Hydroelastic interaction between ocean waves and large floating structures in the inhomogeneous ocean environment

• Main Authors: Karperaki, Angeliki, Καρπεράκη, Αγγελική
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: National Technical University of Athens (NTUA) 2021
• Subjects: Πλωτές κατασκευές; Πεπερασμένα στοιχεία; Υδροελαστικότητα; Αριθμητική προσομοίωση; Θαλάσσια μηχανική; Παράκτια μηχανική; Floating structures; Finite element method; Hydroelasticity; Numerical simulation; Ocean engineering; Coastal engineering; Μαθηματικά; Φυσικές Επιστήμες; Μοντελοποίηση και Προσομοίωση; Περιβαλλοντική Μηχανική; Επιστήμες Μηχανικού και Τεχνολογία; Mathematics; Natural Sciences; Modeling and Simulation; Environmental Engineering; Engineering and Technology; Ice Shelves
• Online Access: http://hdl.handle.net/10442/hedi/51029; https://doi.org/10.12681/eadd/51029

Ocean wave interaction with flexible floating structures finds numerous applications in marine science and technology as well as in ocean and polar engineering. The adjacent fields focus on the study of wave-structure-seabed interaction, targeting man-made structures and geophysical formations, such as ice shelves and ice floes, respectively. Very Large Floating Structures and ice formations share two distinct hydrodynamic features; their large dimensions compared to the incident wavelengths and their relatively low bending rigidity which renders flexural modes dominant. The foundations of the aforementioned problems in both fields are set in hydroelasticity and are characterised by challenges like the inherently large computational domains and the heterogeneity manifested in both the ocean waveguide and the structure. The treatment of heterogeneity in terms of variable bathymetry for the ocean environment and varying material properties and geometry for the structure remain formidable tasks even in the linear regime. The thesis focuses on the treatment of hydroelastic interaction between ocean waves and large floating structures in an inhomogeneous setting. While both time and frequency domain analyses were undertaken, the present focuses primarily on the latter. Parts I-III, representing the bulk of the conducted research, are set in the frequency domain, while Part IV outlines developed numerical tools targeting transient phenomena. In the frequency domain, confined in the linear regime potential theory is employed for the hydrodynamic modelling. The floating body is assumed to be thin and within the limits of elastic plate models. Depending on the structure slenderness and the excitation wavelength-to-plate thickness ratio, the elastic body is modelled using either the Classical Thin Plate Theory (CPT) or the higher order Reissner-Mindlin Plate theory accounting for first order shear deformation effects (FSDT). Furthermore, The slenderness of the structure justifies the adopted negligible-draft assumption. ...