Ship motions and sea loads
01 Jan 1970-Vol. 78, pp 250-287
TL;DR: In this paper, a new strip theory is presented for predicting heave, pitch, sway, roll, and yaw motions as well as wave-induced vertical and horizontal shear forces, bending moments, and torsional moments for a ship advancing at constant speed with arbitrary heading in regular waves.
Abstract: A new strip theory is presented for predicting heave, pitch, sway, roll, and yaw motions as well as wave-induced vertical and horizontal shear forces, bending moments, and torsional moments for a ship advancing at constant speed with arbitrary heading in regular waves. A computer program based on this theory and with accurate close-fit section representation has been developed. Comparisons between computed values and experimental data show satisfactory agreement in general. In particular, very good agreement is shown for the heave and pitch motions and the vertical loads. Accurate results are also obtained for the coupled sway-roll motions in beam waves. Although comparisons are not yet available for the sway-roll-yaw motions in oblique waves, the satisfactory agreement shown for the horizontal loads in oblique waves suggests that the theory may also predict the horizontal motions quite well.
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09 Jan 2006TL;DR: In this paper, the authors describe a planing vessel with wave resistance and propulsion, and planing vessels with planing, whipping, and springing, as well as a semi-displacement vessel.
Abstract: 1. Introduction 2. Resistance and propulsion 3. Waves 4. Wave resistance and wash 5. Surface effect ships 6. Hydrofoil vessels and foil theory 7. Semi-displacement vessels 8. Slamming, whipping and springing 9. Planing vessels 10. Manoeuvring Appendix References Index.
457 citations
Book•
01 Jan 2011
TL;DR: In this article, the authors present a model and full-scale simulation of ship seakeeping using BEM for full-size ships in sea trials and simulate the effects of wave resistance and propulsion on ship motion.
Abstract: Introduction Overview of problems and approaches Model test and similarity laws Full scale tests Numerical approaches (Computational Fluid Dynamics) Basic equations, Basic techniques Applications. Propeller Flows: Propeller geometry and other basics, Propeller curves Numerical methods for propeller design Lifting line theory Lifting surface theory BEM for propellers Field methods Cavitation Experimental approach Propeller design procedure. Resistance and propulsion: Resistance and propulsion concepts Interaction between ship and propeller Decomposition of resistance Experimental approach Towing tanks and experimental set up Resistance test Method ITTC 1957 Method of Hughes-Prohaska Propulsion test Additional resistance under service conditions Simple design approaches CFD approaches for steady flow Wave resistance computations Viscous flow computations Problems for fast and unconventional ships. Ship Seakeeping: Introduction to seakeeping Experimental approaches (model and full-scale) Waves and seaway Airy waves (harmonic waves of small amplitude) Natural seaway Wind and seaway Wave climate Numerical prediction of ship seakeeping Overview of computational methods Strip method Rankine panel methods Problems for fast and unconventional ships Further quantities in regular waves Ship responses in stationary seaway Simulation methods Long-term distributions Slamming. Manoeuvring: Simulation of manoeuvring with known coefficients Coordinate systems and definitions Body forces and manoeuvring motions Linear motion equations CFD for manoeuvring Experimental approaches Manoeuvring tests for full-scale ships in sea trials Model tests Rudders Computation of body forces Slender-body theory Influence of heel Shallow-water effect Jet thrusters Stop manoeuvres. Boundary element methods: Green function formulation Integral equations Source elements Point source Regular first-order panel Jensen panel Higher-order panel Vortex elements Dipole elements Point dipole. Numerical examples for BEM: Two-dimensional body in infinite flow Theory Numerical implementation.
393 citations
TL;DR: In this paper, the authors performed a fully nonlinear unsteady RANS simulation to predict the ship motions and added resistance of a full scale KRISO container ship model, and to estimate the increase in effective power and fuel consumption due to its operation in waves.
287 citations
TL;DR: In this paper, the authors discuss the dynamics of ship motions that are governed by the equations of motion that balance the external forces and moments acting upon the ship, with the internal force and moment because of gravity and inertia.
Abstract: Publisher Summary This chapter highlights that the oceangoing ships are designed to operate in a wave environment that is frequently uncomfortable and sometimes hostile Unsteady motions and structural loading of the ship hull are two of the principal engineering problems that result Ships generally move with a mean forward velocity and their oscillatory motions in waves are superposed upon a steady flow field The solution of the steady-state problem is itself of interest, particularly with regard to the calculation of wave resistance in calm water The problem of ship motions in waves can be regarded as a superposition of these two special cases, but interactions between the steady and oscillatory flow fields complicate the more general problem The chapter also discusses the dynamics of ship motions that are governed by the equations of motion that balance the external forces and moments acting upon the ship, with the internal force and moment because of gravity and inertia Assuming the ship to be in stable equilibrium in calm water, its weight is balanced by the force of hydrostatic pressure Similarly, the steady drag and propulsive force are balanced These steady forces may be neglected and attention is focused on the unsteady perturbations
250 citations
Lloyd's Register1, National University of Singapore2, Istanbul University3, SINTEF4, Delft University of Technology5, Osaka University6, Technical University of Denmark7, University of Zagreb8, Technical University of Lisbon9, National Technical University of Athens10, Germanischer Lloyd11, University of Strathclyde12
TL;DR: In this paper, the authors present a review of the recent advances in the assessment of loads for ships and offshore structures with the aim to draw the overall technological landscape available for further understanding, validation and implementation by the academic and industrial communities.
226 citations