Procjena pomorstvenih karakteristika kontejnerskog broda

Šalamon, Mateja (2015) Procjena pomorstvenih karakteristika kontejnerskog broda. = Evaluation of seakeeping characteristics of container ship. Master's thesis (Bologna) , Sveučilište u Zagrebu, Fakultet strojarstva i brodogradnje, UNSPECIFIED. Mentor: Degiuli, Nastia.

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Abstract (Croatian)

Utjecaj dinamičkog opterećenja uslijed valova vrlo je značajan te ga je potrebno uzeti u obzir prilikom projektiranja brodskog trupa. To je posebno izraženo kod brodova sa širim pramčanim dijelom kao što su kontejnerski brodovi. Odziv broda na valovima vrlo je kompleksan hidrodinamički problem, a eksperimentalna ispitivanja za procjenu pomorstvenih značajki vrlo su skupa i komplicirana. Daleko jednostavniji i jeftiniji način je korištenje raznih programskih paketa. U ovom radu dane su najvažnije definicije jednadžbe koje opisuju njihanje broda. U programskim paketima WISDAM-X i HydroSTAR izvršena je analiza odziva poniranja i posrtanja u vremenskoj domeni. Analiza je napravljena za četiri različite valne duljine pri čemu su tri analize napravljene za projektnu brzinu, a jedna za brzinu veću od projektne. Sve analize radile se odnose na pravilne valove u pramac. Uspoređeni su odzivi poniranja i posrtanja dobiveni pomoću dva programska paketa u vremenskoj domeni te je dobiven uvid u razlike između potencijalne i viskozne teorije pri određivanju njihanja broda. Kako bi se odredila točnost dvije metode, odzivi poniranja i posrtanja dobiveni numeričkim metodama uspoređeni su s dostupnim eksperimentalnim podacima te je dobiveno zadovoljavajuće poklapanje rezultata. Za opis stanja nekog područja plovidbe koriste se valni spektri te spektri odziva broda. Prilikom projektiranja potrebno je osigurati da se maksimalna vrijednost spektra odziva i maksimalna vrijednost prijenosne funkcije ne nalaze na istoj frekvenciji kako ne bi došlo do rezonancije. Spektri valova i spektri odziva ne ovise o vremenu nego o frekvenciji stoga su u dijagramima prikazani odzivi poniranja i posrtanja u frekvencijskoj domeni. Odzivi poniranja i posrtanja modela 1 i modela 2 dobivenih programskim paketom HydroSTAR u frekvencijskoj domeni uspoređeni su u dijagramima. Maksimalna amplituda odziva javlja se pri različitim frekvencijama u ovisnosti o duljini modela odnosno broda te se može zaključiti da će područje rezonancije ovisiti o glavnim dimenzijama broda.

Abstract

The effect of the dynamic loads due to waves is very significant and should be taken into account in the ship hull design. This is especially important for ships with a wider bow part such as container ships. Ship response to waves is a very complex hydrodynamic problem, and experimental trials to assess the seakeeping characteristics are very expensive and complicated. Much simpler and cheaper method is to use a variety of software packages. Most important definitions and equations for describing ship motions are given in this paper. The analysis of heave and pitch motions in time history domain is obtained in software packages WISDAM-X and HydroSTAR. The analysis is obtained for four different wavelengths where three were obtained for design speed and one was obtained for the speed greater then design speed. All analyses were made for regular head waves. Comparison was made for the heave and pitch motions calculated in the two software packages in the time history domain to give an insight into the differences between potential and viscous theory in determining the ship motions. To determine the accuracy of the two methods, heave and pitch motions calculated by numerical methods were compared with experimental data and the comparison gave satisfactory results. Sea state in which the ship operates is described with wave and ship response spectra. During the ship design phase it is necessary to ensure that the frequencies at which the ship response spectra and the transfer function reach maximum values are not the same frequencies to avoid resonance. The spectra of the waves and the response spectra are not time dependent but are frequency dependent so the heave and pitch motions are shown in frequency domain as well. Heave and pitch motions in frequency domain for model 1 and model 2 are calculated in the software package HydroSTAR and are compared in graphs. The maximum amplitude of the ship response occurs at different frequencies depending on the length of the model and the ship, so it can be concluded that the area of resonance depends on the main dimensions of the ship.

Item Type:	Thesis (Master's thesis (Bologna))
Uncontrolled Keywords:	potencijalno strujanje; viskozno strujanje; odziv broda na valovima; prijenosna funkcija; Navier-Stokesove jednadžbe
Subjects:	TECHNICAL SCIENCE > Shipbuilding
Divisions:	600 Department of Naval Engineering and Marine Technology > 610 Chair of Hydromechanics of Marine Structures
Date Deposited:	14 Jul 2015 10:18
Last Modified:	16 Oct 2015 12:41
URI:	http://repozitorij.fsb.hr/id/eprint/4632

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