Applied Ocean Research最新文献

{"title":"Two-dimensional numerical modelling of a novel heaving wave energy converter-perforated breakwater integrated system","authors":"Dongxu Wang ,&nbsp;Sheng Dong","doi":"10.1016/j.apor.2024.104274","DOIUrl":"10.1016/j.apor.2024.104274","url":null,"abstract":"<div><div>Through numerical modelling, the hydrodynamic performance of a novel wave energy converter-breakwater integrated system, consisting of a perforated breakwater and a heaving wave energy converter (HWEC) in the wave absorption chamber, is investigated. A method for modelling the Coulomb damping force (CDF) provided by the power take-off system is established to address the instability problem caused by the sudden change of the CDF when the motion direction of the HWEC changes. Under the representative wave condition (<span><math><mrow><mi>k</mi><mi>d</mi></mrow></math></span> = 1.76, where <span><math><mi>k</mi></math></span> is wave number and <span><math><mi>d</mi></math></span> is water depth), the working mechanism of the integrated system is clarified, the preferable HWEC hull shape is found, and the nondimensional relationships for determining the geometric parameters are obtained. In addition, by performing the simulation with the waves of <span><math><mrow><mi>k</mi><mi>d</mi></mrow></math></span> = 2.52 and <span><math><mrow><mi>k</mi><mi>d</mi></mrow></math></span> = 1.11, the limits of the geometric parameters are proposed. It is found that the asymmetric HWEC having a seaward straight corner and leeward curved corner is preferable to minimize wave reflection and capture appreciable wave energy. Under the tested condition, when the nondimensional PTO damping force ranges from 0.5 to 1.25 and the response amplitude operator of the HWEC is no less than 0.3, the capture width ratio of the integrated system will mostly exceed 0.3, and the reflected energy will be quite low.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104274"},"PeriodicalIF":4.3,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation on the influence of artificial island on reef hydrodynamics","authors":"Gancheng Zhu ,&nbsp;Bing Ren ,&nbsp;Hongjie Wen ,&nbsp;Pengzhi Lin","doi":"10.1016/j.apor.2024.104266","DOIUrl":"10.1016/j.apor.2024.104266","url":null,"abstract":"<div><div>The construction of artificial island can greatly change the reef hydrodynamics, leading to increased water level and wave height as well as changes in flow field distribution. These alterations can affect sediment transport on the reef, and increase the risk of overtopping and structure instability. A numerical model based on the Reynolds Averaged Navier-Stokes (RANS) equations and <em>k</em>-<em>ε</em> turbulence closure model was developed to investigate the influence of artificial island on reef hydrodynamics. The numerical model was validated against the experimental results of wave height, mean water level, and wave breaking morphology. Detailed flow field, wave height, and wave set-up in front of artificial island were further analyzed based on the validated model. After building the reef-top structure, the wave breaking and offshore currents at reef edge were amplified. The flow stratification and increase of the wave set-up were also found on the reef flat. Furthermore, we found the relationship between maximum flow velocities on the reef flat and incoming wave conditions could be characterized by two non-dimensional parameters: <span><math><mrow><msub><mrow><mrow><mo>|</mo></mrow><mover><mi>u</mi><mo>¯</mo></mover><mrow><mo>|</mo></mrow></mrow><mtext>max</mtext></msub><mo>/</mo><msqrt><mrow><mi>g</mi><mo>(</mo><mover><mi>η</mi><mo>¯</mo></mover><mo>+</mo><msub><mi>h</mi><mi>r</mi></msub><mo>)</mo></mrow></msqrt></mrow></math></span>, <span><math><mrow><mrow><mo>(</mo><mover><mi>η</mi><mo>¯</mo></mover><mo>+</mo><msub><mi>h</mi><mi>r</mi></msub><mo>)</mo></mrow><mo>/</mo><msub><mi>H</mi><mi>i</mi></msub></mrow></math></span>.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104266"},"PeriodicalIF":4.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Turbulence model adaptability at critical Reynolds numbers and applications in wake control via fairings","authors":"Yigang Gong ,&nbsp;Jiasong Wang","doi":"10.1016/j.apor.2024.104263","DOIUrl":"10.1016/j.apor.2024.104263","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The water-drop shaped fairings with varying shape angles are attached to a circular cylinder to achieve wake control and vortex suppression at critical Reynolds numbers. To ensure the capability of Reynolds averaged Navier–Stokes (RANS), detached eddy simulation (DES) and large eddy simulation (LES) models at the critical Reynolds number region, three representative turbulence models are employed: LES with &lt;span&gt;&lt;math&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; subgrid-scale (SGS) model, delayed DES model with improved wall-modeling capability (IDDES) and shear stress transport (SST) &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;ω&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; RANS model. These models are utilized to simulate flow around a circular cylinder at Reynolds number &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mtext&gt;Re&lt;/mtext&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The solver used in this paper is further developed based on the high-resolution algorithm platform for incompressible flow (HRAPIF). The comparative analysis of the results from the three turbulence models has been rigorously validated and investigated. An exhaustive examination of the mean flow field, Reynolds stresses, characteristic lengths, and instantaneous flow fields among the models reveals instructive insights. The IDDES and &lt;span&gt;&lt;math&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-LES models predict the hydrodynamic forces, the so-called ‘drag crisis’, alongside the pressure distribution and skin friction coefficient with high precision. The &lt;span&gt;&lt;math&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-LES model stands out for its superior accuracy, while the IDDES model is also a viable alternative, offering commendable accuracy with a reduced demand for mesh density. Subsequently, the IDDES model is selected for wake control calculations using fairings with five distinct shape angles (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mtext&gt;Re&lt;/mtext&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. In-depth comparisons to the bare cylinder and subcritical results reveal that the wake control effect varies at the critical Reynolds region. The fairing with a 30° shape angle substantially suppresses hydrodynamic forces. The lift coefficient experiences a remarkable decrease of approximately 96%, while the drag coefficient diminishes by about 90%. Concurrently, fairings with angles from 45° to 90° lead to reductions in drag coefficient of 11.6%, 10%, 3% and ","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104263"},"PeriodicalIF":4.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional numerical simulation of vortex-induced vibration of a free spanning submarine cable in uniform currents","authors":"Haidong Zhao ,&nbsp;Chao Wang ,&nbsp;Junjie Zhu ,&nbsp;Ping Dong ,&nbsp;Bing Ren ,&nbsp;Pengzhi Lin","doi":"10.1016/j.apor.2024.104268","DOIUrl":"10.1016/j.apor.2024.104268","url":null,"abstract":"<div><div>The free spanning submarine cable, a slender and flexible structure with a certain sag, exhibits unique vortex-induced vibration (VIV) characteristics in currents compared to offshore risers and submarine pipelines. To study the VIV of the cable, a three-dimensional numerical model based on the finite difference method (FDM) and the finite element method (FEM) is established. The large eddy simulation method is employed to close the turbulent motion equations in the hydrodynamic model, while the beam element method is used to solve the structural motion equations in the structural dynamic model. An analytical mapping method is adopted for the reconstruction of the structure surface in the fixed Cartesian fluid grids, and the immersed boundary method is used to deal with boundary conditions at fluid-solid interfaces. Since simulating VIV of a submarine cable with sag requires extensive local grid refinement near the cable's surface, a partition parallel algorithm with multi-GPU nodes is developed to enhance the computational efficiency, where the parallel efficiency of a single GPU can reach 80–90%. The numerical model is validated by a laboratory experiment on the VIV of a submarine cable, where the transverse response amplitudes and frequencies obtained by numerical simulation agree well with the experimental results. The streamwise vibration responses that are not measured in the experiment are analyzed by the numerical simulation. It is found that when the cable's equilibrium profile is deflected in the streamwise direction by the drag force, the streamwise vibration with the same frequency as the transverse vibration occurs, and the streamwise vibration amplitude increases with sag. The detailed flow field information provided by numerical simulation indicates that the size of the vortex structures gradually increases with the velocity, and the shape of the vortex structure has a strong correlation with the transverse vibration mode of the cable.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104268"},"PeriodicalIF":4.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experiments on the effect of wall distances for bubble collapse characteristics","authors":"Wei Xu ,&nbsp;Yuanyuan Zhao ,&nbsp;Guohui Zhao ,&nbsp;Fujian Zhao ,&nbsp;Xiuli Wang ,&nbsp;Chuan Wang","doi":"10.1016/j.apor.2024.104277","DOIUrl":"10.1016/j.apor.2024.104277","url":null,"abstract":"<div><div>At present, the energy released by bubble collapse can be used for the surface treatment of workpieces and can also be used to degrade pollutants. However, the mechanism of action between bubble collapse and a nearby wall has yet to be accurately explained. In order to grasp the relationship between the wall distance and collapse characteristics, the methods of spark discharge, high-speed photography, and pressure acquisition are used to study bubble shapes and the dynamic variation during pressure release with different wall distances in this paper. The results show that with the increasing of the distance <em>L</em>, the shape of a bubble changes from oblate to spherical and its collapse time shortens. The proportion of the total collapse time consumed by the slow collapse stage shows an increasing trend. In an experiment with two contractions, the time proportion of the slow collapse stage of the first contraction is much larger than that of the second contraction. The existence of the wall delays the collapse of the bubble. As the distance <em>L</em> increases, the bubble goes from undergoing one collapse to two collapses and then to one collapse again. The proportion of the duration of the slow collapse stage of the first contraction decreases rapidly, and the proportion of the slow collapse stage of the second contraction increases slowly, but the time proportion of second contraction decreases. When the distance <em>L</em> increases from 4.5 mm to 11 mm, the pressure received by the wall gradually decreases 28.19 MPa to 18.01 MPa. With an increase in the distance <em>S</em> from 0 to 8 mm, the maximum pressure received by the wall gradually decreases from 19.77 MPa to 9.37 MPa. The relationship found between the slow collapse stage (<em>t_a</em>), the second contraction (<em>t_b</em>), and the distance (<em>L</em>) can provide guidance for the effective application of the energy released by bubble collapse.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104277"},"PeriodicalIF":4.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An effective boundary element model to calculate the interaction between waves and flexible membrane","authors":"Chaofan Lv ,&nbsp;Shiming Yao ,&nbsp;Xizeng Zhao ,&nbsp;Hualong Luan ,&nbsp;Mengyu Li ,&nbsp;Kaiyuan Zheng ,&nbsp;Geng Qu","doi":"10.1016/j.apor.2024.104267","DOIUrl":"10.1016/j.apor.2024.104267","url":null,"abstract":"<div><div>Flexible membranes are widely used in marine engineering, but how to calculate their hydrodynamic performance under wave action remains a challenging problem. In this paper, a new model based on the eigenfunction expansion boundary element method (EEBEM) is proposed to calculate the wave-membrane interaction under two-dimensional conditions. A general dynamic boundary condition suitable for linear and arcuate membranes is established based on the membrane’s constitutive equations under cylindrical coordinates. This condition considers the dynamic tension and curvature of the membrane, and an integral expression for the dynamic tension is also derived. Subsequently, the dynamic boundary condition is transformed into a function of the velocity potential and applied to the EEBEM, overcoming the difficulty of the coupled solutions for the arcuate membrane’s motion and the flow field. Moreover, a generalized solution framework for wave-structure interaction is established by constructing a fully closed form of the water wave equations, which effectively shortens the modeling time and expands the application scope. After verifying the accuracy and effectiveness of the model, the hydrodynamic performance (wave force, membrane tension and wave transmission coefficient) and motion response of a submerged flexible membrane breakwater (SFMB) are investigated. The results demonstrate that the model exhibits high accuracy, which is beneficial for elucidating the mechanism of wave-membrane interaction and providing robust support for related research fields.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104267"},"PeriodicalIF":4.3,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A non-local formulation for simulating the fully nonlinear Serre–Green–Naghdi equations for a solitary wave interaction with a variable slope","authors":"T.S. Jang ,&nbsp;H.G. Sung ,&nbsp;Jinsoo Park","doi":"10.1016/j.apor.2024.104220","DOIUrl":"10.1016/j.apor.2024.104220","url":null,"abstract":"<div><div>In this paper, we simulate a solitary wave interaction with a variable slope with reflection on a vertical wall by integrating the <em>fully</em> nonlinear Serre–Green–Naghdi (SGN) equations. To this end, we first provide an iterative solution process for the SGN equations so that we can simulate a solitary wave propagating over variable bathymetry. For the purpose of the study, we examine two physical problems. The first is of a solitary wave interaction with a <em>constant</em> slope with reflection on a vertical wall. The simulated solutions are in good agreement with other numerical and experimental data, confirming the validity of the current work. The second is concerned with a perturbation of the first problem, where the constant slope of the first problem is varied; i.e., a variable slope is taken into account. We compare the simulated solutions of the two problems and observe the (physically realistic) effect of the variable slope on shoaling and reflection by the vertical wall.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104220"},"PeriodicalIF":4.3,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cumulative strain intelligent evaluation of marine soil from offshore wind farms based on enhanced machine learning","authors":"Zhishuai Zhang,&nbsp;Xinran Yu,&nbsp;Bo Han,&nbsp;Song Dai","doi":"10.1016/j.apor.2024.104265","DOIUrl":"10.1016/j.apor.2024.104265","url":null,"abstract":"<div><div>Accurate evaluation of cumulative strains in marine soils under long-term cyclic loading is essential for the design and safe operation of offshore wind turbines. This study proposes an enhanced machine learning model to predict the cumulative strain in marine soils subjected to cyclic loading. Cumulative strains of marine soils from five offshore wind farms under long-term cyclic loading were tested. Four prediction models for cumulative strains were developed and evaluated based on test results using the Back Propagation Neural Network (BP-NN), Random Forest (RF), Support Vector Regression (SVR), and eXtreme Gradient Boosting (XGBoost) models, each combined with the Particle Swarm Optimization (PSO) algorithm. The prediction model with the highest accuracy was further analyzed using the SHapley Additive exPlanations (SHAP) method. Results show that the RF and XGBoost algorithms have higher prediction accuracy, with R² values above 0.99, compared to the BP-NN and SVR models. Furthermore, dynamic triaxial test parameters significantly influence the cumulative strain predictions more than the soil properties. This study provides a more efficient method for cumulative strain assessment of marine soils under long-term cyclic loading.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104265"},"PeriodicalIF":4.3,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on ice-breaking characteristics of underwater explosion bubbles based on an effective coupled model","authors":"Ming He ,&nbsp;Jiale Yan ,&nbsp;Pengyu Lv ,&nbsp;Huiling Duan ,&nbsp;A-Man Zhang","doi":"10.1016/j.apor.2024.104259","DOIUrl":"10.1016/j.apor.2024.104259","url":null,"abstract":"<div><div>The use of underwater explosion bubbles for ice breaking represents an efficient technological advance that is critical for polar exploration. In this paper, we propose an effective numerical methodology for investigating this pertinent issue. By combining the advantages of peridynamics and the Eulerian finite element method, we establish a coupled model for investigating the integral ice-breaking characteristics of underwater explosion bubbles. Our model is capable of accurately simulating the formation of bifurcated ice cracks and capturing the evolution patterns of both ice cracks and crushed ice under various complex working conditions. When the extreme standoff parameter is set to zero, multiple crushed ice formations are effectively generated during contact explosion, and the changes in the height and width of this crushed ice exhibit a predominantly increasing trend over time. Furthermore, our results elucidate the destructive mechanism of the bubble jet on the ice structure. We find that when the initial bubble does not have a strong destructive effect, the jet’s impact becomes more pronounced. The conclusions from this study offer valuable technical support for real-world polar exploration problems.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104259"},"PeriodicalIF":4.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Online parameter identification and real-time manoeuvring prediction for a water-jet USV based on weighted multi-innovation prediction error method integrated with dynamic window strategy","authors":"Zaopeng Dong ,&nbsp;Baolin Wang ,&nbsp;Fei Tan ,&nbsp;Wenjie Zhou ,&nbsp;Yuanchang Liu","doi":"10.1016/j.apor.2024.104260","DOIUrl":"10.1016/j.apor.2024.104260","url":null,"abstract":"<div><div>Research on online parameter identification and real-time manoeuvring prediction for a class of water-jet unmanned surface vehicle (USV) is carried out in this paper. Utilizing actual sailing data from a water-jet USV, the weighted multi-innovation prediction error method integrated with dynamic window strategy is proposed to identify the manoeuvring parameters of the USV model online. Subsequently, real-time prediction of the water-jet USV's motion is achieved based on the established time-varying model. The thrust generation of water-jet propulsion system and the effect of rotational current on the USV's motion are analyzed simultaneously, and then a three-degree-of-freedom mathematical model is established for the water-jet USV equipped with two water-jet propulsion systems. Due to the weakening of the correction ability of the prediction error method in the later stage, an adaptive step factor with phase adjustment is designed to improve the response accuracy to the error innovation and maintain the algorithm's correction ability. Since the prediction error method updates the identification value using only a single innovation each time, incorporating multi-innovation theory enhances the utilization of historical data, allowing the algorithm to more accurately reflect the current state or trend. In order to fully consider the differences between data points, an adaptive weighting strategy is developed to assign weights according to the contribution of the data in the innovation window to USV modeling, so as to enhance the tracking performance of the time-varying parameters. Aiming at the outliers in the collected data, a dynamic innovation window strategy is designed, and then the data in this window is filtered by Quartile algorithm and the outliers are detected by local outlier factor, so that the window could contain more effective sailing state information. A large amount of actual test data analysis demonstrates that, the algorithm proposed in this paper could achieve more accurate online identification of water-jet USV model parameters and more precise real-time prediction of USV motion, which would provide strong support for safe navigation and efficient control of USV.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"153 ","pages":"Article 104260"},"PeriodicalIF":4.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424496","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}