A boundary element method for the hydrodynamic analysis of floating bodies in variable bathymetry regions

Thermos, Leonidas; Θερμός, Λεωνίδας

dc.contributor.author	Thermos, Leonidas	en
dc.contributor.author	Θερμός, Λεωνίδας	el
dc.date.accessioned	2018-10-09T09:09:43Z
dc.date.available	2018-10-09T09:09:43Z
dc.date.issued	2018-10-09
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/47749
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.15622
dc.rights	Default License
dc.subject	BEM	en
dc.subject	WEC	en
dc.subject	3D BEM	en
dc.subject	Hydrodynamic analysis	en
dc.subject	Variable bathymetry region	el
dc.title	A boundary element method for the hydrodynamic analysis of floating bodies in variable bathymetry regions	en
heal.type	bachelorThesis
heal.classification	Hydrodynamics	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2017-11-23
heal.abstract	Floating structures, operating in a nearshore coastal environment of variable bathymetry, and their hydrodynamic behavior constitute an important subject in marine and offshore structure design and performance. The study of wave energy converters, exploiting the wave energy potential and converting it into electrical energy, is of particular interest in ocean and coastal engineering. In the present thesis a Boundary Element Method is presented and discussed, for treating problems concerning waves-floating body-seabed interactions in a variable bathymetry environment and arbitrary body geometry. As a result the hydrodynamic behavior of the body is calculated. Specifically, in Chapter 1 a state-of-the-art review concerning offshore and coastal floating structures and wave energy converters of the kind of point absorbers is presented. Also, a brief review of the boundary element method is given. In Chapter 2, an absorbing layer technique, in conjunction with a boundary element method is presented, and optimized in the case of two-dimensional wavemaker problem, for which an analytical solution is available (both for the flap-type and the piston-type wavemakers). Comparing the numerical against the analytical solution useful conclusions are derived for the optimum selection of absorbing layer parameters. A similar procedure is followed in Chapter 3, where a 3D hybrid boundary element - absorbing layer method is presented, treating the problem of a floating cylinder, oscillating in finite depth. The method is based on 4-node quadrilateral elements and piecewise constant dipole distribution, and details concerning the integration formulae are provided in Appendix A. Again, in the case of vertical cylinder the analytic solution is used to validate the numerical method in constant depth. Then, in Chapter 4, the latter method is extended to the hydrodynamic analysis of floating body in variable bathymetry. The present 3D hybrid boundary element - absorbing layer method is used for the solution of the radiation problems (for all 6 dofs) and the diffraction problem, which is formulated using the solution concerning the propagating wave over the variable bathymetry. The latter is obtained by application of the coupled-mode model by Athanassoulis & Belibassakis (1999), which is presented in Appendix B. The present thesis ends with conclusions and suggestions for future work.	en
heal.advisorName	Belibassakis, Kostas	el
heal.committeeMemberName	Athanassoulis, Gerassimos	en
heal.committeeMemberName	Gerassimos, Politis	en
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Ναυτικής και Θαλάσσιας Υδροδυναμικής. Εργαστήριο Ναυτικής και Θαλάσσιας Υδροδυναμικής	el
heal.academicPublisherID	ntua
heal.numberOfPages	130 σ.
heal.fullTextAvailability	true