Barge Stern Optimization Analysis on a straight shaped stern using CFD

Sammanfattning: A barge is a vessel which is designed to transport very heavy loads. Barge sternstherefore have steep inclination angles which will yield a large displacement and hencemaximize the cargo capacity. In this thesis the barge stern of the split hopper bargeD14 design made by Fartygskonstruktioner AB has been analysed using SHIPFLOW, aCFD software. It is of interest to investigate how the inclination angle affects theresistance of the barge. Since this analysis will focus on the stern, the flow right behindthe hull is of importance. Considering that, a zonal approach was chosen for the CFDcomputations. 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 anda ballast condition. When the barge is fully loaded there is no trim while at ballastcondition there is a large trim. As a first step in the analysis computations were run onthe initial hull design and the results where then verified with existing results from aresistance test made on a model of the full scale barge. When accurate results hadbeen achieved for the initial stern the analysis continued with computations run onmodified sterns where the inclination angle was systematically changed. Unfortunatelythe analysis could not be completed for ballast condition since a bug in SHIPFLOW wasrevealed and it turned out that largely trimmed conditions could not be handled by thesoftware.For the analysis of modified sterns, computations were run on two sterns with asteeper inclination than for the initial stern and two sterns with lesser inclination. Theoutcome of the computations was that in the speed interval from 9 to 12 knots theinitial hull has the lowest total resistance when comparing to the modified sterns, butat speeds lower than 9 knots the steepest inclination resulted in the lowest totalresistance.