Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology最新文献

{"title":"The Analysis of the Joint Limitation Condition of Wave Height-Period on the Floating Crane Lifting Operation","authors":"Xue-gang Wang, Zong-quan Ying, Ze Chen","doi":"10.1115/omae2019-96461","DOIUrl":"https://doi.org/10.1115/omae2019-96461","url":null,"abstract":"\u0000 Considering the influence of wave period on the motion of ship, the hydrodynamic model of the floating crane-lifting objects coupling system is built. This model can calculate the motion response of floating crane and lifting object under wave conditions with different wave heights and periods. And it takes stability and sea-keeping of ship, personnel comfort as well as safety of equipment into full account. By comparing swing amplitude and acceleration amplitude of the floating crane and the lifting object, the limit working condition including both wave height and period for hoisting operation of the floating crane is determined. The method for limitation operation condition analysis of the floating crane not only offers calculating foundation for the construction operating adaptability of the engineering ship and the allowable working time window of the construction sea area, but also provides a new technical approach to the arrangement for the construction plan.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","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":"128798647","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}

{"title":"Effect of Coal Loading Conditions on Structural Characteristics of LFTS","authors":"H. Eto, K. Iizuka, Ryo Nishigochi, T. Ikoma, Y. Aida, K. Masuda","doi":"10.1115/omae2019-96482","DOIUrl":"https://doi.org/10.1115/omae2019-96482","url":null,"abstract":"\u0000 Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, Large-Scale Floating Coal Transshipment Station (LFTS) was proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. LFTS can store coal equivalent to five times the capacity of one bulk carrier (total 500,000T), and can accommodate 2 bulk carriers at the same time during offloading. The scale of LFTS is 590m × 160m. The LFTS has a flat spread and the elastic behavior becomes the dominant Structure. The upper part of the LFTS is different rigidity partly because the partition wall to be loaded by dividing the coal into each quality is provided. Loaded coal not only changes the draft of the LFTS but also greatly deforms the LFTS and is expected to cause local stress concentration on the structural members. Therefore, this paper investigates wave response characteristics and stress characteristics with the coal loading of the LFTS, and then evaluation of structural strength by limit state design method.\u0000 In this study, linear potential theory and the finite element method (FEM) were used to analyze the static hydroelastic motion under various coal loading condition and wave response of LFTS. And, to grasp the local stress concentration occurring inside the LFTS by using the response results, a detailed model modeling a complicated internal structure was prepared. Zooming analysis which is a method of giving the deformation result by the whole model of LFTS as forced displacement to the local detailed model was carried out. As a result, depending on the coal loading condition and wave conditions, it became clear that LFTS will be in a tough situation.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"40 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113987367","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}

{"title":"Response Characteristics of a Floating Structure With Moon Pools Installed With Vertical Axis Wind Turbines","authors":"Mitsuru Nakamura, T. Ikoma, H. Eto, Y. Aida, K. Masuda","doi":"10.1115/omae2019-96045","DOIUrl":"https://doi.org/10.1115/omae2019-96045","url":null,"abstract":"\u0000 This paper describes characteristics of motion responses and tether tensions of a floating structure with four moon pools, on which one or two vertical axis wind turbines are installed.\u0000 In this study, the authors proposed a twin-VAWT installed floating system, which was a pontoon based structure. However four moon pools were set on. The study conducted model experiments in a wave tank using regular waves with 0.6 to 2.0 seconds in wave periods and 0.02 and 0.04 m in wave height. The model had four moon pools and was installed with one or two vertical axis turbine models. From it, gyroscopic moment effects were investigated. Besides, the study performed numerical calculations with the linear potential theory based method which were a Green function method.\u0000 As a results, responses of the twin-turbine model are not affected by gyroscopic moment. The study discusses motion responses and tether tensions with nonlinear behaviours from mainly the experimental results.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","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":"127694022","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}

{"title":"Development of 3-Dimensional Fully Nonlinear Potential Flow Planar Wave Tank in Framework of OpenFOAM","authors":"Zaibin Lin, L. Qian, W. Bai, Zhihua Ma, Hao Chen, Jian-Guo Zhou","doi":"10.1115/omae2019-96098","DOIUrl":"https://doi.org/10.1115/omae2019-96098","url":null,"abstract":"\u0000 A 3-Dimensional numerical wave tank based on the fully nonlinear potential flow theory has been developed in OpenFOAM, where the Laplace equation of velocity potential is discretized by Finite Volume Method. The water surface is tracked by the semi-Eulerian-Lagrangian method, where water particles on the free surface are allowed to move vertically only. The incident wave is generated by specifying velocity profiles at inlet boundary with a ramp function at the beginning of simulation to prevent initial transient disturbance. Additionally, an artificial damping zone is located at the end of wave tank to sufficiently absorb the outgoing waves before reaching downstream boundary. A five-point smoothing technique is applied at the free surface to eliminate the saw-tooth instability. The proposed wave model is validated against theoretical results and experimental data. The developed solver could be coupled with multiphase Navier-Stokes solvers in OpenFOAM in the future to establish an integrated versatile numerical wave tank for studying efficiently wave structure interaction problems.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"19 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":"130424221","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}

{"title":"Second Order Wave Propagating Along VLFS","authors":"K. Iijima, Chong Ma","doi":"10.1115/omae2019-95132","DOIUrl":"https://doi.org/10.1115/omae2019-95132","url":null,"abstract":"\u0000 This paper addresses the nonlinear deflection wave which propagates along a Very Large Floating Structure (VLFS). The whole VLFS is modeled as a one-dimensional beam afloat on the water surface in a vertical two-dimensional plane. It is assumed that the deflection of the wave propagating along the VLFS has a finite amplitude. The nonlinear wave propagating along the VLFS is investigated by extending the propagation theory of the linear wave along the VLFS. The kinetic and kinematic conditions at the boundary surface between the water and VLFS are considered rigorously up to the 2nd order. The 2nd order wave is obtained as a wave associated with the 1st order wave. The characteristics of the nonlinear wave along the VLFS are elucidated by the mathematical solution. The nonlinear wave along the VLFS has characteristics slightly different from the nonlinear free surface wave, known as Stokes wave. The positive peak of the wave along the VLFS is higher than the negative peak due to the nonlinearity in some frequency range while it is the opposite in the other frequency range. The amplitude of the 2nd order wave increases divergently at the frequency range between the two frequency regimes.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"931 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":"133350092","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}

{"title":"Force Measurements and Stationarity Analysis on the Flow Around a Single Square Column With Rounded Edges","authors":"Dennis M. Gambarine, A. Koop, G. Assi, F. Rampazzo, Rodolfo T. Gonçalves","doi":"10.1115/omae2019-95353","DOIUrl":"https://doi.org/10.1115/omae2019-95353","url":null,"abstract":"\u0000 Studies about the flow around single column are the preliminary way to understand the behaviour of multi-column systems, e.g. semi-submersible platforms and floating offshore wind turbines. The presence of a rounded edge in a square column can include advantages in the constructive phases, on the other hand, can include difficulty in understanding the hydrodynamic behaviour. With this aim this paper presents a 2dof force measurement for a fixed single square column with and without rounded edges. The columns tested have the aspect ratio (H/L) equal to 1.5 representing the typical column height for multi-column platforms. The aim is to investigate the forces between a single square column with rounded edges and sharp edges in different flow incidence. For both edges a total of seven different current incidence angles were performed; 0, 7.5, 15, 22.5, 30, 37.5 and 45. Reynolds number used for the experiment is equal to 40,000. Additional tests were performed to evaluate a quantitative analysis of the uncertainties due to the repeatability and time length of the experiments. This procedure is necessary for the VV studies of CFD codes, and due to this, the database can be utilized for benchmarking.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"42 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":"116923300","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}

{"title":"CFD Simulations of Breaking Stokes Waves","authors":"T. Hino, Harushi Ikenoue, Y. Takagi","doi":"10.1115/omae2019-95946","DOIUrl":"https://doi.org/10.1115/omae2019-95946","url":null,"abstract":"\u0000 Free surface flow simulations using CFD (Computational Fluid Dynamics) can be categorized into two approaches in terms of free surface modeling. One is a two-phase flow model which solves both water and air. The other is a single-phase approach in which only the water region is solved with free surface boundary conditions. Breaking waves have been simulated by many researchers using CFD techniques with two-phase flow models in the most cases. In ship flow CFD applications, however, a single-phase approach is often used since this is considered to be more effective and efficient. However, when a single-phase method is applied to flows with bow wave breaking of a blunt ship, it is observed in some cases that numerical solutions fail to reproduce wave breaking well. This may be due to the differences of the air-water interface treatment between two-phase and single-phase approaches. To investigate these differences, breaking of Stokes waves is simulated by using both single-phase and two-phase flow models. The comparisons of single-phase and two-phase approaches are made in wave profiles, pressure and vorticity distributions. The velocity distributions near the free surface boundaries are also compared. Through these comparisons, impact of free surface boundary conditions in a single-phase approach to wave breaking phenomena is discussed.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"5 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":"124594473","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}

{"title":"Time Domain Simulations of Ship Maneuvering and Roll Motion in Regular Waves Based on a Hybrid Method","authors":"Chengqian Ma, N. Ma, X. Gu","doi":"10.1115/omae2019-95562","DOIUrl":"https://doi.org/10.1115/omae2019-95562","url":null,"abstract":"\u0000 Ship maneuvering performance and rolling in waves under complicated environmental conditions are of significant importance for safety and economic reasons. The existing methods for predicting the maneuvering in adverse sea conditions can be categorized into unified two-time scale model, hybrid approach and CFD method. However, traditional potential methods rely tightly on ship viscous force data from test results, and CFD methods of free running ship require large computational resources consumption. In this paper, a 4-DOF (surge, sway, yaw and roll) model based on MMG method considering the wave effect is established to predict the trajectory and rolling motion with better time efficiency.\u0000 The 1st order wave force and mean 2nd order drift force in this time-domain model are calculated by the 3D panel method and Cummins impose response function. Instead of model experiments, the hydrodynamic derivatives in the maneuvering model can be calculated by RANS-based numerical simulations of the Planar Motion Mechanism (PMM) test in calm water. Verification for grid convergence is also conducted according to state-of-the-art study. The predicted turning trajectory and rolling angle of the S175 containership in regular waves using CFD results show better agreement with experiment data than empirical formula results. Furthermore, it has been demonstrated that this model is also capable of predicting the ship motion in regular waves with practical accuracy. And the effects of the wave frequency, wave height are investigated consequently base on numerical simulation results.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"2 9 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":"133072903","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}

{"title":"Solving 2-D Slamming Problems by the Higher-Order MPS Method With an Improved Pressure Gradient Model","authors":"Ruosi Zha, H. Peng, W. Qiu","doi":"10.1115/omae2019-96775","DOIUrl":"https://doi.org/10.1115/omae2019-96775","url":null,"abstract":"\u0000 A higher-order moving particle semi-implicit (MPS) method was developed to solve water entry problems. The Wendland kernel function was applied in the particle interaction model. Various models for pressure gradient were investigated. To overcome the inconsistency in the original MPS methods, a pressure gradient correction was implemented to guarantee the first-order consistency of gradient. The corrective matrix was modified by using the derivative of the kernel function. A particle shifting technique was also applied to improve the numerical stability. Validation studies were carried out for water entry of a rigid wedge with the tilting angles of 0°, 10° and 20°, and a rigid ship section. The solutions by the present method are generally in good agreement with experimental data and other published numerical results.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"5 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":"128282963","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}

{"title":"Data Assimilation of the Stereo Reconstructed Wave Fields to a Nonlinear Phase Resolved Wave Model","authors":"Shogo Watanabe, W. Fujimoto, T. Nose, T. Kodaira, Graham Davies, D. Lechner, T. Waseda","doi":"10.1115/omae2019-95949","DOIUrl":"https://doi.org/10.1115/omae2019-95949","url":null,"abstract":"\u0000 A stereo camera system was installed facing Southeast at the observational tower owned by the University of Tokyo in the Sagami Bay, Japan. The three-dimensional wave fields were reconstructed from the stereo images, which were successfully captured from April 2017 until now, by using an open source software WASS (Waves Acquisition Stereo System). The significant wave heights and periods calculated from the stereo images covering an area of 80 m by 80 m were compared against those derived from the ultra-sonic wave gauge at the tower. Overall, a reasonable agreement is achieved, but the accuracy of the stereo reconstruction degrades with the distance from the camera. Also, the significant wave period derived from stereo imaging tends to be shorter, likely related to the error at high frequencies. The reconstructed wave field will be assimilated into a phase-resolved nonlinear wave model. The ensemble Higher Order Spectral simulations and the implementation of the a4DVAR data assimilation scheme, allowed us to substantially extend the estimated wave field beyond the stereo imaging domain. A field campaign with an ADCP in the field of view of the stereo camera and two surface wave buoys outside of the view were conducted for validation.","PeriodicalId":120800,"journal":{"name":"Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology","volume":"5 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":"116941351","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}