Title Coupled nonlinear parametric resonance model for container ships : doctoral disertation Title (english) Spregnuti nelinearni model parametarske rezonancije kod kontejnerskih brodova : doktorska disertacija Author Anton Turk Mentor Jasna Prpić-Oršić (mentor)Mentor Carlos Guedes Soares (komentor) Committee member Jasna Prpić-Oršić (predsjednik povjerenstva)Committee member Bruno Čalić (član povjerenstva)Committee member Roko Dejhalla (član povjerenstva)Granter University of Rijeka Defense date and country 2012-01-01, Croatia Scientific / art field, TECHNICAL SCIENCES Universal decimal classificationUDC ) 629 - Transport vehicle engineering Abstract SUMMARY The objective of the present work is to develop and validate a computational tool for the calculation of large amplitude parametric rolling motions that can be used in conceptual design in a computationally efficient and robust manner. The contribution of this work to the general body of knowledge is in the development of a theory that captures hull interaction effects for a given range of ship speeds, sea states and loading conditions, where
... More interaction effects are likely to materialize in certain non-linear phenomena of dynamic instability known as parametric resonance, while retaining the numerical efficiency of strip theory. The numerical code is based on an hybrid model which transfers frequency domain data to time domain and includes the so called Froude-Krylov nonlinear part of the loading in time domain. The use of a simplified 2½D method showed slight improvement over the classical 2D method with the disadvantage of being more computationally intense than standard strip theory. Furthermore, the implementation of strip theory, with respect to functionality, has been shown to require a more advanced method for including roll damping. The viscous contribution proved far superior in terms of the effect it has on the proneness towards parametric rolling. The problem of viscous roll damping is separated in two models, first when the experimental results are not known with the blending method and second when the roll decrement test are at hand. An extensive experimental program of the Parametric Rolling on a C11 Class Containership was utilized to investigate and explain two consisting inseparable treatments of the damping and seakeeping simulations, respectively. The validation has shown good agreement with the experimental results for roll, both in the experiments where parametric roll resonance occurred and in the experiments where it did not occur. The simulated results, including polychromatic and irregular wave excitation, and the subsequent analysis, provided insight and improved the understanding of the parametric roll resonance mechanism, as well provided the basis for setting a probabilistic methodology proposition. Less Abstract (croatian) Cilj ovog rada bio je razviti i validirati računalni alat za određivanje velikih amplituda odziva uslijed parametarskog ljuljanja koji se može koristiti u konceptualnom dizajnu na računalno učinkovit i robustan način. Doprinos ovog rada je u razvoju teorije koja hvata dominantne čimbenike interakcije brodskog trupa i okoline za određeni raspon brzina brodova, stanja mora i stanja krcanja. Efekti interakcije manifestiraju se nelinearnim
... More fenomenom dinamičke nestabilnosti, parametarskim ljuljanjem, dok se pritom, zadržava numerička učinkovitost vrpčaste teorije. Numerički kod temelji se na hibridnom modelu s prijenosom hidrodinamičkih podataka iz frekventne domene u vremensku domenu uključujući tzv. Froude-Krylovljevu nelinearnu silu u vremenskoj domeni. Korištenje pojednostavljene 2½D metode rezultirao je blagim napredakom u odnosu na klasičnu 2D metodu nauštrb vremenski intenzivniji simulacije. Nadalje, provedba vrpčaste teorije zahtijeva napredniju metodu, kod definiranje prigušenja ljuljanja. Doprinos viskoznih efekata pokazao se kao daleko superiorniji u odnosu na ostale nelinarne učinke koje rezultiraju parametarskim ljuljanjem. Problem viskoznihm prigušenja ljuljanja je odvojen u dva modela, prvo kada eksperimentalni rezultati nisu poznati korištenjem tzv. "blending“ metode i drugi kada su poznati testovi zamiranja ljuljanja. Opsežni eksperimentalni program koristiti za istraživanje i objašnjenje dva nerazdvojiva aspekta simulacija prigušnja i pomorstvenosti. Eksperimenti su provedeni u okviru projekta pod nazivom “Experimental Assessment of the Parametric Rolling on a C11 Class Containership”. Općenito, validacija svih računalnih simulacija je pokazala vrlo dobro slaganje s odrađenim eksperimentalnim mjerenjima. Simulirani rezultati uključujući polihromatsku i nepravilnu valnu uzbudu kao i naknadne analize pružaju uvid i bolje razumijevanje mehanizma parametske rezonancije, kao temelj prijedloga postavljene vjerojatnosne metodologije. Less Keywords
container ships
Language english URN:NBN urn:nbn:hr:188:533168 Promotion 2012 Study programme Title: Postgraduate university (doctoral) study Catalog URL https://libraries.uniri.hr/cgi-bin/ucat/unilib.cgi?form=D1130108098 Type of resource Text Extent 212 str; 30 cm File origin Born digital Access conditions Closed access Terms of use Created on 2017-01-19 19:24:22
