2018-2019 / HULG0338-1

Seakeeping : Theory and numerical modelling

Duration

20h Th, 15h Pr

Number of credits

 Specialised master in naval construction (EMSHIP - Erasmus mundus)5 crédits  

Lecturer

P. Ferrant, L. Gentaz

Language(s) of instruction

English language

Organisation and examination

Teaching in the second semester

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit contents

* Objectifs, theoretical frame * Short review of linear systems thory * Formulation of the boundary value problem. Linearization * Frequency domain appoach - Definition of diffraction and radiation sub-problems - Hydrodynamic loads : addes mass and damping

  • Calculation of motions
  • Relations between elementary solutions
* Time domain approach - Forced motion of a floating body - Formulation of the diffraction problem in the time domain - Equations of motion - Relations to frequency domain reponse * Second order effects : - Drift forces - Low and high frequency loading in irregular waves * Introduction to Nonlinear Models for Ship Seakeeping - Nonlinear Hydrostatics and Froude-Krylov loading - Weak scatterer hypothesis * Fully nonlinear appoaches * Practical use of numerical tools dedicated to ship seakeeping under potential flow theory. Meshing ; convergence studies ; Influence of non linear effects ; comparisons with results from the literature ; discussion ; advantages and drawbacks of the model.

Learning outcomes of the learning unit

The objective here is to give a complete presentation of the presentation of the available models for the determination of the ship's response in a seaway, emphasizing the advantages and drawbacks of each approach. First, we give a complete presentation of the linearized theory of wave-body interactions, treated in a deterministic sense. 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 avaible nonlinear theories of seakeeping is given. Different levels of approximation are described, from the simple addition of nonlinear hydrostatics to fully nonlinear time domain models. In addition to the theoretical part, pratical exercises are proposed to the students, based on some typical state of the art numerical software for ship seakeeping.

Prerequisite knowledge and skills

Elements on water waves modelling given in the EMSHIP S2-1 lecture "water waves ans sea state models for ship design" described before will be useful here.

Planned learning activities and teaching methods

Mode of delivery (face-to-face ; distance-learning)

Recommended or required readings

"Sea Loads on Ships and Offshore Structures" by O.M. Faltinsen, Cambridge ocean technology series.

Assessment methods and criteria

Written exam (1h) + report of practical training.

Work placement(s)

Organizational remarks

Contacts

P. Ferrant & L. Gentaz