Water wave kinematics is a central field of study in ocean and coastal engineering. The wave forces on structures as well as sand erosion both on coastlines and in the ocean are to a large extent governed by the local distribution of velocities and accelerations of the water particles. Our knowledge of waves has generally been derived from measurements of the water surface elevations. The reason for this is that the surface elevations have been of primary interest and fairly cheap and reliable instruments have been developed for such measurements. The water wave kinematics has then been derived from the surface elevation information by various theories. However. the different theories for the calculation of water particle velocities and acceleration have turned out to give significant differences in the calculated responses of structures. In recent years new measurement techniques have made it possible to make accurate velocity measurements. Hence. the editors deemed it to be useful to bring together a group of experts working actively as researchers in the field of water wave kinematics. These experts included theoreticians as well as experimentalists on wave kinematics. It was also deemed useful to include experts on the response of structures to have their views from a structural engineering point of view on what information is really needed on water wave kinematics.

This book comprises selected proceedings of the Fourth International Conference in Ocean Engineering (ICOE2018), focusing on emerging opportunities and challenges in the field of ocean engineering and offshore structures. It includes state-of-the-art content from leading international experts, making it a valuable resource for researchers and practicing engineers alike.

Coastal and ocean processes are heavily influenced by the kinematics of waves. In order to understand these processes, researchers place a variety of instruments in the sea in an attempt to measure the waves. These instruments all measure a small set of physical quantities at a small number of locations. The balance of the kinematics must be predicted through analysis of the measured records. Most of the currently used methods of analysis rely on the superposition of linear waves to recreate complex seas. These methods are compromised by linearizing approximations to the free surface boundary conditions. Fidelity in the interpretation of wave measurements is enhanced by insisting that the analysis satisfies the full nonlinear free surface boundary conditions. The Local Fourier method for irregular wave kinematics is introduced and expanded to include the interpretation of records from arrays of instruments. It is a local method, in that a separate solution is sought that fits the measured record(s) in a small local window in time, rather than attempting to find a single solution for a large segment of the record. Each window solution satisfies the full set of governing equations for gravity waves, including the nonlinear free surface boundary conditions. The solution in each window is a potential function whose form is based upon a Stokes style expansion for intersecting waves. The parameters of the potential function are found by a nonlinear optimization that seeks the solution that matches the measured record and satisfies the full free surface boundary conditions.

Brest, 29 au 29 novembre 2000. C'est aujourd'hui une certitude que certaines vagues outrepassent en hauteur et en cambrure les prédictions fondées sur les modèles courants. L'amélioration de la compréhension des raisons, des mécanismes, et des circonstances de leur apparition se doit donc d'être une priorité de recherche. Le colloque Rogue Waves 2000 a rassemblé à Brest nombre des scientifiques et ingénieurs actifs sur le sujet, qui y ont trouvé l'occasion de confronter et discuter leurs avancées les plus récentes en termes de définition, de statistiques, de modélisation et de prédiction de ces vagues anormales. Mots-clés : vagues, extrêmes, non-linéarités, vagues anormales, vagues scélérates.

Coastal and ocean processes are heavily influenced by the kinematics of waves. In order to understand these processes, researchers place a variety of instruments in the sea in an attempt to measure the waves. These instruments all measure a small set of physical quantities at a small number of locations. The balance of the kinematics must be predicted through analysis of the measured records. Most of the currently used methods of analysis rely on the superposition of linear waves to recreate complex seas. These methods are compromised by linearizing approximations to the free surface boundary conditions. Fidelity in the interpretation of wave measurements is enhanced by insisting that the analysis satisfies the full nonlinear free surface boundary conditions. The Local Fourier method for irregular wave kinematics is introduced and expanded to include the interpretation of records from arrays of instruments. It is a local method, in that a separate solution is sought that fits the measured record(s) in a small local window in time, rather than attempting to find a single solution for a large segment of the record. Each window solution satisfies the full set of governing equations for gravity waves, including the nonlinear free surface boundary conditions. The solution in each window is a potential function whose form is based upon a Stokes style expansion for intersecting waves. The parameters of the potential function are found by a nonlinear optimization that seeks the solution that matches the measured record and satisfies the full free surface boundary conditions.