Nonlinear Waves and Offshore Structures
Nonlinear Waves and Offshore Structures

Author: Cheung Hun Kim

Publisher: World Scientific

Published: 2008

Total Pages: 539

ISBN-13: 9810248849

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The responses of offshore structures are significantly affected by steep nonlinear waves, currents and wind, leading to phenomena such as springing and ringing of TLPs, slow drift yaw motion of FPSOs and large oscillations of Spar platforms due to vortex shedding. Research has brought about significant progress in this field over the past few decades and introduced us to increasingly involved concepts and their diverse applicability. Thus, an in-depth understanding of steep nonlinear waves and their effects on the responses of offshore structures is essential for safe and effective designs.This book deals with analyses of nonlinear problems encountered in the design of offshore structures, as well as those that are of immediate practical interest to ocean engineers and designers. It presents conclusions drawn from recent research pertinent to nonlinear waves and their effects on the responses of offshore structures. Theories, observations and analyses of laboratory and field experiments are expounded such that the nonlinear effects can be clearly visualized.

The Effects of Random and Nonlinear Waves on Coastal and Offshore Structures
The Effects of Random and Nonlinear Waves on Coastal and Offshore Structures

Author: Benjamin Y. -H. Chen

Publisher:

Published: 1987

Total Pages: 23

ISBN-13:

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Wave effects on coastal and offshore structures have been studied for more than two decades. Nevertheless, the dynamic behaviors of those structures due to a real sea state, considering the features of randomness, nonlinearity, and directionality, have seldom been investigated. In this report, random and nonlinear wave effects on those structures have been examined analytically. The first part presents a new model of a linear random wave force transformation on a sloping beach as the waves propagate from offshore toward the shore. The second part investigates the effect of nonlinear wave interactions on the dynamic response of a fixed offshore structure. The third part examines the effect of wave groups and an associated forced second-order wave system on the dynamic response of a fixed offshore structure. The results of this report show that random and nonlinear waves play important roles on the dynamic behaviors of coastal and offshore structures. Keywords: Ocean waves, Coastal structures; Random waves; Wave force transformation.

Nonlinear Dynamics of Compliant Offshore Structures
Nonlinear Dynamics of Compliant Offshore Structures

Author: Patrick Bar-Avi

Publisher: Routledge

Published: 2017-12-04

Total Pages: 181

ISBN-13: 1351428241

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This monograph provides a general background to the modelling of a special class of offshore structures known as compliant structures. External forcing is resisted by buoyancy and tension forces which increase when the structure is slightly offset from its equilibrium. The technical development given in this book is presented in such a way as to highlight the adaptability of the modelling, and the reader is shown how the techniques described can be applied to a variety of different offshore structures.

Nonlinear and Stochastic Dynamics of Compliant Offshore Structures
Nonlinear and Stochastic Dynamics of Compliant Offshore Structures

Author: Seon Mi Han

Publisher: Springer Science & Business Media

Published: 2013-04-17

Total Pages: 281

ISBN-13: 9401599122

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The purpose of this monograph is to show how a compliant offshore structure in an ocean environment can be modeled in two and three di mensions. The monograph is divided into five parts. Chapter 1 provides the engineering motivation for this work, that is, offshore structures. These are very complex structures used for a variety of applications. It is possible to use beam models to initially study their dynamics. Chapter 2 is a review of variational methods, and thus includes the topics: princi ple of virtual work, D'Alembert's principle, Lagrange's equation, Hamil ton's principle, and the extended Hamilton's principle. These methods are used to derive the equations of motion throughout this monograph. Chapter 3 is a review of existing transverse beam models. They are the Euler-Bernoulli, Rayleigh, shear and Timoshenko models. The equa tions of motion are derived and solved analytically using the extended Hamilton's principle, as outlined in Chapter 2. For engineering purposes, the natural frequencies of the beam models are presented graphically as functions of normalized wave number and geometrical and physical pa rameters. Beam models are useful as representations of complex struc tures. In Chapter 4, a fluid force that is representative of those that act on offshore structures is formulated. The environmental load due to ocean current and random waves is obtained using Morison's equa tion. The random waves are formulated using the Pierson-Moskowitz spectrum with the Airy linear wave theory.

Nonlinear Methods in Offshore Engineering
Nonlinear Methods in Offshore Engineering

Author: Subrata Kumar Chakrabarti

Publisher: Elsevier Publishing Company

Published: 1990

Total Pages: 572

ISBN-13:

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The purpose of this book is to report the state-of-the-art of the available and emerging techniques for the determination of extreme responses of a marine structure. This book is intended to be a textbook on the analysis of nonlinear problems generally encountered in an offshore structure design. The book stresses the application of nonlinear theories to practical design problems.

Nonlinear Dynamics of Compliant Offshore Structures
Nonlinear Dynamics of Compliant Offshore Structures

Author: Patrick Bar-Avi

Publisher: CRC Press

Published: 1997

Total Pages: 192

ISBN-13:

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Outlines the theoretical basis for modelling nonlinear dynamics in a range of compliant offshore structures, and details the application of the theory to the physical environment.

Advances in Numerical Simulation of Nonlinear Water Waves
Advances in Numerical Simulation of Nonlinear Water Waves

Author: Qingwei Ma

Publisher: World Scientific

Published: 2010

Total Pages: 700

ISBN-13: 9812836500

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Ch. 1. Model for fully nonlinear ocean wave simulations derived using Fourier inversion of integral equations in 3D / J. Grue and D. Fructus -- ch. 2. Two-dimensional direct numerical simulations of the dynamics of rogue waves under wind action / J. Touboul and C. Kharif -- ch. 3. Progress in fully nonlinear potential flow modeling of 3D extreme ocean waves / S.T. Grilli [und weitere] -- ch. 4. Time domain simulation of nonlinear water waves using spectral methods / F. Bonnefoy [und weitere] -- ch. 5. QALE-FEM method and its application to the simulation of free-responses of floating bodies and overturning waves / Q.W. Ma and S. Yan -- ch. 6. Velocity calculation methods in finite element based MEL formulation / V. Sriram, S.A. Sannasiraj and V. Sundar -- ch. 7. High-order Boussinesq-type modelling of nonlinear wave phenomena in deep and shallow water / P.A. Madsen and D.R. Fuhrman -- ch. 8. Inter-comparisons of different forms of higher-order Boussinesq equations / Z.L. Zou, K.Z. Fang and Z.B. Liu -- ch. 9. Method of fundamental solutions for fully nonlinear water waves / D.-L. Young, N.-J. Wu and T.-K. Tsay -- ch. 10. Application of the finite volume method to the simulation of nonlinear water waves / D. Greaves -- ch. 11. Developments in multi-fluid finite volume free surface capturing method / D.M. Causon, C.G. Mingham and L. Qian -- ch. 12. Numerical computation methods for strongly nonlinear wave-body interactions / M. Kashiwagi, C. Hu and M. Sueyoshi -- ch. 13. Smoothed particle hydrodynamics for water waves / R.A. Dalrymple [und weitere] -- ch. 14. Modelling nonlinear water waves with RANS and LES SPH models / R. Issa [und weitere] -- ch. 15. MLPG_R method and Its application to various nonlinear water waves / Q.W. Ma -- ch. 16. Large Eddy simulation of the hydrodynamics generated by breaking waves / P. Lubin and J.-P. Caltagirone -- ch. 17. Recent advances in turbulence modeling for unsteady breaking waves / Q. Zhao and S.W. Armfield -- ch. 18. Freak waves and their interaction with ships and offshore structures / G.F. Clauss

Nonlinear Analysis of Offshore Structures
Nonlinear Analysis of Offshore Structures

Author: Bjørn Skallerud

Publisher:

Published: 2002

Total Pages: 348

ISBN-13:

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The importance of accounting for nonlinear effects in offshore structures has increased due to their higher utilization and extended service lives. This text addresses new methods for advanced analysis of offshore structures developed during the 1990s.

An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines
An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines

Author: Enzo Marino

Publisher: Firenze University Press

Published: 2010

Total Pages: 232

ISBN-13: 8866550515

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This thesis presents a numerical model capable of simulating offshore wind turbines exposed to extreme loading conditions. External condition-based extreme responses are reproduced by coupling a fully nonlinear wave kinematic solver with a hydro-aero-elastic simulator. First, a two-dimensional fully nonlinear wave simulator is developed. The transient nonlinear free surface problem is formulated assuming the potential theory and a high-order boundary element method is implemented to discretize Laplace's equation. For temporal evolution a second-order Taylor series expansion is used. The code, after validation with experimental data, is successfully adopted to simulate overturning plunging breakers which give rise to dangerous impact loads when they break against wind turbine substructures. Emphasis is then placed on the random nature of the waves. Indeed, through a domain decomposition technique a global simulation framework embedding the numerical wave simulator into a more general stochastic environment is developed. The proposed model is meant as a contribution to meet the more and more pressing demand for research in the offshore wind energy sector as it permits taking into account dangerous effects on the structural response so as to increase the global structural safety level.