Description and contextualization of the subject

The first part of this course is devoted to the interactions between ocean waves and marine structures.

The linearized theory for wave-structure interactions, which is the basis of state of the art software used in the industry, is described in details. In addition, different levels of approximation for the nonlinear problem are described, and the influence of second and higher order nonlinear effects is explained and illustrated.

The second part addresses the modeling of mooring systems, a key step in the design of ships and marine structures.

The objective of the first part is to give a complete presentation of the available models for the determination of marine structures response in a seaway, emphasizing the advantages and drawbacks of each approach.

A complete presentation of the linearized theory of wave-body interactions, treated in a deterministic sense, is first given. Both frequency domain and time domain approaches are described. Fundamental relations between both solutions are systematically emphasized. High and low frequency second order effects are explained and illustrated.

Then, an overview of the available nonlinear theories and numerical models for wave-structure interactions is given. Different levels of approximation are described, from the simple addition of nonlinear hydrostatics to fully nonlinear time domain models.

The second part addresses the modelling of mooring systems. Different options in terms of mooring systems and arrangements are presented in order to give students the main information necessary for undertaking a mooring design process.

For both parts lectures and seminars are completed by practical exercises based on state of the art software for wave-structure interaction and mooring modelling.

Learning outcomes of the subject

To know and explain the potential flow model of wave-structure interactions, together with the hypotheses for its linearization



To know how to analyze the frequency response of a marine wave structure



To know how to analyze the response in time of a marine wave structure and its relationship with the frequency response



To know the technology of mooring and its main problems



To use software to study mooring systems

Temary

Lesson 1 Objectives, theoretical framework

Lesson 2 Short review of linear systems theory

Lesson 3 Formulation of the boundary value problem. Linearization

Lesson 4 Frequency domain approach

a) Definition of diffraction and radiation sub-problems

b) Hydrodynamic loads: added mass and damping

c) Calculation of motions

d) Relations between elementary solutions

Lesson 5 Time domain approach

a) Forced motion of a floating body

b) Formulation of the diffraction problem in the time domain

c) Equations of motion

d) Relation to frequency domain response

Lesson 6 Second order effects

a) Drift forces

b) Low and high frequency loading in irregular waves

Lesson 7 Introduction to nonlinear models

a) Nonlinear hydrostatics and Froude-Krylov loading

b) Weak scattered hypothesis

c) Fully nonlinear models

Lesson 8 Moorings for marine structure

a) Some examples in Oil and Gas energy

b) Different types of mooring systems

c) Offloading operations

d) Some examples in Marine Renewable energy

e) Mooring main functions

f) Mooring arrangement

g) Mooring components

h) Environmental conditions

i) Mooring Design basis

Bibliography

Basic bibliography

J.N. Newman (1977) Marine Hydrodynamics, MIT Press.

O.M. Faltinsen (1990) Sea Loads on Ships and Offshore Structures, Cambridge University Press.

Adrian Biran (2003) Ship Hydrostatics and Stability, Butterworth-Heinemann.

API recommended Practice 2SK (2005) Design and analysis of Stationkeeping Systems for Floating Structures.

Vryhof anchors (2010) Anchor Manual, The Guide to Anchoring.