Ocean Engineering最新文献

{"title":"Dynamic numerical simulation of ice-propeller milling based on GPU parallel computing","authors":"Chenxu Gu ,&nbsp;Chengjie Cao ,&nbsp;Yongjin Li ,&nbsp;Liyu Ye ,&nbsp;Chao Wang","doi":"10.1016/j.oceaneng.2024.119728","DOIUrl":"10.1016/j.oceaneng.2024.119728","url":null,"abstract":"<div><div>To integrate high-performance GPU parallel computing with the peridynamics method and enhance the computational efficiency of numerical simulations for ice-propeller milling, thus providing better data support for the design of propellers in ice-covered areas, a GPU-based parallel peridynamics computational approach was developed on CUDA in this study. The approach was built upon the bond-based peridynamics theory and CUDA programming framework, and its validity was confirmed using test cases involving an airfoil cutting ice and an ice ball impacting a rigid wall. A corresponding three-dimensional GPU parallel computational program was created for the ice-propeller milling process, and the computational code was optimized, resulting in a 24-fold increase in computational efficiency. Utilizing the high-performance computational code, the influence of sea ice elastic modulus and propeller pitch on the mechanical performance of the blades was investigated. The computational results revealed that the ice loads on the blades increased with rising elastic modulus and decreased with increasing pitch, and a larger pitch led to more sea ice being milled away.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119728"},"PeriodicalIF":4.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660526","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":"Oscillatory responses of a spatially random seabed in the vicinity of structures: Validation and application of the integrated CFD-SFEM","authors":"Bin Zhu ,&nbsp;Yuan Sun ,&nbsp;Tao Wang ,&nbsp;Pinqiang Mo ,&nbsp;Yunrui Han ,&nbsp;Yubin Ren ,&nbsp;Jiabo Li","doi":"10.1016/j.oceaneng.2024.119733","DOIUrl":"10.1016/j.oceaneng.2024.119733","url":null,"abstract":"<div><div>A comprehensive examination of the wave-induced oscillatory response of seabeds around structures is of great significance for ensuring the safe operation of marine engineering projects and enhancing the efficiency of marine resource development. Soil properties in nature exhibit spatial variability due to various geological processes, which should be considered in seabed stability analysis. An integrated CFD-SFEM is proposed for spatially heterogeneous seabeds, incorporating multi-physical solvers for nonlinear wave motion and poroelastic seabed response within a unified framework through a one-way coupling procedure. The wave sub-model for nonlinear fluid flow is based on RANS equations, with an internal wave-maker and absorbing layers realized by employing a momentum source function and damping source terms. The spatially heterogeneous seabed sub-model is based on Biot's poroelastic theory and the random field method. We have implemented the integrated model and automated the iterative algorithm for MCS using MATLAB codes, assisted by the LiveLink platform. The proposed method has been validated from various perspectives and applied to a study of soil response around a partially buried pipeline to demonstrate its practical utility. This study offers a novel framework and perspective for the probabilistic evaluation of oscillatory responses in spatially varied seabeds surrounding structures.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119733"},"PeriodicalIF":4.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660523","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":"Hydrodynamic performance and energy efficiency of an undulating fin based on the composite motion of oscillation and pitch","authors":"Qian Yin ,&nbsp;Minghai Xia ,&nbsp;Zhangmao Hu ,&nbsp;Jinqiao He ,&nbsp;Zirong Luo","doi":"10.1016/j.oceaneng.2024.119707","DOIUrl":"10.1016/j.oceaneng.2024.119707","url":null,"abstract":"<div><div>Fish-like robots have become underwater vehicles with broad application prospects, owing to their flexibility and adaptability. Inspired by the swimming motion of fish, an undulating fin with composite motion is proposed in this study. The composite motion is a combination of oscillation and pitch perpendicular to and parallel to the horizontal direction, respectively. First, the kinematic and dynamic modes of the motion mechanism in the free propulsive mode are established with variable locomotive parameters, such as the oscillating frequency and deflection angle. The hydrodynamic performance of the undulating fin is then investigated through analyses of the force mechanism, propulsive velocity, non-dimensional number, and vortex flow using the dynamic mesh method. The energy efficiency of the composite motion of undulating fin is compared with that of a simple oscillating motion. Finally, experimental measurements of an undulating-fin robot prototype are conducted. The results show that the underwater robot accelerates to a maximum velocity of 0.54 m/s with a frequency of 2.5 Hz. Owing to the composite motion, alternating high and low-velocity regions occur in the surrounding fluid of the undulating fin. The highest energy efficiency is 0.88 with a frequency of 2.0 Hz, and the maximum improvement is 10.1% compared with the simple oscillating motion. A streamwise central jet is formed with vortices shedding into the wake flow, which generates a thrust force with two peaks and troughs in one cycle. The negative and positive vorticities correspond to the alternation of the pressure distribution. The experimental measurements demonstrate the propulsive velocity and force are consistent with the numerical simulation. The composite motion with a higher Strouhal number reflects the considerable instability of the flow.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119707"},"PeriodicalIF":4.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660535","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":"Steady-state response of an infinite, free floating ice sheet to a moving load at constant velocity","authors":"J. Qiu ,&nbsp;Z.Q. Wang","doi":"10.1016/j.oceaneng.2024.119627","DOIUrl":"10.1016/j.oceaneng.2024.119627","url":null,"abstract":"<div><div>This study investigates the steady-state response of a thin elastic plate floating on the surface of an infinitely deep compressible fluid to a moving line load. The load travels at a constant speed along the axial direction in the one-dimensional model. A steady-state solution was theoretically established for the moving load, and the expressions for the vertical displacement and pressure, and velocity in the fluid were explicitly determined. Integral transforms and asymptotic methods were used to derive a semi-analytical solution for the steady-state response, and the influence of the plate thickness and velocity of the moving load on the fluid domain pressure and the structure interaction response of the plate is thoroughly discussed. Numerical analysis results indicate that when the moving force traverses a large coupled elastic plate at a constant velocity, a portion of the response gradually evolves into a steady-state condition. This study uniquely addresses the steady-state response of an ice sheet in contact with a compressible fluid under subsonic conditions, a less explored area in existing literature. The findings have significant implications for the design and safety of infrastructure in Arctic regions.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119627"},"PeriodicalIF":4.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660545","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":"Experimental and numerical simulation study of drag reduction on AUV grooved surfaces","authors":"Siqi Zhang ,&nbsp;Xiaoyi Wu ,&nbsp;Shan Ma ,&nbsp;Ziqian Wang ,&nbsp;Zhuo Sun ,&nbsp;Ming Hu","doi":"10.1016/j.oceaneng.2024.119610","DOIUrl":"10.1016/j.oceaneng.2024.119610","url":null,"abstract":"<div><div>In the study of hydrodynamic performance of Autonomous Underwater Vehicles (AUVs), drag reduction is a crucial aspect that can significantly lower energy consumption and enhance operational range. Groove drag reduction, a form of passive drag reduction technology, is widely employed across various fields due to its simple structure and broad applicability. Implementing grooved surfaces on AUVs is an effective solution for reducing drag. This paper investigates the resistance of AUVs with grooved surfaces through experimental methods and comparative testing. A full-scale numerical simulation utilizing two-phase flow is also conducted, revealing that the resistance reduction results align closely with the trends observed in model tests. The maximum drag reduction achieved in the experiments is 8.13%. While discrepancies exist between numerical and experimental results, the overall physical principles remain consistent.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119610"},"PeriodicalIF":4.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660595","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":"Wingsail performance in unsteady atmospheric surface layer winds","authors":"Clément Bouhourd,&nbsp;Laurent Perret,&nbsp;Carlo Cossu","doi":"10.1016/j.oceaneng.2024.119653","DOIUrl":"10.1016/j.oceaneng.2024.119653","url":null,"abstract":"<div><div>The performance of wind propulsion systems is evaluated in unsteady inhomogeneous winds with tools that are routinely used to predict the performance of wind turbines and which give access to the unsteady aerodynamic forces acting on the wingsail. A rigid wingsail exposed to a realistic atmospheric surface layer wind is used as a testbed. For this case, we show that standard deviations of the aerodynamic driving force are larger than 15%–20% of the mean values when the true wind velocity is larger than the ship speed. We also show that the mean aerodynamic driving forces computed by averaging the unsteady driving forces are only slightly smaller than the ones computed on the mean wind despite the strongly nonlinear dependence of the unsteady forces on the wind velocity and direction.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119653"},"PeriodicalIF":4.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660521","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":"Analyzing AIS and wave hindcast data for global wave scatter diagrams with seasonality","authors":"Wataru Fujimoto,&nbsp;Kinya Ishibashi,&nbsp;Tingyao Zhu","doi":"10.1016/j.oceaneng.2024.119647","DOIUrl":"10.1016/j.oceaneng.2024.119647","url":null,"abstract":"<div><div>Global scatter diagrams are used to estimate possible ship motions in a specified route and are required for comprehensive cargo-loading considerations of merchant ships. This study aims to update global wave scatter diagrams using the latest wave hindcast and Automatic Identification System (AIS) data. The AIS data for over 7500 merchant ships were collected between 2015 and 2022. The wave hindcast data ECMWF Reanalysis v.5 (ERA5), preferred for its recent coverage, were adjusted based on CCI satellite data. The duration of the AIS data is much shorter than the design lifetime of merchant ships, which is generally 25 years. This study found almost linear relationships between the maximum significant wave heights in storms and the generalized extreme value (GEV) parameters representing the distribution of encountered significant wave heights, with adjustments made for seasonality and tropical cyclones. By simulating the parameters based on these relationships and the wave hindcast data over 25 years, the encountered significant wave height distributions over 25 years were obtained. The results indicated a reduction in extremely significant wave heights compared with the BMT-GWS, in agreement with previous studies. This study also found that the difference in the wave period distribution between natural and encountered sea states was small in most sea areas for all significant wave height levels. Taking advantage of the abundant data volume of ERA5, this study adopted an empirical distribution of the wave period conditioned by the significant wave height. The novelty of this study is that we obtained wave scatter diagrams globally by month to consider the seasonal effect in detail and evaluated the confidence interval of the encountered wave height in its probability tail. In addition, this study quantifies the uncertainty of the wave height distribution by Monte Carlo simulation, which is not within the scope of previous studies on wave scatter diagrams based on the significant wave heights encountered by merchant ships around the world.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119647"},"PeriodicalIF":4.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660598","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":"Numerical simulation of the relationship between steam flow excitation characteristics and coverage on the governing stage of marine steam turbine","authors":"Tao Sun ,&nbsp;Yingzhuo Liu ,&nbsp;Zhenlai Ma ,&nbsp;Peng Shu ,&nbsp;Zhenyu Ye","doi":"10.1016/j.oceaneng.2024.119526","DOIUrl":"10.1016/j.oceaneng.2024.119526","url":null,"abstract":"<div><div>“Coverage” refers to the disparity between the inlet height of the rotor blade and the outlet height of the nozzle blade in the governing stage of steam turbines. The adoption of partial admission operating mode exacerbates the instability of the internal flow field. Therefore, investigating the influence of coverage on the governing stage's internal flow field is of paramount importance. In this regard, numerical simulations are conducted to analyze the internal flow field of the governing stage under partial admission operation, aiming to explore the impact of coverage variation. The results show that coverage significantly affects the excitation characteristics. The steam flow excitation force of the governing stage rotor blades under partial admission will fluctuate periodically in the flow zone of the steam flow. There will be a sudden increase in pressure at the rotating outlet end, particularly at the rotation frequency, two times the rotation frequency, and the blade pass frequency, exhibiting substantial amplitude. Adjusting the coverage to reduce the amplitude of the excitation force at the rotation frequency will result in an increase in the amplitude at the blade pass frequency. This study provides a reference for the design of the coverage of marine steam turbines.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119526"},"PeriodicalIF":4.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660596","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":"Parametric analysis of pseudo-shakedown behaviour of plates under repeated impacts","authors":"Xu He,&nbsp;C. Guedes Soares","doi":"10.1016/j.oceaneng.2024.119675","DOIUrl":"10.1016/j.oceaneng.2024.119675","url":null,"abstract":"<div><div>This article conducts a parametric analysis to investigate how dynamic material properties, plate dimensions, and boundary conditions affect the pseudo-shakedown behaviour of plates under repeated impacts. Validated numerical simulation methods are employed for this analysis. Different constitutive equations accounting for strain rate effects are used to vary dynamic material properties. Plate dimensions are varied in terms of aspect ratios and plate thicknesses. Various boundary conditions, including fully fixed boundary and conditions allowing in-plane sliding, are considered. The analysis reveals that strain rate effects, plate dimensions and boundary conditions significantly affect the pseudo-shakedown response to repeated impacts. A discussion is made on the challenges and considerations in accurately modelling strain rate effects and boundary conditions in numerical simulations. The findings of this parametric analysis are useful for designing ship plates to withstand repeated impacts, when incorporating pseudo-shakedown concept in design strategies.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119675"},"PeriodicalIF":4.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660519","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":"Hydrodynamic characteristics and internal flow field of a perforated fishing vessel under wave conditions","authors":"Xi Zhang ,&nbsp;Junjun Lv ,&nbsp;Dachuan He ,&nbsp;Ke Wang ,&nbsp;Ying Liu ,&nbsp;Jie Zhi","doi":"10.1016/j.oceaneng.2024.119611","DOIUrl":"10.1016/j.oceaneng.2024.119611","url":null,"abstract":"<div><div>This research focuses on an innovative design of a perforated fishing vessel, aiming to precisely and efficiently evaluate its hydrodynamic performance and the characteristics of its internal flow fields. Initially, the boundary element method is employed to tackle the challenge of hydrodynamic responses in structures with arbitrary openings, quantifying added mass, damping effects, and dynamic responses under various filling scenarios. This sets a foundation for assessing structural stability. Subsequently, using the CFD method, based on the Navier–Stokes equations, a deep exploration into the mechanisms of how fluid viscosity and nonlinear effects influence the flow fields inside and outside the culture compartments is conducted. This reveals the impact of detailed flow field features on the fish welfare of fishing vessel design. The CFD method implemented the forced motion of the aquaculture fishing vessel based on FLUENT UDF, with the specific parameters of the moving boundary conditions determined by the results of the BEM method. The frequency-domain results show that the heave motion response is significantly greater than the sway. Compared with the isolated heave flow field results, the coupling heave-roll motion causes obvious vortex phenomena in the fluid on both sides of the perforated fishing vessel.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"314 ","pages":"Article 119611"},"PeriodicalIF":4.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660522","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}