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Effect of Upward Internal Flow on Dynamics of Riser Model Subject to Shear Current

China Ocean engineering 2012年第1期26卷 95-108页

作者：陈正寿 KIM Wu-joan 熊丛博 School of Naval Architecture and Civil Engineering Zhejiang Ocean University Department of Ocean Engineering Mokpo National University The First Institute of Oceanography State Oceanic Administration

Numerical study about vortex-induced vibration （V/V） related to a flexible riser model in consideration of internal flow progressing inside has been performed. The main objective of this work is to investigate the coupled fluid-structure interaction （FSI） taking place between tensioned riser model, external shear current and upward-progressing internal flow （from ocean bottom to surface）. A CAE technology behind the current research which combines structural software with the CFD technology has been proposed. According to the result from dynamic analysis, it has been found that the existence of upward-progressing internal flow does play an important role in determining the vibration mode （/dominant frequency）, vibration intensity and the magnitude of instantaneous vibration amplitude, when the velocity ratio of internal flow against external current is relatively high. As a rule, the larger the velocity of intemal flow is, the more it contributes to the dynamic vibration response of the flexible riser model. In addition, multi-modal vibration phenomenon has been widely observed, for asymmetric curvature along the riser span emerges in the case of external shear current being imposed.

关键词： internal flow upward-progressing fluid-structure interaction velocity ratio

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Methodology for dynamic analysis of offloading operations

Methodology for dynamic analysis of offloading operations

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2004 IFAC Conference on Computer Applications in Marine Systems, CAMS 2004

作者： Morishita, Helio Mitio Tannuri, Eduardo A. Bravin, Tiago T. Department of Naval Architecture and Oceanic Engineering University of São Paulo Brazil

The relative positioning between the Floating, Production, Storage and Offloading (FPSO) and the shuttle vessel during offloading should be analysed carefully, since the safety of the operation is of primary concern. In order to avoid collision, the shuttle vessel is kept away from the FPSO through the force of a tug-boat or by a dynamic positioning system. In both cases it is convenient to perform a preliminary study of their dynamics in order to obtain a guideline to set the best reference as well as a control approach. This paper presents a methodology for studying the dynamics and control of FPSO and shuttle vessel in tandem configuration systematically, using two software tools. The first tool allows the study of static solutions and the results have shown complex behavior, with a multiplicity of static equilibrium solutions the number and stability properties of which vary according to the combinations of the environmental conditions and vessel parameters. The second tool performs dynamic analysis of the FPSO-shuttle vessel, making it also possible to include a dynamic positioning system. Some results are compared with those obtained experimentally. Copyright © 2004 IFAC.

关键词： Stability

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Motion control system of underwater robot without rudder and wing

Motion control system of underwater robot without rudder and...

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2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2006

作者： Yong, Gan Yushan, Sun Lei, Wan Yongjie, Pang Department of Naval Architecture and Oceanic Engineering Harbin Engineering University Harbin Heilongjiang Province China

ISBN: (纸本)142440259X

Motion control system of underwater robot without rudder and wing is presented with hardware and software architecture. Considering coupling effects and thrust reduction of propellers, the control layer, perception layer and executive layer in underwater robot system architecture are modified. In control layer, a nonlinear controller is presented to handle coupling effects between the longitudinal dimension and other dimensions of underwater robot. The stability of the controller is verified with Lyapunov function. A virtual sonar based guidance law is proposed in perception layer to coordinate motions on different dimensions, which originates from the behavior of human beings. In executive layer a kind of thruster configuration for high speed traveling is introduced to handle thrust reduction of tunnel thrusters. Finally, the reliability and feasibility of the motion control system are demonstrated by sea trial. © 2006 IEEE.

关键词： Robotics

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Two-scale polarimetric emissivity model: Efficiency improvements and comparisons with data

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Progress in Electromagnetics Research 2002年 37卷 205-219页

作者： Lyzenga, D.R. Vesecky, J.F. Department of Naval Architecture and Marine Engineering University of Michigan Ann Arbor MI United States Department of Electrical Engineering University of California Santa Cruz CA United States Atmospheric Oceanic and Space Science Department University of Michigan Ann Arbor MI United States

The two-scale model provides a framework for explaining the polarization and angular dependence of the microwave radiation emitted from the ocean surface. In this model the surface is viewed as a collection of randomly oriented facets. The emissivity of each facet is calculated using the small perturbation method (SPM), and that of the entire surface is obtained by integrating the local emissivity over all possible surface slopes, weighted by the probability of encountering these slopes. Since each SPM calculation involves a double integral, the model requires in principle the evaluation of a fourdimensional integral. This paper explores two methods for reducing the computational time required by the two-scale model. In one version, the azimuthal dependence of the local emissivity is represented by a truncated Fourier series and slope integral is computed numerically. In the second version the slope integral is carried out analytically, after expanding the integrand as a Taylor series in the surface slope. Hydrodynamic modulation effects are included in order to explain the upwind-downwind asymmetry of the emissivity. The calculated emissivities from the two versions of the model are compared with each other and with airborne and spaceborne measurements.

关键词： Perturbation techniques

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Methodology for dynamic analysis of offloading operations

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IFAC Proceedings Volumes 2004年第10期37卷 459-464页

作者： Helio Mitio Morishita Eduardo A. Tannuri Tiago T. Bravin Department of Naval Architecture and Oceanic Engineering of the University of São Paulo

关键词： Offloading Operation Dynamic Positioning System FPSO

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Physical objects on navigation channal simulation models

Physical objects on navigation channal simulation models

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2013 43rd Winter Simulation Conference - Simulation: Making Decisions in a Complex World, WSC 2013

作者： De Oliveira Mota, Daniel Pereira, Newton Narciso Botter, Rui Carlos Medina, Afonso Celso Department of Naval Architecture and Oceanic Engineering Polytechnic School University of Sao Paulo Av. Professor Mello Moraes 2231 Sao Paulo SP 05508-030 Brazil

ISBN: (纸本)9781479939503

This paper presents the results of a simulation using physical objects. This concept integrates the physical dimensions of an entity such as length, width, and weight, with the usual process flow paradigm, recurrent in the discrete event simulation models. Based on a naval logistics system, we applied this technique in an access channel of the largest port of Latin America. This system is composed by vessel movement constrained by the access channel dimensions. Vessel length and width dictates whether it is safe or not to have one or two ships simultaneously. The success delivered by the methodology proposed was an accurate validation of the model, approximately 0.45% of deviation, when compared to real data. Additionally, the model supported the design of new terminals operations for Santos, delivering KPIs such as: canal utilization, queue time, berth utilization, and throughput capability. © 2013 IEEE.

关键词： Discrete event simulation

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Estimation of a moving ship's hulll shape from its wave spectra 12

Estimation of a moving ship's hulll shape from its wave spec...

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12th Annual International Geoscience and Remote Sensing Symposium, IGARSS 1992

作者： Meadows, Guy A. Wu, Zhijian Naval Architecture and Marine Engineering Department University of Michigan Ann ArborMI48109 United States Atmospheric Oceanic and Space Science Department University of Michigan Ann ArborMI48109 United States

ISBN: (纸本)0780301382

This paper presents a technique to estimate a ship's hull shape from its wave spectra based on the relations of the ship's wave spectra, wave amplitude function and hull geometry. The inversion technique is developed through the application of a spectral method together with the constrained linear inversion and maximum likelihood methods. The results from the study show a promising possibility of predicting a moving ship's hull shape through remotely measuring the ship generated wave pattern. © IEEE 1992.

关键词： Hulls (ship)

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Motion Control System architecture of Underwater Robot

Motion Control System Architecture of Underwater Robot

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World Congress on Intelligent Control and Automation (WCICA)

作者： Gan Yong Sun Yushan Wan Lei Pang Yongjie Department of Naval Architecture and Oceanic Engineering Harbin Engineering of Technology Harbin Heilongjiang China

Motion control system architecture of underwater robot is presented, which includes hardware and software architecture. Considering the longitudinal velocity effects on the other dimensions of underwater robot, a nonlinear controller is presented. The stability is verified with Lyapunov function. In order to coordinate motions on different dimensions, a virtual sonar based guidance law is introduced which originates from the behavior of human beings. Finally, the reliability and feasibility of the motion control system are demonstrated by sea trial

关键词： Motion control Robot kinematics Computer architecture Hardware Software architecture Velocity control Robot control Stability Lyapunov method Sonar

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Physical objects on navigation channal simulation models 13

Physical objects on navigation channal simulation models

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Simulation Winter Conference

作者： Daniel de Oliveira Mota Newton Narciso Pereira Rui Carlos Botter Afonso Celso Medina Department of Naval Architecture and Oceanic Engineering Av. Professor Mello Moraes SP BRAZIL

ISBN: (纸本)9781479920778

关键词： Marine vehicles Discrete event simulation Abstracts Security Logistics Statistical analysis Animation

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Functional Assessment of Coastal Buffer Zone Installation Using In-Situ Measurements from Sinji-Myongsasimni Beach

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Journal of Coastal Research 2024年第SP1期116卷 653-657页

作者： Kyong Hwan Kwon Jong Hoon Kim Myeong Ju Hong Il Heum Park Ocean Environment Institute Oceanic C&T Seoul Republic of Korea Department of Naval Architecture and Ocean Engineering Chonnam National University Yeosu Republic of Korea

Kwon, K.H.; Kim, J.H.; Hong, M.J., and Park, I.H., 2023. Functional assessment of coastal buffer zone installation using in-situ measurements from Sinji-Myongsasimni Beach. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 653-657. Charlotte (North Carolina), ISSN *** development around the coast of Sinji-Myongsasimni (SJMS) began in the 1960s, as more communities settled nearby the installation of artificial structures such as breakwaters, stepped seawalls, and jetties were inevitable. However, the increase in such structures has led to a reduction in beach area of the SJMS Beach, resulting in significant coastal erosion. In July 2021, the Wando-Gun County Council, Korea installed a buffer zone in a form of beach nourishment to reduce the acceleration. However, no functionality assessment on buffer zone installation was conducted afterwards. This study aimed to assess the functionality of the buffer zone through the collection of hydrographic and littoral drift data before and after its installation.

关键词： beach nourishment coastal erosion coastal resilience

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