Applied Ocean Research最新文献

{"title":"Real-time dynamic and structural behavior estimation of a steel lazy wave riser through finite-element-based digital twin and hull-motion sensor","authors":"","doi":"10.1016/j.apor.2024.104137","DOIUrl":"10.1016/j.apor.2024.104137","url":null,"abstract":"<div><p>A digital twin (DT) method is proposed to estimate the dynamic and structural behaviors of a Steel Lazy Wave Riser (SLWR) under environmental conditions. This method uses a 1D finite element (FE) riser model that can include various loads and boundary conditions measured from sensors. We selected a spread-moored Floating Production Storage and Offloading (FPSO) vessel to validate the proposed method, which hosts multiple Production and Injection SLWRs. Using the time-domain dynamics simulation program, we built a reference model considering the fully coupled FPSO with mooring lines and risers in various wind/wave/current conditions. The synthetic sensor data, which represents the motions and internal fluid density changes, were generated from the simulation of the reference model. Then, two riser DT models, the Top Oscillation Model (TOM) and the Two-Point Oscillation Model (TPOM), were built, considering only a single riser made of the 1D FE model. TOM employed vessel motions as boundary conditions while internal fluid density and ocean current could be inputted as external loads. TPOM incorporated an additional motion sensor attached to the riser. The motion data obtained from the reference model were first inputted into the respective riser DT models. Next, we further evaluated their performance with and without the estimated ocean currents and slugs of internal fluid. The time histories, spectra, and statistical data of displacements and stresses along the riser were systematically compared and analyzed for various test cases and environments. While the hull-motion sensor alone can provide practically acceptable results using the developed methodology, additional consideration of current load and internal fluid's density variation improves the overall riser monitoring performance. The present method can significantly reduce the number of sensors compared to traditional riser monitoring methods.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141952854","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 study of the bearing capacity of the hybrid skirted foundations in silty sand under combined loading","authors":"","doi":"10.1016/j.apor.2024.104129","DOIUrl":"10.1016/j.apor.2024.104129","url":null,"abstract":"<div><p>The evolution of offshore wind turbine (OWT) foundations has led to increased demands for enhanced load-bearing capabilities. Among the various solutions, the hybrid skirted foundation stands out for its notable resistance to lateral forces and rotational movement. This study employs numerical analysis to investigate the failure mechanisms and bearing capacities of hybrid skirted foundations in silty sand strata under combined vertical (<em>V</em>), lateral (<em>H</em>), and moment (<em>M</em>) loads, comparing the results with those from traditional bucket foundations. This study delves into the influence of the geometric dimensions of hybrid skirted foundations and the soil parameters of silty sand on their bearing capacity. A parameter study reveals that the hybrid skirted foundation exhibits exceptional lateral resistance, with the diameter of the upper mat significantly impacting failure mechanisms and bearing capacities. In silty sand, the moment bearing capacity of hybrid foundations shows a remarkable enhancement, increasing by 78% compared to that of traditional foundations. Furthermore, a preliminary computational framework is proposed to estimate the bearing performance of the hybrid skirted foundation in silty sand under combined loads.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141952853","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":"Corrigendum to “Experimental analysis on the risk of vortex ventilation and the free surface ventilation of marine propellers” [Applied Ocean Research, Volume 67, September 2017, Pages 201–212]","authors":"","doi":"10.1016/j.apor.2024.104116","DOIUrl":"10.1016/j.apor.2024.104116","url":null,"abstract":"","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0141118724002372/pdfft?md5=477e31fc03f849a3151878e2a3079e3d&pid=1-s2.0-S0141118724002372-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141851026","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":"Effects of wave breaking on moisture flux","authors":"","doi":"10.1016/j.apor.2024.104135","DOIUrl":"10.1016/j.apor.2024.104135","url":null,"abstract":"<div><p>Wave breaking is a ubiquitous phenomenon in ocean dynamics, serving as a critical conduit for the exchange of momentum, heat, and energy between the atmosphere and the ocean. Although its vital role in air-sea moisture exchange is widely acknowledged, quantifying its exact impact on moisture flux remained quite challenging due to data limitations and the inherently turbulent nature of the process. To overcome these challenges, we construct a comprehensive 10-year global dataset that incorporates multiple breaking wave variables, informed by statistical breaking theories, to capture the intricacies of the breaking process and its consequential effects. We then employ a stacked machine learning model to elucidate the complex relationships between wave breaking and moisture flux. The performance of our stacked model, which is enriched with breaking wave variables, is validated against the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis data (ERA5). The results offer excellent predictions and highlight the importance of breaking-wave-related variables in regulating moisture flux, thereby substantiating the integral role of wave breaking in modulating air-sea interactions and moisture transport.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141951278","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 microstructural investigation on hydraulic conductivity of calcareous clay","authors":"","doi":"10.1016/j.apor.2024.104133","DOIUrl":"10.1016/j.apor.2024.104133","url":null,"abstract":"<div><p>Calcareous clay is an important fine-grained component of the reclaimed island foundation. It is commonly incorporated with calcareous sand to form a mixture interlayer. Hydraulic conductivity is a crucial engineering property of foundation soil significantly influenced by fine particle composition. Thus, to investigate the role of calcareous clay in the seepage of sand-clay mixture, a series of consolidation tests and hydraulic conduction tests were conducted on calcareous clay and calcareous sand-clay mixture, and the effects of hydraulic gradient, void ratio, calcareous sand content and particle size on the hydraulic conduction were discussed. The test results indicated that the hydraulic conductivity of calcareous clay was maintained at the order of magnitude of 10⁻⁶ cm/s, and the implications of hydraulic gradient and void ratio were minimal. When mixed with the coarse calcareous sand, with the increase of sand content, the hydraulic conductivity of the sand-clay mixture was initially held at 10⁻⁶ cm/s, subsequently escalated rapidly to 10⁻³ cm/s when the sand content was between 30 % ∼ 80 %, and finally stabilized at this order of magnitude when the sand content exceeded 80 %. Based on this phenomenon, a three-stage model saparated by two critical ratios of calcareous sand-clay mixture seepage was proposed: no skeleton stage, partial skeleton stage and complete skeleton stage. The inference was verified by the stability of the hydraulic conduction results in the gradient reversal test. Furthermore, to analyze the seepage performance from the microstructure, several field emission scanning electron microscope tests were carried out after hydraulic conduction, and the pore size distribution was quantified. The incorporation of calcareous sand led to the transformation of the peak pore in the mixture from nanopores with the pore size less than 0.1 μm to macropores with the pore size exceeding 10 μm. Additionally, the correlation between the unimodal/bimodal model of pore distribution and the three-stage model of mixture seepage was established, and a microscopic explanation of the hydraulic conduction rate and stability of calcareous sand-caly mixture was provided.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141951279","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 study on trenching performances of the underwater jet flow for submarine cable laying","authors":"","doi":"10.1016/j.apor.2024.104140","DOIUrl":"10.1016/j.apor.2024.104140","url":null,"abstract":"<div><p>Submarine cables are becoming a primary solution for transmitting electricity between the mainland and the islands. Underwater trenching using the jet flow is widely employed in cable laying engineering. The numerical studies on underwater trenching performance can provide valuable information to practical engineering for enhancing operational efficiency and reducing construction costs. In this study, a numerical model based on the commercial computational fluid dynamics software Flow3D® was established and validated by corresponding experimental data. It was found that the jet flow velocity significantly influences the trench width and depth and has minor effects on the ramp slope. An increase in the trench width can be observed as the jet-flow velocity increases. The variation in the trench depth depends on the back siltation caused by the variation of the jet-flow velocity. In addition, the nozzle motion also affects the trench width and depth, decreasing as the translation velocity of the jet nozzle increases.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141951277","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 study of wet-deck slamming characteristic for a trimaran in regular head waves","authors":"","doi":"10.1016/j.apor.2024.104136","DOIUrl":"10.1016/j.apor.2024.104136","url":null,"abstract":"<div><p>Wet deck may suffer from strong slamming effects when sailing under severe sea conditions, which could damage it locally and compromise the structural integrity of trimarans. The wet-deck slamming characteristic for trimaran sailing in head waves is studied in this work using both experimental and numerical simulation methods. We found that the negative pressure occurred at the front of the wet deck, which is caused by the wet deck exit from the wave crest. Regarding the spatial distribution in longitudinal, the slamming behaviour is more severe at the front part of the wet deck, as the relative vertical impact velocity decreased from the front to the back part of it. Simultaneously, the wet-deck slamming is more severe under the short-wave condition. Regarding the spatial distribution in lateral, we found that the water-entry of the main hull could cause the wet-deck slamming pressure near the outrigger larger than that of the main hull. Moreover, the wet deck has been divided into three regions according to their different lateral distribution characteristics of the wet-deck slamming. These results can provide a better understanding of the wet-deck slamming characteristics when trimaran sailing in waves, which can be considered in future designs for the trimaran.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141959947","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":"Machine learning models applied to altimetry era tide gauge and grid altimetry data for comparative long-term trend estimation: A study from Shikoku Island, Japan","authors":"","doi":"10.1016/j.apor.2024.104132","DOIUrl":"10.1016/j.apor.2024.104132","url":null,"abstract":"<div><p>Estimation of sea level trends is essential for understanding sea level rise dynamics. In this study, the performance of traditional Ordinary Least Squares (OLS) linear trend forecasting is compared with modern machine learning techniques, specifically Random Forests (RF) and Least Squares Support Vector Machines (LS-SVM).These methods are applied to 50 years of long-term tide gauge (TG) data from six tide gauge stations off the coast of Shikoku Island, Japan, and CMEMS Grid Altimetry data from 1993 to the present. The analysis uses OLS, RF, and LS-SVM to estimate trends from both data sets and compares the results. The objective is to determine the consistency and accuracy of RF and LS-SVM methods compared to the OLS method. The results indicate that machine learning algorithms (LS-SVM) effectively estimate sea level trends, offering potential improvements in precision for both long-term and medium-term analyses. Shikoku Island's coastal sea level trend is determined as 2.91±1.44 mm/yr using TG data and 3.00±1.52 mm/yr using CMEMS Grid Altimeter data with the OLS approach. Using the LS-SVM approach, the trend is found as 2.96±1.58 mm/yr with TG data and 3.02±1.60 mm/yr with CMEMS Grid Altimetry data. The novelty of this study lies in its thorough comparison of traditional and machine learning approaches for sea level trend estimation, providing valuable insights for future predictions of the sea level rise.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141959946","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":"Evaluating scale effects in the modeling of buried offshore pipes in Chabahar carbonate sand using centrifuge testing","authors":"","doi":"10.1016/j.apor.2024.104130","DOIUrl":"10.1016/j.apor.2024.104130","url":null,"abstract":"<div><p>A major instability mode of buried offshore pipes, used to transport hydrocarbon materials, extracted from reservoirs, discovered at the seabed, is \"upheaval buckling\". Although research on factors that affect the buckling of buried pipes is extensive, there are still uncertainties about the effects of the soil particle size in centrifuge models. This research has used 3 varying-diameter pipes and 3 types of carbonate soils with different grain sizes, to study such effects in 4 axes utilizing a centrifuge device. According to the results, in the \"modeling of models\" tests with similar soils, scale effect is ignorable if the ratio of pipe diameter to the average soil-grain size (<span><math><mrow><mi>D</mi><mo>/</mo><msub><mi>d</mi><mn>50</mn></msub></mrow></math></span>) is greater than 40, but if different grain-size sands are used, the scale effect is clearly evident in the results assuming that the pipe geometry is kept constant at model and prototype scales. It seems that the common criterion used by past researches for <span><math><mrow><mi>D</mi><mo>/</mo><msub><mi>d</mi><mn>50</mn></msub></mrow></math></span> has not been enough alone, and minimizing the scale effect needs adding another criterion such as<span><math><mrow><mspace></mspace><mi>L</mi><mo>/</mo><msub><mi>d</mi><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></mrow></math></span>, which is the ratio of the shear band length to the maximum soil-particle size. Results have also shown that increasing the pipe's burial depth will make the particle-size effect more obvious, but increasing the soil's relative density will make the mentioned effect less evident on the peak dimensionless breakout factor (<span><math><msub><mi>N</mi><mrow><mi>u</mi><mo>.</mo><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span>).</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141731971","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":"On the complex mode shapes and natural frequencies of clamped-clamped fluid-conveying pipe","authors":"","doi":"10.1016/j.apor.2024.104113","DOIUrl":"10.1016/j.apor.2024.104113","url":null,"abstract":"<div><p>In the present study, the closed-form expression for complex mode shapes of a fluid-conveying pipe using Timoshenko beam theory is developed for the first time. By applying the method of separation of variables, the complex mode shapes and eigenvalues are obtained. To the best knowledge of the authors, there is no study carried out on the complex eigenvalue problem for vibration analysis of the Timoshenko fluid-conveying pipes. Given this oversight, in this study the effects of fluid velocity on the imaginary and real parts of the mode shapes and natural frequencies of a clamped-clamped fluid-conveying pipe are investigated. The results show that for very low fluid velocities, the first and the second mode shapes are similar to that of an equivalent beam. For high fluid velocities, the first mode shape experiences some deviation so that it looks like the second mode shape of a pipe having very low fluid velocity. The results show that fluid flow in the pipeline effectively reduces its bending moment as well as the energy of vibration. In addition, the nodal points corresponding to the second mode are replaced with quasi-node points.</p></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728994","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}