Ocean Systems Engineering-An International Journal最新文献_第4页

Numerical investigation of the effect of the location of stern planes on submarine wake flow 尾平面位置对潜艇尾流影响的数值研究

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Ocean Systems Engineering-An International Journal Pub Date : 2020-01-01 DOI: 10.12989/OSE.2020.10.3.289

S. M. Beigi, A. Shateri, M. D. Manshadi

引用次数: 0

Time-domain coupled analysis of curved floating bridge under wind and wave excitations 风浪作用下弯曲浮桥时域耦合分析

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Ocean Systems Engineering-An International Journal Pub Date : 2020-01-01 DOI: 10.12989/OSE.2020.10.4.399

Chungkuk Jin, Moo-Hyun Kim, W. Chung, Do-Soo Kwon

{"title":"Time-domain coupled analysis of curved floating bridge under wind and wave excitations","authors":"Chungkuk Jin, Moo-Hyun Kim, W. Chung, Do-Soo Kwon","doi":"10.12989/OSE.2020.10.4.399","DOIUrl":"https://doi.org/10.12989/OSE.2020.10.4.399","url":null,"abstract":"A floating bridge is an innovative solution for deep-water and long-distance crossing. This paper presents a curved floating bridge's dynamic behaviors under the wind, wave, and current loads. Since the present curved bridge need not have mooring lines, its deep-water application can be more straightforward than conventional straight floating bridges with mooring lines. We solve the coupled interaction among the bridge girders, pontoons, and columns in the time-domain and to consider various load combinations to evaluate each force's contribution to overall dynamic responses. Discrete pontoons are uniformly spaced, and the pontoon’s hydrodynamic coefficients and excitation forces are computed in the frequency domain by using the potential-theory-based 3D diffraction/radiation program. In the successive time-domain simulation, the Cummins equation is used for solving the pontoon's dynamics, and the bridge girders and columns are modeled by the beam theory and finite element formulation. Then, all the components are fully coupled to solve the fully-coupled equation of motion. Subsequently, the wet natural frequencies for various bending modes are identified. Then, the time histories and spectra of the girder's dynamic responses are presented and systematically analyzed. The second-order difference-frequency wave force and slowly-varying wind force may significantly affect the girder's lateral responses through resonance if the bridge’s lateral bending stiffness is not sufficient. On the other hand, the first-order wave-frequency forces play a crucial role in the vertical responses.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"10 1","pages":"399-414"},"PeriodicalIF":0.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66504469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A comparative study of different active heave compensation approaches 不同主动升沉补偿方法的比较研究

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Ocean Systems Engineering-An International Journal Pub Date : 2020-01-01 DOI: 10.12989/OSE.2020.10.4.373

Shrenik Zinage, Abhilash Somayajula

引用次数: 6

Sloshing suppression by floating Baffle 浮动挡板抑制晃动

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Ocean Systems Engineering-An International Journal Pub Date : 2019-12-01 DOI: 10.12989/OSE.2019.9.4.409

H. Kang, Ummul Ghafir Md Arif, K. Kim, Moo-Hyun Kim, Yujie Liu, K. Lee, Y. Wu

{"title":"Sloshing suppression by floating Baffle","authors":"H. Kang, Ummul Ghafir Md Arif, K. Kim, Moo-Hyun Kim, Yujie Liu, K. Lee, Y. Wu","doi":"10.12989/OSE.2019.9.4.409","DOIUrl":"https://doi.org/10.12989/OSE.2019.9.4.409","url":null,"abstract":". Sloshing is a phenomenon which may lead to dynamic stability and damages on the local structure of the tank. Hence, several anti-sloshing devices are introduced in order to reduce the impact pressure and free surface elevation of liquid. A fixed baffle is the most prevailing anti-sloshing mechanism compared to the other methods. However, the additional of the baffle as the internal structure of the LNG tank can lead to frequent damages in long-term usage as this structure absorbs the sloshing loads and thus increases the maintenance cost and downtime. In this paper, a novel type of floating baffle is proposed to suppress the sloshing effect in LNG tank without the need for reconstructing the tank. The sloshing phenomenon in a membrane type LNG tank model was excited under sway motion with 30% and 50% filling condition in the model test. A regular motion by a linear actuator was applied to the tank model at different amplitudes and constant period at 1.1 seconds. Three pressure sensors were installed on the tank wall to measure the impact pressure, and a high-speed camera was utilized to record the sloshing motion. The floater baffle was modeled on the basis of uniform-discretization of domain and tested based on parametric variations. Data of pressure sensors were collected for cases without- and with-floating baffle. The results indicated successful reduction of surface run-up and impulsive pressure by using a floating baffle. The findings are expected to bring significant impacts towards safer sea transportation of LNG.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"9 1","pages":"409-422"},"PeriodicalIF":0.9,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49474284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Response of triceratops to impact forces: numerical investigations 三角龙对撞击力的反应：数值研究

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Ocean Systems Engineering-An International Journal Pub Date : 2019-12-01 DOI: 10.12989/OSE.2019.9.4.349

S. Chandrasekaran, R. Nagavinothini

{"title":"Response of triceratops to impact forces: numerical investigations","authors":"S. Chandrasekaran, R. Nagavinothini","doi":"10.12989/OSE.2019.9.4.349","DOIUrl":"https://doi.org/10.12989/OSE.2019.9.4.349","url":null,"abstract":"Triceratops is one of the new generations of offshore compliant platforms suitable for ultra-deepwater applications. Apart from environmental loads, the offshore structures are also susceptible to accidental loads. Due to the increase in the risk of collision between ships and offshore platforms, the accurate prediction of structural response under impact loads becomes necessary. This paper presents the numerical investigations of the impact response of the buoyant leg of triceratops usually designed as an orthogonally stiffened cylindrical shell with stringers and ring frames. The impact analysis of buoyant leg with a rectangularly shaped indenter is carried out using ANSYS explicit analysis solver under different impact load cases. The results show that the shell deformation increases with the increase in impact load, and the ring stiffeners hinder the shell damage from spreading in the longitudinal direction. The response of triceratops is then obtained through hydrodynamic response analysis carried out using ANSYS AQWA. From the results, it is observed that the impact load on single buoyant leg causes periodic vibration in the deck in the surge and pitch degrees of freedom. Since the impact response of the structure is highly affected by the geometric and material properties, numerical studies are also carried out by varying the strain rate, and the location of the indenter and the results are discussed.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"9 1","pages":"349"},"PeriodicalIF":0.9,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47946485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Optimization of a horizontal axis marine current turbine via surrogate models 基于代理模型的水平轴海流轮机优化

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Ocean Systems Engineering-An International Journal Pub Date : 2019-06-21 DOI: 10.12989/OSE.2019.9.2.111

K. Thandayutham, E. Avital, N. Venkatesan, A. Samad

{"title":"Optimization of a horizontal axis marine current turbine via surrogate models","authors":"K. Thandayutham, E. Avital, N. Venkatesan, A. Samad","doi":"10.12989/OSE.2019.9.2.111","DOIUrl":"https://doi.org/10.12989/OSE.2019.9.2.111","url":null,"abstract":"Flow through a scaled horizontal axis marine current turbine was numerically simulated after validation and the turbine design was optimized. The computational fluid dynamics (CFD) code Ansys-CFX 16.1 for numerical modeling, an in-house blade element momentum (BEM) code for analytical modeling and an in-house surrogate-based optimization (SBO) code were used to find an optimal turbine design. The blade-pitch angle (θ) and the number of rotor blades (NR) were taken as design variables. A single objective optimization approach was utilized in the present work. The defined objective function was the turbine’s power coefficient (CP). A 3x3 full-factorial sampling technique was used to define the sample space. This sampling technique gave different turbine designs, which were further evaluated for the objective function by solving the Reynolds-Averaged Navier–Stokes equations (RANS). Finally, the SBO technique with search algorithm produced an optimal design. It is found that the optimal design has improved the objective function by 26.5%. This article presents the solution approach, analysis of the turbine flow field and the predictability of various surrogate based techniques.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"9 1","pages":"111-133"},"PeriodicalIF":0.9,"publicationDate":"2019-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44218445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Reliability sensitivity analysis of dropped object on submarine pipelines 海底管道掉落物可靠性灵敏度分析

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Ocean Systems Engineering-An International Journal Pub Date : 2019-06-01 DOI: 10.12989/OSE.2019.9.2.135

Sina Taghizadeh Edmollaii, P. Edalat, Mojtaba Dyanati

引用次数: 10

Numerical calculation and experiment of a heaving-buoy wave energy converter with a latching control 带闭锁控制的升沉浮标波浪能转换器的数值计算与实验

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Ocean Systems Engineering-An International Journal Pub Date : 2019-03-01 DOI: 10.12989/OSE.2019.9.1.001

Jeongrok Kim, I. Cho, Moo-Hyun Kim

引用次数: 7

Irregular frequency effects in the calculations of the drift forces 漂移力计算中的不规则频率效应

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Ocean Systems Engineering-An International Journal Pub Date : 2019-01-01 DOI: 10.12989/OSE.2019.9.1.097

Yujie Liu, J. Falzarano

引用次数: 1

A study on response analysis of submerged floating tunnel with linear and nonlinear cables 线性与非线性索下沉浮隧道响应分析研究

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Ocean Systems Engineering-An International Journal Pub Date : 2019-01-01 DOI: 10.12989/OSE.2019.9.3.219

Poorna Chandra Rao Yarramsetty, V. Domala, P. Poluraju, R. Sharma

{"title":"A study on response analysis of submerged floating tunnel with linear and nonlinear cables","authors":"Poorna Chandra Rao Yarramsetty, V. Domala, P. Poluraju, R. Sharma","doi":"10.12989/OSE.2019.9.3.219","DOIUrl":"https://doi.org/10.12989/OSE.2019.9.3.219","url":null,"abstract":"This paper presents the comparison between SFT response with linear and nonlinear cables. The dynamic response analysis of submerged floating tunnel (SFT) is presented computationally with linear and nonlinear tension legs cables. The analysis is performed computationally for two wave directions one at 90 degrees (perpendicular) to tunnel and other at 45 degrees to the tunnel. The tension legs or cables are assumed as linear and nonlinear and the analysis is also performed by assuming one tension leg or cable is failed. The Response Amplitude Operators (RAO‟s) are computed for first order waves, second order waves for both failure and non-failure case of cables. For first order wavesthe SFT response is higher for sway and heave degree of freedom with nonlinear cables as compared with linear cables. For second order waves the SFT response in sway degree of freedom is bit higher response with linear cables as compared with nonlinear cables and the SFT in heave degree of freedom has higher response at low time periods with nonlinear cables as compared with linear cables. For irregular waves the power spectral densities (PSD‟s) has been computed for sway and heave degrees of freedom, at 45 0 wave direction PSD‟s are higher with linear cables as compared with nonlinear cables and at 90 0 wave direction the PSD‟s are higher with non-linear cables. The mooring force responses are also computed in y and z directions for linear and nonlinear cables.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"9 1","pages":"219-240"},"PeriodicalIF":0.9,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66503302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1