Download or read book Time domain Simulation of Large amplitude Ship Motions Including Capsizing written by Tuanjie Liu and published by . This book was released on 2002 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Time Domain Simulation of Ship Motions and Loads in Large Amplitude Head Waves written by Olgun Guven Hizir and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This PhD thesis presents the development of a practical computational tool named Large Amplitude RESponse (LARes), based on 3D quasi-non-linear time-domain technique, to predict ship motions and loads in large amplitude waves which can be accessible to ship designers. Firstly, a linear 3-D Green source panel code (LARes L1) was developed to perform linear time-domain analysis ship motion and internal load simulations based on the frequency-domain hydrodynamic coefficients which were calculated in the linear PRECAL software. Linear simulations are validated with the linear time-domain PRETTI software results using rectangular barge geometry. The motions, internal loads, global and sectional hydrodynamic forces were agreed well with the linear PRETTI model results in zero and forward speed simulations. Then, non-linear time-domain panel code (LARes L2) was developed in order to predict ship motions and loads in large amplitude waves using the Froude-Krylov nonlinearity level. At each time step, the exact wetted area of the ship surface under the wave profile was calculated and fed in the time-domain motion and load equations while the diffraction and radiation forces were kept as linear. The present program achieved good agreement with the non-linear PRETTI model results both for the barge and S175 container geometries at zero and forward speed conditions in small amplitude waves. Moreover, the S175 container ship results are compared with the available experimental data and agreed well with the experimental results in forward speed case. It has been observed that PRETTI code is over-estimating motion and load responses especially around the resonant frequency due to the surge motion influence in the memory forces evaluations. In the Froude-Krylov nonlinear level predictions, it has been observed that PRETTI diverges from the experimental results when the wave steepness is higher than 0.08 due to the linear radiation and diffraction forces. Based on the same framework, a more advanced nonlinear time-domain panel code (LARes L3) was developed in order to investigate the effects of quasi-non-linear diffraction and radiation forces in large amplitude ship simulations. A new mesh generator was introduced in order to cut and correct the original panels under the still water level in the updated position of the ship after displacements and rotations. The quasi-non-linear diffraction and radiation forces were calculated at the pre-defined position cases and stored in a database. In order to lower the computational cost multi-dimensional integration and interpolation codes were generated. The S-175 containership was tested in 120 different position cases and resulting hydrodynamic coefficients and forces were stored in the database. The results of the LARes L3 model were compared with the available experimental data using the S-175 containership in forward speed. The computed motion responses showed a good agreement with the experimental data. Moreover, three of the developed models are compared with the experiments and their performances were investigated with respect to the increasing wave slope. In addition to that, the effect of the wave length and ship speed in large amplitude waves are investigated in detail. Non-linear behaviors of the codes were compared with the experimental results which showed a good agreement. Finally, the Vertical Shear Force (VSF) and Vertical Bending Moment (VBM) responses were investigated in large amplitude motions. It was observed that, in the validation section, numerical model peak amplitudes showed well agreement with the experimental results, but they were observed to be shifted to the higher frequencies compared to the experimental results. The reason for that was attributed to the longitudinal mass distribution on the ship in the experimental setup which had not been provided in detail in the published experimental results.
Download or read book Nonlinear Time domain Simulation of Ship Capsizing in Beam Seas written by Woei-Min Lin and published by . This book was released on 1997 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large amplitude ship motions in the time domain written by Allan R. Magee and published by . This book was released on 1991 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of time-domain analysis of predicting ship motions is investigated. In the method, the hydrodynamic problem is solved directly in the time domain as an initial value problem starting from rest rather than using the more conventional frequency-domain formulation.
Download or read book Numerical Simulation of Large Amplitude Ship Motions written by Shukui Liu and published by LAP Lambert Academic Publishing. This book was released on 2012-04 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reliable prediction of the seakeeping behavior of ships in real seas is a demanding task for naval architects and of great interest to ship owners/operators, as it affects both the design and operation of ships. In this work, a set of methods, namely, a time domain transient Green function solver, alternatively a time domain hybrid solver for zero speed problems and the adopted hybrid solver for nonzero forward speed problem, are developed to study the seakeeping behavior of ships and floating structures in waves. Validation cases cover both simple mathematical geometries and practical ship hulls, either without or with forward speed. Obtained results include radiation/diffraction forces, wave making resistance, motion simulation and added resistance (drift force). It is proved that by properly selecting a solver the developed package is capable of simulating large amplitude motions of ships or floating structures in waves thus it can serve as an advanced tool for the assessment of ship design and operation. This work is expected to offer researchers in similar field a state of art review of the problem and certain amount of inspiration in terms of numerical implementation.
Download or read book Large Amplitude Ship Motions and Capsizing in Severe Sea Conditions written by Jean Otto de Kat and published by . This book was released on 1988 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ship Motions and Capsizing in Astern Seas written by University of California, Berkeley. Department of Naval Architecture and Offshore Engineering and published by . This book was released on 1974 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonlinear Time Domain Simulation of Ship Capsizing in Beam Seas written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ship design practice has been to measure stability by static criteria and to compensate for dynamic effects through a margin of safety. However, there is a fundamental difference between static and dynamic stability. Certain factors which result in favorable static stability characteristics may actually present greater danger when considered in light of a dynamic analysis. The traditional linear strip theory method is not suitable for assessing ship capsizing. This report presents a state of the art nonlinear simulation method, LAMP (Large Amplitude Motion Program), for the evaluation of ship operation in extreme seas. The intent of the study was to modeZ maritime casualties, including a time domain simulation of a ship capsizing in beam seas. A 400-foot (122-meter) Series 60, C sub B = 0.7 ship with the center of gravity, CG, located amidships and 2.07 ft (0.63 m) below the design waterline is used as an example in this study. This ship satisfies the U.S. Coast Guard's minimum Metacentric Height, or GM, requirement for large cargo ship. It is shown in the report that capsizing can happen due to dynamic effects even for ships that satisfy the minimum GM requirement.
Download or read book Time domain simulation of ship motions in waves written by Edward John Ballard and published by . This book was released on 2002 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large amplitude ship motions and capsizing in severe sea conditions written by Jean O. DeKat and published by . This book was released on 1988 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contemporary Ideas on Ship Stability and Capsizing in Waves written by Marcelo Almeida Santos Neves and published by Springer Science & Business Media. This book was released on 2011-07-03 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last decade significant progress has been made in the field of ship stability. Yet in spite of the progress made, numerous scientific and practical challenges still exist with regard to the accurate prediction of extreme motion and capsize dynamics for intact and damaged vessels, the probabilistic nature of extreme events, criteria that properly reflect the physics and operational safety of an intact or damaged vessel, and ways to provide relevant information on safe ship handling to ship operators. This book provides a comprehensive review of the above issues through the selection of representative papers presented at the unique series of international workshops and conferences on ship stability held between 2000 and 2009. The editorial committee has selected papers for this book from the following events: STAB 2000 Conference (Launceston, Tasmania), 5th Stability Workshop (Trieste, 2001), 6th Stability Workshop (Long Island, 2002), STAB 2003 Conference (Madrid), 7th Stability Workshop (Shanghai, 2004), 8th Stability Workshop (Istanbul, 2005), STAB 2006 Conference (Rio de Janeiro), 9th Stability Workshop (Hamburg, 2007), 10th Stability Workshop (Daejeon, 2008), and STAB 2009 Conference (St. Petersburg). The papers have been clustered around the following themes: Stability Criteria, Stability of the Intact Ship, Parametric Rolling, Broaching, Nonlinear Dynamics, Roll Damping, Probabilistic Assessment of Ship Capsize, Environmental Modelling, Damaged Ship Stability, CFD Applications, Design for Safety, Naval Vessels, and Accident Investigations.
Download or read book A Time Domain Simulation of Ship Motions in Waves written by and published by . This book was released on 1988 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ship Motions and Capsizing in Astern Seas written by and published by . This book was released on 1974 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical and experimental study of ship motions and capsizing in extreme seas has been conducted. The analysis of linear and quasi-linear one-dimensional roll models has revealed motion anomalies not apparent from the usual linearized ship motion theory. Extensive tests have been conducted using two radio-controlled models in the wind generated seas of San Francisco Bay. Directional spectra were computed, using a variety of techniques, from the wave measurements by an array of wave gages. Comparisons of the experimentally determined motions and a linear strip theory prediction are presented. A time domain numerical simulation program for motions and capsizing has been used to investigate motions in a variety of wave group configurations. The results show good agreement with observed capsizing phenomena and have revealed a number of important characteristics associated with large geometry changes in waves.
Download or read book Time domain Simulation of Wave induced Ship Motions by a Rankine Panel Method written by Junshi Wang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, a numerical program has been developed to simulate the wave-induced ship motions in the time domain. Wave-body interactions have been studied for various ships and floating bodies through forced motion and free motion simulations in a wide range of wave frequencies. A three-dimensional Rankine panel method is applied to solve the boundary value problem for the wave-body interactions. The velocity potentials and normal velocities on the boundaries are obtained in the time domain by solving the mixed boundary integral equations in relation to the source and dipole distributions. The hydrodynamic forces are calculated by the integration of the instantaneous hydrodynamic pressures over the body surface. The equations of ship motion are solved simultaneously with the boundary value problem for each time step. The wave elevation is computed by applying the linear free surface conditions. A numerical damping zone is adopted to absorb the outgoing waves in order to satisfy the radiation condition for the truncated free surface. A numerical filter is applied on the free surface for the smoothing of the wave elevation. Good convergence has been reached for both forced motion simulations and free motion simulations. The computed added-mass and damping coefficients, wave exciting forces, and motion responses for ships and floating bodies are in good agreement with the numerical results from other programs and experimental data.
Download or read book Contemporary Ideas on Ship Stability written by Vadim L. Belenky and published by Springer. This book was released on 2019-01-01 with total page 931 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a selection of research papers presented at the 11th and 12th International Ship Stability Workshops (Wageningen, 2010 and Washington DC, 2011) and the 11th International Conference on Stability of Ships and Ocean Vehicles (Athens, 2012). The book is directed toward the ship stability community and presents innovative ideas concerning the understanding of the physical nature of stability failures and methodologies for assessing ship stability. Particular interest of the readership is expected in relation with appearance of new and unconventional types of ships; assessment of stability of these ships cannot rely on the existing experience and has to be based on the first principles. As the complexity of the physical processes responsible for stability failure have increasingly made time-domain numerical simulation the main tool for stability assessment, particular emphasis is made on the development an application of such tools. The included papers have been selected by the editorial committee and have gone through an additional review process, with at least two reviewers allocated for each. Many of the papers have been significantly updated or expanded from their original version, in order to best reflect the state of knowledge concerning stability at the time of the book’s publication. The book consist of four parts: Mathematical Model of Ship Motions in Waves, Dynamics of Large Motions, Experimental Research and Requirements, Regulations and Operations.
Download or read book Nonlinear Time domain Simulation of Fishing Vessel Capsizing in Quartering Seas written by and published by . This book was released on 1998 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ship design practice has been to measure stability by static criteria and to compensate for dynamic effects through a margin of safety. However, there is a fundamental difference between static and dynamic stability. Certain factors that result in favorable static stability characteristics may actually present greater danger when considered in light of a dynamic analysis. Traditional linear strip theory methods are not suitable for assessing ship capsizing. The main objective of the present project has been to investigate the capabilities of the 3-D nonlinear time domain Large Amplitude Motion Program (LAMP) for the evaluation of fishing vessels operating in extreme waves. The project's focus was building upon the previous LAMP development and extending it to the modeling of maritime casualties, including a time domain simulation of a ship capsizing in stern quartering seas. This modeling capability will allow both the analysis of recorded casualties and the identification of potential safety concerns.
Download or read book Time domain Simulation of Nonlinear Ship Motions and Wave Loads written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the assessment of the ability of a ship structure to withstand specified sea environments with an acceptable risk of failure, accurately predicted loads are vital. Of paramount importance are extreme loads on the hull structure, which usually occur when a ship undergoes large heaving & pitching motions in rough seas, sometimes accompanied by impacts between the bow & waves. This paper describes the application of strip theory to time domain calculations of non-linear ship motions and hull-girder loads in head seas. In this approach, the differential equations of ship motion are solved numerically by calculating hydrodynamic forces & coefficients at each time step by strip theory, taking into account nonlinearities relating to large relative motion between waves & the ship hull. The results indicate the usefulness of this approach compared to the conventional linear frequency-domain approach.
