Abstract: Results from the development and application of coupled-mode models to predict propagation of water waves in nearshore/coastal environment with variable bathymetry and other inhomogeneities are presented, including interaction with marine structures. This method models reflection, refraction, diffraction and dispersion phenomena, without introducing mild-slope type assumptions. The theory is based on an improved representation of the field in a series of local vertical modes, enhanced by appropriate terms to satisfy boundary conditions on the free surface and the sloping bottom. The additional modes significantly accelerate the convergence of the modal expansion and make the method suitable for horizontally large-scale applications. Next, the problem of propagation and interaction in non-homogeneous environment is reformulated as a system of partial differential equations on the horizontal plane, having the property to reduce to mild-slope type models in subregions where bathymetry and other parameters are slowly varying,  saving computational cost. Various examples  are presented and discussed demonstrating the applicability of the present method, including effects of waves on marine floating or fixed structures in an environment characterized by variable bottom topography. Recent results concerning the extension of the model to treat effects of sheared currents on waves are also presented.

Short bio: Professor Kostas BELIBASSAKIS (kbel@fluid.mech.ntua.gr): School of Naval Architecture & Marine Engineering, National Technical University of Athens (NTUA). He has been visiting Professor in University of Toulon  (2014-2018), Ecole Cenrale Marseille (2014) and Brunel University (2018). Diploma in Naval Architecture and Marine Engineering  NTUA (1986) and  PhD from the same University (NTUA 1992). He has participated in number of research projects funded by EU and Greek national resources (Ministry of Education, Secretariat for Research and Technology, Public & Private Sector, etc). His research interests include: wave propagation in marine environment (water waves in general bathymetry and acoustic waves in layered waveguides), free-surface hydrodynamics and wave-body interaction, probabilistic description of the marine environment, novel marine thruster performance, lifting flows and biomimetic  systems. He teaches Modelling of Wave Phenomena in the Sea, Ship Resistance & Propulsion,  Ship and Marine Hydrodynamics  and  Ship Dynamics (at NTUA). CV available at:  http://arion.naval.ntua.gr/~kbel/