Ocean Systems Engineering-An International Journal最新文献

Performance evaluation of a seawater exchange breakwater with Helmholtz resonator using OpenFOAM 基于OpenFOAM的亥姆霍兹谐振腔海水交换防波堤性能评价

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Ocean Systems Engineering-An International Journal Pub Date : 2021-09-01 DOI: 10.12989/OSE.2021.11.3.217

Arun George, I. Cho

{"title":"Performance evaluation of a seawater exchange breakwater with Helmholtz resonator using OpenFOAM","authors":"Arun George, I. Cho","doi":"10.12989/OSE.2021.11.3.217","DOIUrl":"https://doi.org/10.12989/OSE.2021.11.3.217","url":null,"abstract":"In this study, the three dimensional numerical simulation of a seawater exchange breakwater using the Helmholtz resonator has been carried out in OpenFOAM. When the frequency of the incident wave coincides with one of the natural frequencies of a closed semi-circular resonator, resonance occurs in the resonator. The amplified water elevation in a resonator pushes the seawater periodically into the ocean/port side through the water channel and consequently improves the water quality of the port. The numerical model is based on Reynolds Averaged Navier Stokes equations with SST turbulence model. The VOF (Volume of Fluid) method is used to capture the free surface behavior. The numerical model is validated with model experiments conducted by Cho (2001) in a two-dimensional wave tank for regular waves. Numerical simulations for the prototype model in irregular waves based on the JONSWAP spectrum are also conducted to show whether the proposed seawater exchange breakwater can be feasible to the real seas. It is found that the seawater exchanging rate is greatly enhanced in the low-frequency wave region where the frequency of the Helmholtz resonance situates. If designing the Helmholtz resonator properly, it can supply the clean seawater sustainedly into the port side without additional electric power.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"11 1","pages":"217"},"PeriodicalIF":0.9,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42136334","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

Wheel over point mathematical model 车轮过点数学模型

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Ocean Systems Engineering-An International Journal Pub Date : 2021-09-01 DOI: 10.12989/OSE.2021.11.3.203

Amir Syawal Kamis, A. Fuad, A. Ashaari, C. Noor

引用次数: 3

A time-domain method for analyzing the ship roll stabilization based on active fin control 基于主动鳍控制的船舶横摇镇定时域分析方法

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Ocean Systems Engineering-An International Journal Pub Date : 2021-09-01 DOI: 10.12989/OSE.2021.11.3.275

N. Patil, S. Rajendran

{"title":"A time-domain method for analyzing the ship roll stabilization based on active fin control","authors":"N. Patil, S. Rajendran","doi":"10.12989/OSE.2021.11.3.275","DOIUrl":"https://doi.org/10.12989/OSE.2021.11.3.275","url":null,"abstract":"The present work focuses on the development of a numerical body nonlinear time-domain method for estimating the effect of active roll fin stabilizers on ship roll motion in both regular and irregular seaway. The time-domain analysis aims at providing fast and accurate ship responses that will be useful during the design process through accurate estimation of the environmental loads. A strip theory-based approach is followed where the Froude-Krylov and hydrostatic forces are calculated for the exact wetted surface area for every time step. The equations of motions are formulated in the body frame and consider the six degrees of coupled motions. The active fin, rudder, and propeller modules are included in the simulation. This leads to accurate modeling of the system dynamics. The numerical unstabilized roll motion is validated with experimental seakeeping simulations conducted on a Coastal Research Vessel (CRV). The phenomena of Parametric Rolling (PR) is identified during the numerical investigation of the candidate vessel. Besides, a nonlinear PID (NPID) control technique and LQR method is implemented for active roll motion control and its performance is observed in regular as well as irregular waves. The proposed numerical approach proves to be an effective and realistic method in evaluating the 6-DoF coupled ship motion responses.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"13 11","pages":"275"},"PeriodicalIF":0.9,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41311529","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

Assessment of global wave forces and moments on porous vertical barriers in random wave fields 随机波场中多孔垂直屏障的整体波浪力和力矩的评估

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Ocean Systems Engineering-An International Journal Pub Date : 2021-09-01 DOI: 10.12989/OSE.2021.11.3.237

S. Neelamani, N. Al-Anjari

引用次数: 0

Study of added resistance and seakeeping of KVLCC2 in waves with and without propeller KVLCC2在有螺旋桨和无螺旋桨波浪中的附加阻力和耐波性研究

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Ocean Systems Engineering-An International Journal Pub Date : 2021-06-01 DOI: 10.12989/OSE.2021.11.2.123

Hassiba Ouargli, B. Hamoudi

{"title":"Study of added resistance and seakeeping of KVLCC2 in waves with and without propeller","authors":"Hassiba Ouargli, B. Hamoudi","doi":"10.12989/OSE.2021.11.2.123","DOIUrl":"https://doi.org/10.12989/OSE.2021.11.2.123","url":null,"abstract":"Numerical simulation of a full-scale ship model, KVLCC2, has been conducted applying the Reynolds Averaged Navier-Stokes (RANS) approach using the STARCCM+ commercial computational fluid dynamics (CFD) software to calculate total resistance, seakeeping and Pitch Moments. Results are obtained for the speed of 15.5 Knots under different sea conditions (calm water, regular waves and irregular waves), The total resistance calculated for the KVLCC2 ship hull in calm water is in a good agreement with the results from experiments and the results for motion (heave and pitch) and added resistance in waves were compared to numerical and experimental findings from previous research with good agreement. In addition to wave excitations, the full-scale ship model was subjected to propeller excitations using the virtual disk model from the CFD software. The body force propeller method, which simplified the full propeller characteristic of the KVLCC2 into a resultant body force, is applied to the virtual disk model. Results are compared with results from the hull-only model. A comparison of the wake results with previous work is also presented.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"11 1","pages":"123"},"PeriodicalIF":0.9,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45937284","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: 0

A comparison of smoothed particle hydrodynamics simulation with exact results from a nonlinear water wave model 光滑颗粒流体力学模拟与非线性水波模型精确结果的比较

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Ocean Systems Engineering-An International Journal Pub Date : 2021-06-01 DOI: 10.12989/OSE.2021.11.2.185

H. X. Nguyen, V. Dinh, B. Basu

引用次数: 1

Fish-ridge wind turbine aerodynamics characteristics in Oscillating Water Column (OWC) system 振荡水柱(OWC)系统鱼脊式风力机的空气动力学特性

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Ocean Systems Engineering-An International Journal Pub Date : 2021-06-01 DOI: 10.12989/OSE.2021.11.2.141

N. Hiron, I. Giriantari, L. Jasa, I. Kumara

{"title":"Fish-ridge wind turbine aerodynamics characteristics in Oscillating Water Column (OWC) system","authors":"N. Hiron, I. Giriantari, L. Jasa, I. Kumara","doi":"10.12989/OSE.2021.11.2.141","DOIUrl":"https://doi.org/10.12989/OSE.2021.11.2.141","url":null,"abstract":"This paper analyzes the fish-ridge type wind turbine performance and characteristics of energy extraction applied in a low wave Oscillating Water Column (OWC) system. This article contributes to providing a better understanding of the application of OWC and VAWT in a low wave environment. The aerodynamic characteristics of the three-blade fish-ridge turbine in an OWC chamber have been successfully investigated. CFD simulation with Reynolds-Averaged-Stokes (RANS) equations was used to obtain airspeed and air pressure contours under compressed and decompressed conditions in the turbine blades. Experiments on laboratory scale test rig also obtained data. The blade torque and turbine power coefficient at different AoA were validated through the experimental test to obtain numerical equations for the relationship between airspeeds, torque, tip speed ratio, and turbine power. The turbine design was 0.2 m long and 0.1 m wide and with an overlap ratio of 15%. The maximum tested airspeed was 20m/s. We found that the fish-ridge turbine has a homogeneous air velocity distribution and pressure due to the 15% overlap area. The maximum efficiency of the fish-ridge turbine under compressed conditions was 30% at TSR 0.9, while under decompressed conditions, the maximum efficiency reached 28% at TSR 0.6.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"11 1","pages":"141"},"PeriodicalIF":0.9,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46925253","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

Optimum design of miniature platforms for marginal fields 边际油田微型平台的优化设计

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Ocean Systems Engineering-An International Journal Pub Date : 2021-06-01 DOI: 10.12989/OSE.2021.11.2.099

Shan Miao, Yuming Liu, D. Yue

引用次数: 0

Prediction of scour around single vertical piers with different cross-section shapes 不同截面形状单墩冲刷预测

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Ocean Systems Engineering-An International Journal Pub Date : 2021-03-01 DOI: 10.12989/OSE.2021.11.1.043

Amir Bordbar, S. Sharifi, H. Hemida

{"title":"Prediction of scour around single vertical piers with different cross-section shapes","authors":"Amir Bordbar, S. Sharifi, H. Hemida","doi":"10.12989/OSE.2021.11.1.043","DOIUrl":"https://doi.org/10.12989/OSE.2021.11.1.043","url":null,"abstract":"In the present work, a 3D numerical model is proposed to study local scouring around single vertical piers with different cross-section shapes under steady-current flow. The model solves the flow field and sediment transport processes using a coupled approach. The flow field is obtained by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations in combination with the k-w SST turbulence closure model and the sediment transport is considered using both bedload and suspended load models. The proposed model is validated against the empirical measurements of local scour around single vertical piers with circular, square, and diamond cross-section shapes obtained from the literature. The measurement of scour depth in equilibrium condition for the simulations reveal the differences of 4.6%, 6.7% and 13.1% from the experimental measurements for the circular, square, and diamond pier cases, respectively. The model displayed a remarkable performance in the prediction of scour around circular and square piers where horseshoe vortices (HSVs) have a leading impact on scour progression. On the other hand, the maximum deviation was found in the case of the diamond pier where HSVs are weak and have minimum impact on the formation of local scour. Overall, the results confirm that the prediction capability of the present model is almost independent of the strength of the formed HSVs and pier cross-section shapes.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"11 1","pages":"43"},"PeriodicalIF":0.9,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49664413","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

Aerodynamic behaviour of double hinged articulated loading platforms 双铰铰接装载平台的气动特性

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Ocean Systems Engineering-An International Journal Pub Date : 2021-03-01 DOI: 10.12989/OSE.2021.11.1.017

M. M. Zaheer, S. D. Hasan, Nazrul Islam, M. Aslam

{"title":"Aerodynamic behaviour of double hinged articulated loading platforms","authors":"M. M. Zaheer, S. D. Hasan, Nazrul Islam, M. Aslam","doi":"10.12989/OSE.2021.11.1.017","DOIUrl":"https://doi.org/10.12989/OSE.2021.11.1.017","url":null,"abstract":"Articulated loading platforms (ALPs) belongs to a class of offshore structures known as compliant. ALP motions have time periods falling in the wind excitation frequency range due to their compliant behaviour. This paper deals with the dynamic behavior of a double hinged ALP subjected to low-frequency wind forces with random waves. Nonlinear effects due to variable submergence, fluctuating buoyancy, variable added mass, and hydrodynamic forces are considered in the analysis. The random sea state is characterized by the Pierson-Moskowitz (P-M) spectrum. The wave forces on the submerged elements of the platform's shaft are calculated using Morison's Equation with Airy's linear wave theory ignoring diffraction effects. The fluctuating wind load has been estimated using Ochi and Shin wind velocity spectrum for offshore structures. The nonlinear dynamic equation of motion is solved in the time domain by the Wilson-e method. The wind-structure interactions, along with the effect of various other parameters on the platform response, are investigated. The effect of offset of aerodynamic center (A.C.) with the center of gravity (C.G.) of platform superstructure has also been investigated. The outcome of the analyses indicates that low-frequency wind forces affect the response of ALP to a large extent, which otherwise is not enhanced in the presence of only waves. The mean wind modifies the mean position of the platform surge response to the positive side, causing an offset. Various power spectral densities (PSDs) under high and moderate sea states show that apart from the significant peak occurring at the two natural frequencies, other prominent peaks also appear at very low frequencies showing the influence of wind on the response.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"11 1","pages":"17"},"PeriodicalIF":0.9,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47856363","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