Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121949
Kevin Duffy , Cormac Reale , Ken Gavin
{"title":"Analytical approach to predicting pile self-weight penetration, considering penetration rate effects","authors":"Kevin Duffy , Cormac Reale , Ken Gavin","doi":"10.1016/j.oceaneng.2025.121949","DOIUrl":"10.1016/j.oceaneng.2025.121949","url":null,"abstract":"<div><div>As offshore pile foundations increase in diameter and weight, the risk of uncontrolled and unsafe penetration events (pile run) also increases. Traditional approaches to evaluating this risk rely on static resistance to driving (SRD) formulations, equating the SRD to the effective weight of the pile. However, high penetration speeds during uncontrolled pile penetration can lead to a soil response much different to static conditions, particularly with regards to pore pressure dissipation around the pile. With this in mind, the paper proposes an analytical model for determining when uncontrolled penetration may occur and its extent. The model integrates novel SRD formulations with a penetration rate effect model, both of which are derived from cone penetration test (CPT) measurements. The model's predictions were then benchmarked against industry-standard methods using a database of self-weight penetration events in clays and sands of varying densities and strengths. The predicted self-weight penetrations compared well with field observations across the full range of soil conditions and gave a better performance compared to standard prediction methods. Furthermore, the results emphasise the critical role of soil volumetric behaviour during shearing and future research should clarify the influence of rapid penetration on the pile's shaft and base resistance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121949"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338461","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121923
Lei Zhang , Tuowei Chen , Zaili Yang , Lei Du , Langxiong Gan , Xiaobin Li
{"title":"Collision avoidance decision-making for stand-on ships through inference of give-way ship intention in complex encounters","authors":"Lei Zhang , Tuowei Chen , Zaili Yang , Lei Du , Langxiong Gan , Xiaobin Li","doi":"10.1016/j.oceaneng.2025.121923","DOIUrl":"10.1016/j.oceaneng.2025.121923","url":null,"abstract":"<div><div>Rationally determining the optimal timing and devising effective collision avoidance strategies are crucial for stand-on ships in complex encounter scenarios. Given the absence of explicit COLREGs guidelines on when and how a stand-on ship should initiate an evasive action, a collision avoidance method from the stand-on ship's perspective through inferring the give-way ship's intention is necessary to be developed. By continuously monitoring and analyzing the give-way ship's behavior, this paper employs Dempster-Shafer theory to assess its cooperative intention, enabling rational determination of the optimal timing for action. The improved nonlinear velocity obstacle method, incorporating the stand-on ship's maneuvering capabilities, is then used to generate a set of feasible anti-collision decision strategies. A NSGA-II algorithm helps optimally select a strategy that can balance safety and navigational efficiency. Simulation results demonstrate that the newly proposed approach enhances stand-on ships' situational awareness across varying levels of give-way ship cooperation, effectively mitigating collision risks while significantly reducing route recovery time and course deviation.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"337 ","pages":"Article 121923"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338415","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121958
Zhehao Shi, Chaoguang Jin, Xin Zhang, Guan Guan, Jie Cui
{"title":"Calculation method for underwater towing cable attitude based on improved theoretical analysis method","authors":"Zhehao Shi, Chaoguang Jin, Xin Zhang, Guan Guan, Jie Cui","doi":"10.1016/j.oceaneng.2025.121958","DOIUrl":"10.1016/j.oceaneng.2025.121958","url":null,"abstract":"<div><div>Underwater towing system has been widely used in the fields of marine environment exploration, marine geological survey, seabed mapping and so on. To accurately solve the cable position of underwater towing system, This study proposes a CFD- Analytical hybrid model with dynamic coefficient optimization (DIO-Model) to address these limitations. In the process of solving, the normal drag coefficient <span><math><mrow><msub><mi>C</mi><mi>n</mi></msub></mrow></math></span> and tangential drag coefficient <span><math><mrow><msub><mi>C</mi><mi>t</mi></msub></mrow></math></span> of the towing cable under the corresponding working conditions are precisely solved and adjusted by CFD to improve the numerical solving accuracy, and the established method of solving for the position of the cable has the advantage of high computational accuracy, with the maximal error of only 1.026 %. It realizes the accurate solving of cable position attitude of underwater towing system. When calculating underwater towing problems, this method can simultaneously take into account the calculation speed and accuracy, which has certain advantages compared with other methods. Compared with AQWA software, the calculation accuracy is improved by 2 %, and compared with STAR-CCM + software, the calculation time is reduced by 80 %. The results can provide theoretical support for the design optimization and operation process control of underwater towing system.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121958"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338463","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121911
Pengfei Si, Ningfei Wang, Shipeng Li, Ge Jin, Muyang Feng
{"title":"Flow characteristics of underwater supersonic gas jets formed by the scarfed nozzle","authors":"Pengfei Si, Ningfei Wang, Shipeng Li, Ge Jin, Muyang Feng","doi":"10.1016/j.oceaneng.2025.121911","DOIUrl":"10.1016/j.oceaneng.2025.121911","url":null,"abstract":"<div><div>Underwater supersonic gas jets formed by the scarfed nozzle are commonly found in underwater propulsion systems. The investigation is conducted using both experimental and numerical methods. High-speed imaging and image processing techniques are employed in the experiments, and the Volume of Fluid (VOF) model is used in the numerical simulations. The effects of different nozzle expansion states on the jet flow characteristics are studied. The study focuses on the flow dynamics and instabilities of the underwater gas jets, considering two stages of jet formation: the initial gas bubble and the stable conical structure. It is found that asymmetric characteristics appear in the jet morphology, pressure and gas-liquid interface oscillations, and thrust of the scarfed nozzle. Significant pressure oscillations occur in the initial stage. However, the gas-liquid interface continues to exhibit oscillations with asymmetric behavior, which weakens as the inlet pressure increases. The deflection characteristics of the thrust direction are heavily influenced by the non-axisymmetric geometry and lateral forces exerted on the asymmetric wall of the nozzle. These findings contribute to a more profound comprehension of the intricate mechanism of underwater gas jets of the scarfed nozzle, thereby facilitating the development of more efficient and stable underwater propulsion systems.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121911"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338460","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121948
Zunfeng Du , Yuan Yang , Haiming Zhu , Jingbo Yang , Muxuan Han , Yuguang Fu
{"title":"Design optimization of inclined pile permeable breakwater based on a CFD-SVR-WO framework","authors":"Zunfeng Du , Yuan Yang , Haiming Zhu , Jingbo Yang , Muxuan Han , Yuguang Fu","doi":"10.1016/j.oceaneng.2025.121948","DOIUrl":"10.1016/j.oceaneng.2025.121948","url":null,"abstract":"<div><div>The design and optimization of breakwaters is a crucial yet challenging problem in port and coastal engineering, as evaluating their wave dissipation characteristics is usually associated with high experimental or computational expenses. To achieve rapid and comprehensive optimization of an inclined pile permeable (IPP) breakwater, this study proposed a surrogate model -based optimization framework integrating computational fluid dynamics (CFD), support vector regression (SVR), and walrus optimizer (WO). Firstly, a three-dimensional numerical wave tank was established to evaluate the wave dissipation capacity of the breakwater. The accuracy of the model was validated through model tests. Then, a surrogate model was trained using SVR based on the data obtained from 103 high-fidelity CFD simulations. The hydrodynamic properties of the IPP breakwater under different wave periods were analyzed, showing that the IPP breakwater has better wave dissipation capability for short-period waves. Finally, an optimized design was given by applying WO under constraints of minimum permeability at 0.22 and maximum volume per unit length at 36 m<sup>2</sup>. The proposed CFD-SVR-WO framework demonstrated a significant reduction in computational cost, validating its feasibility in handling complex optimizations for engineering structures.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121948"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338464","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121836
Anqi Niu , Wei Wang , Weihan Qiu , Shenghai Wang , Yuqing Sun
{"title":"Horizontal control strategy of 3UPU/UP offshore parallel platform based on forward and inverse kinematic models","authors":"Anqi Niu , Wei Wang , Weihan Qiu , Shenghai Wang , Yuqing Sun","doi":"10.1016/j.oceaneng.2025.121836","DOIUrl":"10.1016/j.oceaneng.2025.121836","url":null,"abstract":"<div><div>This paper presents a nonlinear output regulation controller (NORC) for an offshore parallel stabilized platform. Previous controllers had relied on kinematic analysis and were unable to simultaneously control both the angles and the height of the upper plate. The controller proposed in this paper addresses these limitations while accounting for unmeasurable disturbances arising from mechanical structural errors. Additionally, it is computationally less burdensome than controllers relying on mechanism dynamic models. First, a forward kinematic model for the 3UPU/UP (U denotes the Hooke's joint, and P denotes the prismatic pair) parallel mechanism, which yields a unique analytical solution, has been derived for the first time. Subsequently, a NORC was developed using forward and inverse kinematic models. Through further improvements, the modified NORC can utilize imprecise kinematic models to achieve precise control. Moreover, a dual cost function was proposed to dynamically calculate the controller gain, thus minimizing the system's overshoot. Finally, the control effects of PID, sliding mode control (SMC), NORC, and the modified NORC were compared through co-simulations and real prototype experiments. Results demonstrated that the modified NORC is more efficient, and the dual cost function successfully reduces the system's overshoot.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121836"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338462","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121934
R.X. Yong , L.K. Quen , L.K. Tan , X.C. Yak , H.S. Kang , K.Y. Wong
{"title":"Experimental investigation on the suppression of vortex-induced vibration of a rigid cylinder using axial slats","authors":"R.X. Yong , L.K. Quen , L.K. Tan , X.C. Yak , H.S. Kang , K.Y. Wong","doi":"10.1016/j.oceaneng.2025.121934","DOIUrl":"10.1016/j.oceaneng.2025.121934","url":null,"abstract":"<div><div>The study on suppression capabilities of axial slats on vortex-induced vibration (VIV) was carried out in a circulating water flume. This study aimed to find out the best combination of coverage ratio (CR) and gap ratio (GR) for the axial slats. The cylinders were set up to move in both cross-flow (CF) and in-line (IL) directions, with Reynolds number ranging from 7336 to 39346. Amplitude ratios, frequency ratios, lift and drag coefficients, trajectories and power spectral densities (PSD) were studied. A combination of CR = 0.3 and GR = 0.20 was found to be the best for axial slats to effectively suppress VIV, reducing up to 71.4 % of the CF amplitude of a bare cylinder. The best lift reduction of about 86.2 % was also found for axial slats of the same configuration. All axial slats configurations showed mean drag reduction compared to the bare cylinder, with the best reduction of 47.9 % for axial slats with CR = 0.3 and GR = 0.20. Additionally, GR was also found to have a greater influence than CR on the VIV suppression capability of axial slats.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121934"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338465","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121962
Zhourui Li, Jiangming Ding, Jianhua Zhang
{"title":"Research on the design and optimization of the single-jet volute for the baseplate omnidirectional waterjet","authors":"Zhourui Li, Jiangming Ding, Jianhua Zhang","doi":"10.1016/j.oceaneng.2025.121962","DOIUrl":"10.1016/j.oceaneng.2025.121962","url":null,"abstract":"<div><div>The volute is essential for thrust generation and omnidirectional steering in the baseplate omnidirectional waterjet. The current volute design faces two challenges: insufficient documentation on design methodologies and structural complexity in widely-used three-jet volutes, increasing production challenges and costs. This paper presents an optimization of the single-jet volute design in baseplate omnidirectional waterjets to enhance performance. (1) A typical three-jet volute baseplate omnidirectional waterjet is utilized as the prototype. The improved single-jet volute is geometrically modelled and parameterized. (2)The single-jet volute design parameter space is constructed using Latin Hypercube Sampling (LHS). (3) The RANS viscous flow method is employed to obtain the propulsion performance indicators of the sample space. (4) The multilayer perceptron (MLP) neural network has been used to expand the sample space. (5)The Non-Dominated Sorting Genetic Algorithm III (NSGA-III) is used to determine the optimal volute design parameter combination. The optimized single-jet volute, simpler than the three-jet volute, exhibits superior propulsion performance. The single-jet volute reduces shaft power by 3.7 % and increases the thrust-to-power ratio <em>F</em><sub>x</sub>/<em>P</em> by approximately 5.1 % compared to the three-jet volute, while its simplified structure lowers manufacturing costs. The findings of this paper can serve as a reference for design optimization of this specialized propulsion system.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121962"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365845","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121964
Yixuan Wang , Xingru Qu , Zhibin Li
{"title":"Optimizing pre-occurrence maritime search and rescue system: A dynamic location-allocation model with considering spatiotemporal accessibility","authors":"Yixuan Wang , Xingru Qu , Zhibin Li","doi":"10.1016/j.oceaneng.2025.121964","DOIUrl":"10.1016/j.oceaneng.2025.121964","url":null,"abstract":"<div><div>This study presents a novel approach to optimizing a pre-occurrence search and rescue (SAR) system to enhance both efficiency and cost-effectiveness in maritime emergency. First, we formulate a dynamic location-allocation problem (LAP) for rescue resources (including rescue stations at sea, rescue vessels, and emergency supplies) under multi-period scenarios, simultaneously accounting for seasonal variations in incident demand, rescue capacity, and oceanic conditions. To quantify the impact of these variations on LAP decision-making, we integrate a spatiotemporal SAR accessibility measure, enabling seasonal reallocation of SAR resources across different scenarios. The model aims to achieve two key objectives: maximizing expected accessibility to incidents and minimizing total system costs. To solve this complex problem, we employ a hybrid algorithm that combines <em>k</em>-means clustering with the multi-objective plant growth simulation algorithm (MO-PGSA). A real-life case study in the Bohai Sea, China, validates the effectiveness of the proposed approach, with numerical results demonstrating significant improvements in SAR system performance. The findings offer valuable decision support for strategic SAR planning, enhance resource utilization, and contribute to improved maritime safety management.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"337 ","pages":"Article 121964"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338488","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}
Ocean EngineeringPub Date : 2025-06-23DOI: 10.1016/j.oceaneng.2025.121883
Hongjian Wu , Hongda Shi , Feifei Cao , Mingqi Yu , Meng Han , Xi Yi , Jiajun Chen
{"title":"Numerical study of Bragg resonance reflection for wave energy converter arrays in a two-dimensional viscous wave tank","authors":"Hongjian Wu , Hongda Shi , Feifei Cao , Mingqi Yu , Meng Han , Xi Yi , Jiajun Chen","doi":"10.1016/j.oceaneng.2025.121883","DOIUrl":"10.1016/j.oceaneng.2025.121883","url":null,"abstract":"<div><div>Bragg resonance occurs when the spacing between periodic coastal structures is approximately half the incident wavelength, which significantly reduces the energy extraction efficiency of wave energy converter (WEC) arrays. This effect was studied by establishing a quasi-two-dimensional viscous numerical wave tank (NWT) using a computational fluid dynamics (CFD) approach to simulate nonlinear wave interactions with a linear array of three floating WECs. Following convergence analysis and model validation, the wave propagation, dynamic responses and energy capture characteristics of the array were evaluated under three conditions: fixed, freely heaving, and energy-extracting. Bragg resonance occurred at 2<em>S</em>/<em>L</em> = 1.2 in the fixed case and at 2<em>S</em>/<em>L</em> = 0.9 in the moving case, corresponding to phase-up and phase-down shifts, respectively. Under energy-extracting conditions, a substantial power reduction of up to 53.1 % was observed during resonance, with the first and third WECs oscillating in phase and the middle WEC in counter-phase. The adverse effect of Bragg resonance on power output became more pronounced with increasing power take-off (PTO) levels. These findings offer practical insights for the design of floating breakwaters and the optimization of WEC array configurations to improve energy performance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121883"},"PeriodicalIF":4.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338358","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}