessment and ship interaction strategies, enabling proactive adjustments that maintain safety margins while adhering to maritime regulations. Simulation experiments assess multi-ship collision-avoidance maneuvers under various interaction scenarios, demonstrating the model’s ability to execute timely adjustments and effectively mitigate collision risks among multiple target vessels, thereby ensuring minimal exposure during encounters.
2026, 40(1)
:120-131.
doi: 10.1007/s13344-026-0009-1
Abstract:
Turning performance represents a critical indicator of underwater vehicle maneuverability and correlates strongly with motion parameters such as rudder angle and propeller speed. This investigation examines the influence of rudder angle and propeller speed on underwater vehicle turning performance. A fully coupled CFD-based hull-propeller-rudder model enables high-accuracy computation of turning performance. The propeller modeling utilizes the body force method, while the overlapping mesh technique addresses the relative motion between rudder and hull. To optimize computational efficiency, an optimal Latin hypercube sampling method generates combinations of rudder angle and propeller speed, and a Kriging surrogate model substitutes for resource-intensive CFD simulations. Through application of the improved Sobol’s method, global sensitivity analysis quantitatively evaluates the contributions of rudder angle and propeller speed to turning performance. The analysis reveals that rudder angle substantially impacts turning performance, whereas propeller speed demonstrates comparatively limited influence.
Turning performance represents a critical indicator of underwater vehicle maneuverability and correlates strongly with motion parameters such as rudder angle and propeller speed. This investigation examines the influence of rudder angle and propeller speed on underwater vehicle turning performance. A fully coupled CFD-based hull-propeller-rudder model enables high-accuracy computation of turning performance. The propeller modeling utilizes the body force method, while the overlapping mesh technique addresses the relative motion between rudder and hull. To optimize computational efficiency, an optimal Latin hypercube sampling method generates combinations of rudder angle and propeller speed, and a Kriging surrogate model substitutes for resource-intensive CFD simulations. Through application of the improved Sobol’s method, global sensitivity analysis quantitatively evaluates the contributions of rudder angle and propeller speed to turning performance. The analysis reveals that rudder angle substantially impacts turning performance, whereas propeller speed demonstrates comparatively limited influence.
2026, 40(1)
:132-143.
doi: 10.1007/s13344-026-0010-8
Abstract:
Accurate and efficient prediction of ocean waves and storm surges induced by tropical cyclones is essential for coastal hazard mitigation and maritime safety. While traditional numerical models are reliable, they require substantial computational resources. Deep learning (DL) offers an alternative approach for modeling these phenomena. Although existing DL models typically address ocean waves or storm surges separately, both phenomena represent responses to atmospheric forcing, suggesting that they can be modeled using identical underlying principles within a data-driven framework. This study, guided by the physics of ocean wave and storm surge generation and evolution, presents a unified DL model that simultaneously predicts both phenomena using current and historical wind and sea level pressure field data. The model effectively captures the complex nonlinear relationships between meteorological inputs and hydrodynamic outputs with high accuracy. Results demonstrate that the proposed model accurately predicts both significant wave height (SWH) and storm surge height, showing strong correlation with numerical models and validating our hypothesis that these phenomena can be modeled collectively using identical input parameters. The model demonstrates superior computational efficiency compared with traditional numerical models while maintaining high accuracy, making it particularly suitable for real-time operational forecasting and climate research of ocean waves and storm surges.
Accurate and efficient prediction of ocean waves and storm surges induced by tropical cyclones is essential for coastal hazard mitigation and maritime safety. While traditional numerical models are reliable, they require substantial computational resources. Deep learning (DL) offers an alternative approach for modeling these phenomena. Although existing DL models typically address ocean waves or storm surges separately, both phenomena represent responses to atmospheric forcing, suggesting that they can be modeled using identical underlying principles within a data-driven framework. This study, guided by the physics of ocean wave and storm surge generation and evolution, presents a unified DL model that simultaneously predicts both phenomena using current and historical wind and sea level pressure field data. The model effectively captures the complex nonlinear relationships between meteorological inputs and hydrodynamic outputs with high accuracy. Results demonstrate that the proposed model accurately predicts both significant wave height (SWH) and storm surge height, showing strong correlation with numerical models and validating our hypothesis that these phenomena can be modeled collectively using identical input parameters. The model demonstrates superior computational efficiency compared with traditional numerical models while maintaining high accuracy, making it particularly suitable for real-time operational forecasting and climate research of ocean waves and storm surges.
2026, 40(1)
:144-157.
doi: 10.1007/s13344-026-0011-7
Abstract:
Due to complex environmental disturbances, high-precision tidal prediction remains a significant challenge in ocean engineering applications. To address tidal variations characterized by nonlinearity, uncertainty, and time-varying dynamics, a hybrid prediction scheme incorporating adaptive module adjustment (AMA) is proposed. The harmonic analysis method is first applied to model tidal effects induced by the movements of celestial bodies. Subsequently, residual components are decomposed using empirical mode decomposition (EMD), with long short-term memory (LSTM) networks and polynomial fitting (PF) employed to construct the tidal prediction model. The decomposition order for LSTM input time series and the selection of polynomial modules are determined adaptively. Finally, the predictions from harmonic analysis and the ensemble model components are combined to generate the final tidal forecast. Experimental simulations are conducted using observed tidal data from gauges at Canaveral Port and Old Port Tampa. Simulation results demonstrate that the proposed adaptive tidal prediction model outperforms conventional methods in terms of prediction accuracy.
Due to complex environmental disturbances, high-precision tidal prediction remains a significant challenge in ocean engineering applications. To address tidal variations characterized by nonlinearity, uncertainty, and time-varying dynamics, a hybrid prediction scheme incorporating adaptive module adjustment (AMA) is proposed. The harmonic analysis method is first applied to model tidal effects induced by the movements of celestial bodies. Subsequently, residual components are decomposed using empirical mode decomposition (EMD), with long short-term memory (LSTM) networks and polynomial fitting (PF) employed to construct the tidal prediction model. The decomposition order for LSTM input time series and the selection of polynomial modules are determined adaptively. Finally, the predictions from harmonic analysis and the ensemble model components are combined to generate the final tidal forecast. Experimental simulations are conducted using observed tidal data from gauges at Canaveral Port and Old Port Tampa. Simulation results demonstrate that the proposed adaptive tidal prediction model outperforms conventional methods in terms of prediction accuracy.
2026, 40(1)
:158-168.
doi: 10.1007/s13344-026-0012-6
Abstract:
The negative pressure near-wall particle collection method employs suction flow to circulate the medium along the inner wall of the collection port, creating flow separation that affects flow characteristics and particle forces. This investigation utilizes a CFD simulation method, validated through Zhao’s experiments, and implements a “circular pipe suction model” to examine how collection port parameters—specifically wall thickness and shape—influence the flow field and particle collection efficiency across different Reynolds numbers. The findings demonstrate that wall thickness and port shape substantially affect flow separation, as evidenced by recirculation zones that compress the flow and modify the particle force coefficient. Typically, greater wall thickness results in decreased particle force coefficients, with variations up to 15%. Moreover, collection ports with inward-pointing sharp angles demonstrate the highest particle force coefficients, while those with outward-pointing angles show the lowest, exhibiting variations up to 23%. These results indicate that optimizing collection port design through wall thickness and shape modifications can improve particle collection efficiency, enhancing practical applications.
The negative pressure near-wall particle collection method employs suction flow to circulate the medium along the inner wall of the collection port, creating flow separation that affects flow characteristics and particle forces. This investigation utilizes a CFD simulation method, validated through Zhao’s experiments, and implements a “circular pipe suction model” to examine how collection port parameters—specifically wall thickness and shape—influence the flow field and particle collection efficiency across different Reynolds numbers. The findings demonstrate that wall thickness and port shape substantially affect flow separation, as evidenced by recirculation zones that compress the flow and modify the particle force coefficient. Typically, greater wall thickness results in decreased particle force coefficients, with variations up to 15%. Moreover, collection ports with inward-pointing sharp angles demonstrate the highest particle force coefficients, while those with outward-pointing angles show the lowest, exhibiting variations up to 23%. These results indicate that optimizing collection port design through wall thickness and shape modifications can improve particle collection efficiency, enhancing practical applications.
2026, 40(1)
:169-182.
doi: 10.1007/s13344-026-0013-5
Abstract:
This study presents a novel offshore expandable HMFS system that integrates the functions of a floating breakwater and wave energy converters (WECs), offering an alternative approach to marine space development. A scaled experimental model was developed, consisting of hybrid functional modules, inter-module connectors, a mooring system, and integrated WEC units. The design incorporates WECs driven by parallel-axis gears and hinge connectors with linear torsional stiffness. The research experimentally examines the effects of connector stiffness, longitudinal spatial expansion, and mooring line fracture on key dynamic responses. The findings demonstrate that enhanced connector stiffness reduces module motion responses while increasing connector loads, providing experimental guidance for connector selection. The hinge-connected system demonstrates stable dynamic performance, while the rigid-connected system exhibits significant increases in pitch bending moment during longitudinal spatial expansion. Analysis of single mooring line fracture suggests avoiding systems with minimal mooring lines to prevent excessive planar displacement. These findings provide valuable experimental insights for the engineering implementation of the HMFS system.
This study presents a novel offshore expandable HMFS system that integrates the functions of a floating breakwater and wave energy converters (WECs), offering an alternative approach to marine space development. A scaled experimental model was developed, consisting of hybrid functional modules, inter-module connectors, a mooring system, and integrated WEC units. The design incorporates WECs driven by parallel-axis gears and hinge connectors with linear torsional stiffness. The research experimentally examines the effects of connector stiffness, longitudinal spatial expansion, and mooring line fracture on key dynamic responses. The findings demonstrate that enhanced connector stiffness reduces module motion responses while increasing connector loads, providing experimental guidance for connector selection. The hinge-connected system demonstrates stable dynamic performance, while the rigid-connected system exhibits significant increases in pitch bending moment during longitudinal spatial expansion. Analysis of single mooring line fracture suggests avoiding systems with minimal mooring lines to prevent excessive planar displacement. These findings provide valuable experimental insights for the engineering implementation of the HMFS system.
2026, 40(1)
:183-193.
doi: 10.1007/s13344-026-0014-4
Abstract:
LNG membrane tanks feature a composite structure, with the 304 L stainless steel membrane serving as a critical component. Ensuring membrane reliability and safety under extreme low-temperature conditions requires systematic investigation of their mechanical properties. This study presents numerical simulations and experimental verification of LNG membrane mechanical properties. Through quasistatic tensile tests, finite element simulations, and actual model tests, the research established stress-strain curves of 304 L stainless steel at various temperatures and examined the mechanical behavior and deformation characteristics of LNG membranes at low temperatures. The findings demonstrate that 304 L stainless steel exhibits significantly increased tensile strength at low temperatures, while showing decreased elongation. Under low-temperature conditions, small corrugations display reduced extensibility but enhanced tensile strength, whereas large corrugations demonstrate opposite characteristics. Furthermore, this study elucidates the permanent deformation patterns of LNG membranes under low-temperature and high-load conditions. The maximum displacement of membranes increases with load in both large and small corrugation areas, though their recovery capability improves at low temperatures, with varying tensile and elongation properties in different directions. Based on these results, the study proposes a calibration standard for LNG membranes, providing theoretical foundations for practical applications.
LNG membrane tanks feature a composite structure, with the 304 L stainless steel membrane serving as a critical component. Ensuring membrane reliability and safety under extreme low-temperature conditions requires systematic investigation of their mechanical properties. This study presents numerical simulations and experimental verification of LNG membrane mechanical properties. Through quasistatic tensile tests, finite element simulations, and actual model tests, the research established stress-strain curves of 304 L stainless steel at various temperatures and examined the mechanical behavior and deformation characteristics of LNG membranes at low temperatures. The findings demonstrate that 304 L stainless steel exhibits significantly increased tensile strength at low temperatures, while showing decreased elongation. Under low-temperature conditions, small corrugations display reduced extensibility but enhanced tensile strength, whereas large corrugations demonstrate opposite characteristics. Furthermore, this study elucidates the permanent deformation patterns of LNG membranes under low-temperature and high-load conditions. The maximum displacement of membranes increases with load in both large and small corrugation areas, though their recovery capability improves at low temperatures, with varying tensile and elongation properties in different directions. Based on these results, the study proposes a calibration standard for LNG membranes, providing theoretical foundations for practical applications.
2026, 40(1)
:194-206.
doi: 10.1007/s13344-026-0015-3
Abstract:
This study developed a two-dimensional storm surge model for hydrodynamic simulations in port engineering, utilizing an improved Local Time-Stepping (LTS) scheme. The model implements unstructured triangular grids with localized refinement within the engineering area, enhancing computational efficiency through the improved LTS algorithm. Implementation in a Qingdao port demonstrated that, compared with the conventional Global Time-Stepping (GTS) scheme, the LTS approach enhanced computational efficiency by 5.08 times and 3.30 times before and after construction, respectively, reducing computation time by 30−40 hours. Validation results confirm the model’s high accuracy under both astronomical tide and storm surge conditions. Simulations of storm surges during Severe Typhoon Muifa (1109) and Super Typhoon Lekima (2019) further validated the model’s effectiveness. The results indicated that the overall simulation trend of storm surge aligned closely with the observed patterns of water level fluctuations, yielding highly satisfactory results. The Root Mean Square Error (RMSE) for Typhoon Lekima was 0.0083 m, while for Typhoon Muifa it was 0.0059 m, further demonstrating the model’s accuracy and applicability. The study analyzed the storm surge flow field post-construction using Typhoon Lekima as a case study. This research demonstrates the LTS model’s significant potential and promising applications in storm surge simulations and marine port construction.
This study developed a two-dimensional storm surge model for hydrodynamic simulations in port engineering, utilizing an improved Local Time-Stepping (LTS) scheme. The model implements unstructured triangular grids with localized refinement within the engineering area, enhancing computational efficiency through the improved LTS algorithm. Implementation in a Qingdao port demonstrated that, compared with the conventional Global Time-Stepping (GTS) scheme, the LTS approach enhanced computational efficiency by 5.08 times and 3.30 times before and after construction, respectively, reducing computation time by 30−40 hours. Validation results confirm the model’s high accuracy under both astronomical tide and storm surge conditions. Simulations of storm surges during Severe Typhoon Muifa (1109) and Super Typhoon Lekima (2019) further validated the model’s effectiveness. The results indicated that the overall simulation trend of storm surge aligned closely with the observed patterns of water level fluctuations, yielding highly satisfactory results. The Root Mean Square Error (RMSE) for Typhoon Lekima was 0.0083 m, while for Typhoon Muifa it was 0.0059 m, further demonstrating the model’s accuracy and applicability. The study analyzed the storm surge flow field post-construction using Typhoon Lekima as a case study. This research demonstrates the LTS model’s significant potential and promising applications in storm surge simulations and marine port construction.
2026, 40(1)
:207-218.
doi: 10.1007/s13344-026-0016-2
Abstract:
This study proposes a multi-net trash barrier system to ensure water intake safety in nuclear power plants, comprising various planar nets and net bags supported by piles and anchor blocks. A comprehensive physical model experiment was conducted in a three-dimensional wave basin to investigate the mooring forces on this barrier. The research analyzes the effect of blockage levels on the dynamic responses of pile-supported and floating nets within blockage ratios of 10%−70% under current-only, wave-only, and wave-current conditions. For optimal net span design, the study examines curvatures ranging from 0.2% to 18.6%, representing the extension proportion of arc length compared to straight-line distance in a span. Results indicate that combined water intake and wave action effects generate substantial forces on the net barrier, requiring careful consideration during design. Higher blockage ratios and lower curvatures correspond to increased net barrier tensions. For practical engineering applications, the recommended curvature for floating net barriers ranges from 7% to 10% for optimal net arc length design.
This study proposes a multi-net trash barrier system to ensure water intake safety in nuclear power plants, comprising various planar nets and net bags supported by piles and anchor blocks. A comprehensive physical model experiment was conducted in a three-dimensional wave basin to investigate the mooring forces on this barrier. The research analyzes the effect of blockage levels on the dynamic responses of pile-supported and floating nets within blockage ratios of 10%−70% under current-only, wave-only, and wave-current conditions. For optimal net span design, the study examines curvatures ranging from 0.2% to 18.6%, representing the extension proportion of arc length compared to straight-line distance in a span. Results indicate that combined water intake and wave action effects generate substantial forces on the net barrier, requiring careful consideration during design. Higher blockage ratios and lower curvatures correspond to increased net barrier tensions. For practical engineering applications, the recommended curvature for floating net barriers ranges from 7% to 10% for optimal net arc length design.
2026, 40(1)
:219-229.
doi: 10.1007/s13344-026-0017-1
Abstract:
The multi-stage seawall is a novel coastal structure designed to protect shoreline landscapes and infrastructure. However, studies on wave interactions with such structures remain limited. In this study, a numerical model based on OpenFOAM® was developed to simulate wave propagation over a multi-stage seawall. The two-phase incompressible Navier-Stokes equations were solved, incorporating the k−ε turbulence closure model and a modified Volume of Fluid (VOF) method for accurate free-surface tracking. The model was validated against both newly acquired laboratory data and published results, showing good agreement in predicted free-surface elevations along the seawall. A series of numerical experiments were conducted to analyze wave evolution and overtopping discharge across the multi-stage platforms, with particular focus on the interplay between vertical step heights and horizontal platform widths. Based on the results, a modified formula for estimating wave overtopping at multi-stage seawalls was proposed. These findings contribute to a better understanding of hydrodynamic behavior and support improved engineering design of multi-stage seawalls.
The multi-stage seawall is a novel coastal structure designed to protect shoreline landscapes and infrastructure. However, studies on wave interactions with such structures remain limited. In this study, a numerical model based on OpenFOAM® was developed to simulate wave propagation over a multi-stage seawall. The two-phase incompressible Navier-Stokes equations were solved, incorporating the k−ε turbulence closure model and a modified Volume of Fluid (VOF) method for accurate free-surface tracking. The model was validated against both newly acquired laboratory data and published results, showing good agreement in predicted free-surface elevations along the seawall. A series of numerical experiments were conducted to analyze wave evolution and overtopping discharge across the multi-stage platforms, with particular focus on the interplay between vertical step heights and horizontal platform widths. Based on the results, a modified formula for estimating wave overtopping at multi-stage seawalls was proposed. These findings contribute to a better understanding of hydrodynamic behavior and support improved engineering design of multi-stage seawalls.
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- February 2026
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Nanjing Hydraulic Research Institute
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