Barge Stern Optimization Analysis on a straight shaped stern using CFD
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Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Publicerad
2011
Författare
Eliasson, Sofia
Olsson, Daniel
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
A barge is a vessel which is designed to transport very heavy loads. Barge sterns therefore have steep inclination angles which will yield a large displacement and hence maximize the cargo capacity. In this thesis the barge stern of the split hopper barge D14 design made by Fartygskonstruktioner AB has been analysed using SHIPFLOW, a CFD software. It is of interest to investigate how the inclination angle affects the resistance of the barge. Since this analysis will focus on the stern, the flow right behind the hull is of importance. Considering that, a zonal approach was chosen for the CFD computations. This approach uses viscous flow computations (or RANS computations) to solve the wake flow at the stern. Two different conditions of the barge have been analysed, a fully loaded condition and a ballast condition. When the barge is fully loaded there is no trim while at ballast condition there is a large trim. As a first step in the analysis computations were run on the initial hull design and the results where then verified with existing results from a resistance test made on a model of the full scale barge. When accurate results had been achieved for the initial stern the analysis continued with computations run on modified sterns where the inclination angle was systematically changed. Unfortunately the analysis could not be completed for ballast condition since a bug in SHIPFLOW was revealed and it turned out that largely trimmed conditions could not be handled by the software. For the analysis of modified sterns, computations were run on two sterns with a steeper inclination than for the initial stern and two sterns with lesser inclination. The outcome of the computations was that in the speed interval from 9 to 12 knots the initial hull has the lowest total resistance when comparing to the modified sterns, but at speeds lower than 9 knots the steepest inclination resulted in the lowest total resistance.
Beskrivning
Ämne/nyckelord
Transport , Farkostteknik , Transport , Vehicle Engineering