As the exploration of oceans for oil and gas goes to deeper depths, understanding the riser dynamics is fast becoming a key aspect of such systems’ design. The hydrodynamic loads acting on marine risers such as inertial and drag forces due to the relative motions between the riser and fluid, is of great concern for researchers and exploration systems’ designers. The lack of information regarding some conditions applied on risers systems nowadays, led to an experimental approach to understand the hydrodynamic loads on these conditions, to extract those information, and complement the available literature on this subject. This study provides new insights into the inertial and drag hydrodynamic coefficients (Cm and Cd respectively), how they evolve for higher KCs. These findings should make an important contribution expanding the understanding of the hydrodynamic loads on a circular cylinder. This paper first gives a brief overview of the recent research history of this subject and the theoretical background used, followed by the description of test setup and analysis method. Lastly, the results are presented and discussed in comparison with literature data.
{"title":"Experimental Evaluation of Hydrodynamic Loads on Marine Risers","authors":"V. Vileti, P. Esperança, M. Vitola, M. Vignoles","doi":"10.1115/omae2019-96569","DOIUrl":"https://doi.org/10.1115/omae2019-96569","url":null,"abstract":"\u0000 As the exploration of oceans for oil and gas goes to deeper depths, understanding the riser dynamics is fast becoming a key aspect of such systems’ design. The hydrodynamic loads acting on marine risers such as inertial and drag forces due to the relative motions between the riser and fluid, is of great concern for researchers and exploration systems’ designers.\u0000 The lack of information regarding some conditions applied on risers systems nowadays, led to an experimental approach to understand the hydrodynamic loads on these conditions, to extract those information, and complement the available literature on this subject.\u0000 This study provides new insights into the inertial and drag hydrodynamic coefficients (Cm and Cd respectively), how they evolve for higher KCs. These findings should make an important contribution expanding the understanding of the hydrodynamic loads on a circular cylinder.\u0000 This paper first gives a brief overview of the recent research history of this subject and the theoretical background used, followed by the description of test setup and analysis method. Lastly, the results are presented and discussed in comparison with literature data.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124226159","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}
Manufacture of coatings to tackle the biofouling menace has been of prime concern for the shipping industry since industrial revolution. Even though many types of coatings exist in the market, they have not been able to wipe out the problem of biofouling completely. The proposed approach which combines both the resistance due to biofouling on ships, as well as biofouling characterization, will surely serve as a critical input for the manufacture of efficient anti-fouling coatings. Resistance simulations have been carried out for a tanker ship by Maxsurf® wherein the hull fouling effect has been accounted for by modified ITTC 1978 empirical formula considering roughness. Different draft conditions were relied upon to find out the resistance at various Froude numbers. The fouling growth conditions considered are small and medium calcareous fouling. The simulated results also have been validated by towing tank experiments, for no-foul condition, for speeds varying from 0.3 to 1.1 m/s and different drafts. The additional power requirement was determined for various loading conditions and speed ranges.
{"title":"Biofouling Characterization and its Effect on Resistance of Surface Ship","authors":"Della Thomas, S. Surendran, N. Vasa","doi":"10.1115/omae2019-96220","DOIUrl":"https://doi.org/10.1115/omae2019-96220","url":null,"abstract":"\u0000 Manufacture of coatings to tackle the biofouling menace has been of prime concern for the shipping industry since industrial revolution. Even though many types of coatings exist in the market, they have not been able to wipe out the problem of biofouling completely. The proposed approach which combines both the resistance due to biofouling on ships, as well as biofouling characterization, will surely serve as a critical input for the manufacture of efficient anti-fouling coatings. Resistance simulations have been carried out for a tanker ship by Maxsurf® wherein the hull fouling effect has been accounted for by modified ITTC 1978 empirical formula considering roughness. Different draft conditions were relied upon to find out the resistance at various Froude numbers. The fouling growth conditions considered are small and medium calcareous fouling. The simulated results also have been validated by towing tank experiments, for no-foul condition, for speeds varying from 0.3 to 1.1 m/s and different drafts. The additional power requirement was determined for various loading conditions and speed ranges.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114189762","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}
Estimating added resistance and motions of a ship in waves are essential to predict fuel consumption and speed loss. The added resistance and motions of the 3600 TEU KRISO container ship (KCS) in regular head waves under different wavelengths are investigated using Reynolds-Averaged Navier-Stokes (RANS) method. Volume of Fluid (VOF) method is applied to capture the free surface. The in-house computational fluid dynamics solver, naoe-FOAM-SJTU, is used to compute the added resistance and motions of KCS in regular head waves. Firstly, the first-order Stokes waves in deep water are adopted and generated in naoe-FOAM-SJTU as a numerical wave tank. Secondly, it is presented that the KCS with a Froude number of 0.261 advances in these waves. Regular wave conditions with a wide range of wavelength (0.65 < λ/L < 1.95) are considered. The variations of resistance, pitch and heave show good agreement with experimental results. To investigate nonlinear behaviors of predicted results, Fast Fourier Transform (FFT) is applied to analyze the results of resistance, heave and pitch with in head wave (μ = 180°). KCS with and without motions is also compared to investigate the relationship between components of resistance and wavelengths. The results of added resistances show that the added resistance of KCS is mainly induced by ship diffraction in short waves. The wave diffraction is not affected by wave frequency. In addition, CFD can accurately calculate the problem on added resistance and ship motions.
估算船舶在波浪中的附加阻力和运动对于预测燃油消耗和航速损失至关重要。采用reynolds - average Navier-Stokes (RANS)方法研究了3600teu的KRISO集装箱船(KCS)在不同波长的规则头波中的附加阻力和运动。采用流体体积法(VOF)捕获自由表面。使用内部计算流体动力学求解器naoe-FOAM-SJTU计算了KCS在规则头波中的附加阻力和运动。首先，采用naoe-FOAM-SJTU作为数值波槽，在深水中生成一阶Stokes波;其次，提出了弗劳德数为0.261的KCS在这些波中前进。考虑了具有宽波长范围(0.65 < λ/L < 1.95)的规则波条件。阻力、俯仰和升沉的变化与实验结果吻合较好。为了研究预测结果的非线性行为，采用快速傅里叶变换(FFT)对头波为180°时的阻力、垂荡和俯仰结果进行了分析。还比较了有运动和无运动的KCS，研究了电阻和波长分量之间的关系。附加电阻的结果表明，KCS的附加电阻主要是由船舶在短波中的衍射引起的。波的衍射不受波频的影响。此外，CFD可以准确计算附加阻力和船舶运动问题。
{"title":"Study of Wave Added Resistance and Motions of KCS in Waves With Different Wave Lengths","authors":"Hao Guo, D. Wan","doi":"10.1115/omae2019-95526","DOIUrl":"https://doi.org/10.1115/omae2019-95526","url":null,"abstract":"\u0000 Estimating added resistance and motions of a ship in waves are essential to predict fuel consumption and speed loss. The added resistance and motions of the 3600 TEU KRISO container ship (KCS) in regular head waves under different wavelengths are investigated using Reynolds-Averaged Navier-Stokes (RANS) method. Volume of Fluid (VOF) method is applied to capture the free surface. The in-house computational fluid dynamics solver, naoe-FOAM-SJTU, is used to compute the added resistance and motions of KCS in regular head waves. Firstly, the first-order Stokes waves in deep water are adopted and generated in naoe-FOAM-SJTU as a numerical wave tank. Secondly, it is presented that the KCS with a Froude number of 0.261 advances in these waves. Regular wave conditions with a wide range of wavelength (0.65 < λ/L < 1.95) are considered. The variations of resistance, pitch and heave show good agreement with experimental results.\u0000 To investigate nonlinear behaviors of predicted results, Fast Fourier Transform (FFT) is applied to analyze the results of resistance, heave and pitch with in head wave (μ = 180°). KCS with and without motions is also compared to investigate the relationship between components of resistance and wavelengths. The results of added resistances show that the added resistance of KCS is mainly induced by ship diffraction in short waves. The wave diffraction is not affected by wave frequency. In addition, CFD can accurately calculate the problem on added resistance and ship motions.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"78 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116312817","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}
R. Saito, N. Hashimoto, Takashi Fujiki, K. Kawaguchi, Masao Mitsui
An upgraded submerged Doppler-type directional Wave Meter (DWM) can measure 31 wave quantities related to directional wave motions, i.e., water surface elevation, 3 components of water particle velocities at each layer of 10 different water depths ranging from shallow to deep. In this study, accuracy of directional spectrum estimation is investigated for various cases where directional spectra are estimated with various sets of different number of wave quantities measured with DWM. As a result, accuracy improvement is confirmed in some wave conditions when more quantities are applied to the estimations, compared with the cases where a few wave quantities are applied to the estimations. On the other hand, it was found that when the directional spectra are estimated by adding the water particle velocity components at the deep water depths, the energy concentration of the direction function tends to be estimated higher in proportion to the number of observation layers of the deeper water particle velocity components. Since this feature should be clarified in investigating characteristics of directional spectra observed with DWM, we will continue further investigation for more accurate and reliable directional spectrum estimation.
{"title":"Studies Toward the Development of Accurate Directional Spectrum Estimation Method Using Field Observation Data","authors":"R. Saito, N. Hashimoto, Takashi Fujiki, K. Kawaguchi, Masao Mitsui","doi":"10.2208/KAIGAN.74.I_115","DOIUrl":"https://doi.org/10.2208/KAIGAN.74.I_115","url":null,"abstract":"\u0000 An upgraded submerged Doppler-type directional Wave Meter (DWM) can measure 31 wave quantities related to directional wave motions, i.e., water surface elevation, 3 components of water particle velocities at each layer of 10 different water depths ranging from shallow to deep. In this study, accuracy of directional spectrum estimation is investigated for various cases where directional spectra are estimated with various sets of different number of wave quantities measured with DWM. As a result, accuracy improvement is confirmed in some wave conditions when more quantities are applied to the estimations, compared with the cases where a few wave quantities are applied to the estimations. On the other hand, it was found that when the directional spectra are estimated by adding the water particle velocity components at the deep water depths, the energy concentration of the direction function tends to be estimated higher in proportion to the number of observation layers of the deeper water particle velocity components. Since this feature should be clarified in investigating characteristics of directional spectra observed with DWM, we will continue further investigation for more accurate and reliable directional spectrum estimation.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122063062","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}
A spectrum filtering technique has been introduced to improve harmonic analysis in this study. The impact of site characterization and physical processes have been examined to justify the necessity of applying the spectrum filtering technique following classic harmonic analysis. Investigations show that the imperfection of the harmonic toolbox, e.g. T_Tide, could be attributed to significant contributions to the long period energy of density gradient and background currents, the greater variability of current amplitude energy, and the larger energy surrounding the clustering diurnal and semi-diurnal tidal constituents. From applications on hydrodynamic model data, this study supports the argument that harmonic analysis with the spectrum filtering technique could significantly improve the accuracy of tidal energy and residuals separation.
{"title":"Effective Harmonic Analysis With Spectrum Filtering Technique","authors":"Z. Peng, Hazel Grant, R. Sproson","doi":"10.1115/omae2019-96021","DOIUrl":"https://doi.org/10.1115/omae2019-96021","url":null,"abstract":"\u0000 A spectrum filtering technique has been introduced to improve harmonic analysis in this study. The impact of site characterization and physical processes have been examined to justify the necessity of applying the spectrum filtering technique following classic harmonic analysis. Investigations show that the imperfection of the harmonic toolbox, e.g. T_Tide, could be attributed to significant contributions to the long period energy of density gradient and background currents, the greater variability of current amplitude energy, and the larger energy surrounding the clustering diurnal and semi-diurnal tidal constituents. From applications on hydrodynamic model data, this study supports the argument that harmonic analysis with the spectrum filtering technique could significantly improve the accuracy of tidal energy and residuals separation.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122092768","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}
Tianlong Mei, Y. Liu, M. T. Ruiz, M. Vantorre, E. Lataire, Changyuan Chen, Z. Zou
The ship’s manoeuvring behaviour in waves is significantly different from that in calm water. In this context, the present work uses a hybrid method combining potential flow theory and Computational Fluid Dynamics (CFD) techniques for the prediction of ship manoeuvrability in regular waves. The mean wave-induced drift forces are calculated by adopting a time domain 3D higher-order Rankine panel method, which includes the effect of the lateral speed and forward speed. The hull-related hydrodynamic derivatives are determined based on a RANS solver using the double body flow model. The two-time scale method is applied to integrate the improved seakeeping model in a 3-DOF modular type Manoeuvring Modelling Group (MMG model) to investigate the ship’s manoeuvrability in regular waves. Numerical simulations are carried out to predict the turning circle in regular waves for the S175 container carrier. The turning circle’s main characteristics as well as the wave-induced motions are evaluated. A good agreement is obtained by comparing the numerical results with experimental data obtained from existing literature. This demonstrates that combining potential flow theory with CFD techniques can be used efficiently for predicting the manoeuvring behaviour in waves. This is even more true when the manoeuvring derivatives cannot be obtained from model tests when there is lack of such experimental data.
{"title":"Hybrid Method for Predicting Ship Manoeuvrability in Regular Waves","authors":"Tianlong Mei, Y. Liu, M. T. Ruiz, M. Vantorre, E. Lataire, Changyuan Chen, Z. Zou","doi":"10.1115/omae2019-95249","DOIUrl":"https://doi.org/10.1115/omae2019-95249","url":null,"abstract":"\u0000 The ship’s manoeuvring behaviour in waves is significantly different from that in calm water. In this context, the present work uses a hybrid method combining potential flow theory and Computational Fluid Dynamics (CFD) techniques for the prediction of ship manoeuvrability in regular waves. The mean wave-induced drift forces are calculated by adopting a time domain 3D higher-order Rankine panel method, which includes the effect of the lateral speed and forward speed. The hull-related hydrodynamic derivatives are determined based on a RANS solver using the double body flow model. The two-time scale method is applied to integrate the improved seakeeping model in a 3-DOF modular type Manoeuvring Modelling Group (MMG model) to investigate the ship’s manoeuvrability in regular waves.\u0000 Numerical simulations are carried out to predict the turning circle in regular waves for the S175 container carrier. The turning circle’s main characteristics as well as the wave-induced motions are evaluated. A good agreement is obtained by comparing the numerical results with experimental data obtained from existing literature. This demonstrates that combining potential flow theory with CFD techniques can be used efficiently for predicting the manoeuvring behaviour in waves. This is even more true when the manoeuvring derivatives cannot be obtained from model tests when there is lack of such experimental data.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126792100","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}
High-bandwidth underwater wireless communication can be achieved over long-distance using a swarm of Autonomous Underwater Vehicles (AUVs) relaying an optical signal. The swarm behavior is of critical importance as it will determine the robustness and the autonomy of the communication link. Each vehicle must remain at a distance lower than the optical communication system range from each other while fighting against environmental disturbances such as ocean current. This technology could be a game changer in the deployment and supervision of future oil wells and of deep sea mining which will be deeper and deeper in the oceans. We developed an optimization program to maximize the communication link autonomy while assuring its robustness. The nonlinear optimization problem is transformed to a Second-Order Cone Problem (SOCP), a special case of convex problems that can be efficiently solved with Yalmip on Matlab. We show on two case studies that the autonomy of the swarm and thus the lifetime of the communication link is increased by more than 10% compared to a direct approach where the reference position of the vehicles is fixed.
{"title":"Optimization of a Swarm of Autonomous Underwater Vehicles for High-Bandwidth Underwater Wireless Communication","authors":"A. Immas, Mohammad-Reza Alam","doi":"10.1115/omae2019-96285","DOIUrl":"https://doi.org/10.1115/omae2019-96285","url":null,"abstract":"\u0000 High-bandwidth underwater wireless communication can be achieved over long-distance using a swarm of Autonomous Underwater Vehicles (AUVs) relaying an optical signal. The swarm behavior is of critical importance as it will determine the robustness and the autonomy of the communication link. Each vehicle must remain at a distance lower than the optical communication system range from each other while fighting against environmental disturbances such as ocean current. This technology could be a game changer in the deployment and supervision of future oil wells and of deep sea mining which will be deeper and deeper in the oceans. We developed an optimization program to maximize the communication link autonomy while assuring its robustness. The nonlinear optimization problem is transformed to a Second-Order Cone Problem (SOCP), a special case of convex problems that can be efficiently solved with Yalmip on Matlab. We show on two case studies that the autonomy of the swarm and thus the lifetime of the communication link is increased by more than 10% compared to a direct approach where the reference position of the vehicles is fixed.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126333584","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}
The Regional Ocean Modeling System (ROMS) is a free-surface, terrain-following, primitive equations ocean model and it was implemented to perform a high-resolution 10-year hindcast study of Solomon’s Sea circulation patterns. The model was executed with a resolution of 1/36°, initial conditions from HYCOM+NCODA Global 1/12° and was forced by CFSR/CFSV2 momentum, mass and heat fluxes. The model was validated by comparing the simulated temperatures, salinities and flow patterns with satellite data, Argo floats and Ship ADCP measurements. In general, the model captured the main circulation patterns and performed well for the Solomon Sea. The modelled Temperature and Salinity profiles were comparable with the observations, with some error variability in the thermocline layer, which agreed with previous studies.
区域海洋模拟系统(ROMS)是一个自由表面、地形跟踪、原始方程的海洋模型，它被用于对所罗门海环流模式进行高分辨率的10年后发研究。模型在初始条件为HYCOM+NCODA Global 1/12°的1/36°分辨率下执行，并由CFSR/CFSV2动量、质量和热通量强制执行。通过将模拟温度、盐度和水流模式与卫星数据、Argo浮标和船舶ADCP测量结果进行比较，验证了该模型的有效性。总的来说，该模式捕获了所罗门海的主要环流模式，表现良好。模拟的温度和盐度剖面与观测结果相当，在温跃层中存在一些误差变异，这与以前的研究一致。
{"title":"Evaluation of the Ocean Circulation for the Solomon Sea Using the Regional Ocean Modeling System (ROMS)","authors":"A. Bento, H. Coelho, Chunxue Yang","doi":"10.1115/omae2019-96179","DOIUrl":"https://doi.org/10.1115/omae2019-96179","url":null,"abstract":"\u0000 The Regional Ocean Modeling System (ROMS) is a free-surface, terrain-following, primitive equations ocean model and it was implemented to perform a high-resolution 10-year hindcast study of Solomon’s Sea circulation patterns. The model was executed with a resolution of 1/36°, initial conditions from HYCOM+NCODA Global 1/12° and was forced by CFSR/CFSV2 momentum, mass and heat fluxes. The model was validated by comparing the simulated temperatures, salinities and flow patterns with satellite data, Argo floats and Ship ADCP measurements. In general, the model captured the main circulation patterns and performed well for the Solomon Sea. The modelled Temperature and Salinity profiles were comparable with the observations, with some error variability in the thermocline layer, which agreed with previous studies.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132478678","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}
Changyuan Chen, M. T. Ruiz, E. Lataire, G. Delefortrie, Marc Mansuy, Tianlong Mei, M. Vantorre
In order to identify more accurately and efficiently the unknown parameters of a ship motions model, a novel Nonlinear Least Squares Support Vector Machine (NLSSVM) algorithm, whose penalty factor and Radial Basis Function (RBF) kernel parameters are optimised by the Beetle Antennae Search algorithm (BAS), is proposed and investigated. Aiming at validating the accuracy and applicability of the proposed method, the method is employed to identify the linear and nonlinear parameters of the first-order nonlinear Nomoto model with training samples from numerical simulation and experimental data. Subsequently, the identified parameters are applied in predicting the ship motion. The predicted results illustrate that the new NLSSVM-BAS algorithm can be applied in identifying ship motion’s model, and the effectiveness is verified. Compared among traditional identification approaches with the proposed method, the results display that the accuracy is improved. Moreover, the robust and stability of the NLSSVM-BAS are verified by adding noise in the training sample data.
{"title":"Ship Manoeuvring Model Parameter Identification Using Intelligent Machine Learning Method and the Beetle Antennae Search Algorithm","authors":"Changyuan Chen, M. T. Ruiz, E. Lataire, G. Delefortrie, Marc Mansuy, Tianlong Mei, M. Vantorre","doi":"10.1115/omae2019-95565","DOIUrl":"https://doi.org/10.1115/omae2019-95565","url":null,"abstract":"\u0000 In order to identify more accurately and efficiently the unknown parameters of a ship motions model, a novel Nonlinear Least Squares Support Vector Machine (NLSSVM) algorithm, whose penalty factor and Radial Basis Function (RBF) kernel parameters are optimised by the Beetle Antennae Search algorithm (BAS), is proposed and investigated. Aiming at validating the accuracy and applicability of the proposed method, the method is employed to identify the linear and nonlinear parameters of the first-order nonlinear Nomoto model with training samples from numerical simulation and experimental data. Subsequently, the identified parameters are applied in predicting the ship motion. The predicted results illustrate that the new NLSSVM-BAS algorithm can be applied in identifying ship motion’s model, and the effectiveness is verified. Compared among traditional identification approaches with the proposed method, the results display that the accuracy is improved. Moreover, the robust and stability of the NLSSVM-BAS are verified by adding noise in the training sample data.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130977536","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}
In order to study the super large container ship characteristics of the wind resistance coefficient and the air flow field in the different angle of attack, wind tunnel test based on the 14000 containers ship is carried out on the state of the design draft. The wind resistance coefficient of superstructure is obtained through test. The CFD (Computational Fluid Dynamics) technology is introduced to simulate the wind resistance and yaw moment of the model. The numerical results are basically in agreement with the experimental data. The results indicates that with the increase of the wind direction angle, the longitudinal wind resistance coefficient curve shows a “sine curve” rule and exists opposite resistance extremums, whereas the lateral wind resistance coefficient curve presents a parabolic change rule. Numerical simulation method is proved has high accuracy for wind resistance prediction of container ship. The size of wind load on the ship is related to the form and size of the wake region.
{"title":"Research of Wind Resistance and Flow Field of Container Ship","authors":"Sun Zhiyuan, Li Ping, Hanbing Sun","doi":"10.1115/omae2019-96798","DOIUrl":"https://doi.org/10.1115/omae2019-96798","url":null,"abstract":"\u0000 In order to study the super large container ship characteristics of the wind resistance coefficient and the air flow field in the different angle of attack, wind tunnel test based on the 14000 containers ship is carried out on the state of the design draft. The wind resistance coefficient of superstructure is obtained through test. The CFD (Computational Fluid Dynamics) technology is introduced to simulate the wind resistance and yaw moment of the model. The numerical results are basically in agreement with the experimental data. The results indicates that with the increase of the wind direction angle, the longitudinal wind resistance coefficient curve shows a “sine curve” rule and exists opposite resistance extremums, whereas the lateral wind resistance coefficient curve presents a parabolic change rule. Numerical simulation method is proved has high accuracy for wind resistance prediction of container ship. The size of wind load on the ship is related to the form and size of the wake region.","PeriodicalId":124589,"journal":{"name":"Volume 7B: Ocean Engineering","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133955600","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：