• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.134-140
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• 2011

The present paper deals with characteristics of resistance performance according to the variation of synthetic ice thickness and hull form. The resistance test has been conducted with pack ice condition in Pusan National University towing tank. Waterline angle has been chosen as a main parameter for the variation of hull form characteristics, which is the most important factor especially in icebreaking cargo vessel. The serial comparisons of resistance test have been done with the variation of hull form parameter as well as with the different thickness of synthetic ice. The different trend of resistance performances with increasing of waterline angle has been shown at each synthetic ice thickness. The present test results is expected to be confirmed by comparing the test results in ice tank in the near future.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.876-893
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• 2014

The resistance performance of an icebreaking cargo vessel according to the variation of waterline angles is investigated numerically and experimentally. A recently developed Finite Element (FE) model is used in our analysis. A resistance test with synthetic ice is performed in the towing tank at Pusan National University (PNU) to compare and validate the computed results. We demonstrate good agreement between the experimental and numerical results. Shipice interaction loads are numerically calculated based on the Fluid Structure Interaction (FSI) method in the commercial FE package LS-DYNA. Test results from model testing with synthetic ice at the PNU towing tank are used to compare and validate the numerical simulations. For each waterline angle, numerical and experimental comparisons were made for three concentrations (90%, 80%, and 60%) of pack ice. Ice was modeled as a rigid body, but the ice density was the same as that used in the experiments. A comparative study according to the variation of stem angles is expected to be conducted in the near future.

• Journal of the Korean Institute of Navigation
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• v.15 no.3
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• pp.73-97
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• 1991

The analysis and investigation are described for White's[2] equations compared to the equations of Runeburg[3] and Milano[5] for continuous icebreaking mode, Tunik[8-1] and Ghoneim[8-2] for ramming icebreaking mode. Calculation results compare reasonably well with published model-scale and full-scale icebreaker data by Baker[1] and Dick[11]. During continuous and ramming mode operation, using characteristics of an incebreaker, down ward force on ice and standard ice thickness broken are predicted. Additionally draft, trim and extraction difficulty are also predicted. The bow part line of an icebreakin $g^{ply}$ vessel is designed aiming to maximize the ice breaking capabiltiy as following conditions-low bow angle[20 degrees] at designed waterline, small spread angle complement [6 degrees] at designed waterline, small spread angle complement [6 degrees] and high propeller thrust [220tons]. with plow, two reamers and wave type bumper.

• Korean Journal of Remote Sensing
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• v.25 no.4
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• pp.383-389
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• 2009

The main objective of the research is a feasibility study on the intertidal zone using a X-band radar satellite, TerraSAR-X. The TerraSAR-X data have been acquired in the west coast of Korea where large tidal flats, Ganghwa and Yeongjong tidal flats, are developed. Investigations include: 1) waterline and backscattering characteristics of the high resolution X-band images in tidal flats; 2) polarimetric signature of halophytes (or salt marsh plants), specifically Suaeda japonica; and 3) phase and coherence of interferometric pairs. Waterlines from TerraSAR-X data satisfy the requirement of horizontal accuracy of 60 m that corresponds to 20 cm in average height difference while current other spaceborne SAR systems could not meet the requirement. HH-polarization was the best for extraction of waterline, and its geometric position is reliable due to the short wavelength and accurate orbit control of the TerraSAR-X. A halophyte or salt marsh plant, Suaeda japonica, is an indicator of local sea level change. From X-band ground radar measurements, a dual polarization of VV/VH-pol. is anticipated to be the best for detection of the plant with about 9 dB difference at 35 degree incidence angle. However, TerraSAR-X HH/TV dual polarization was turned to be more effective for salt marsh monitoring. The HH-HV value was the maximum of about 7.9 dB at 31.6 degree incidence angle, which is fairly consistent with the results of X-band ground radar measurement. The boundary of salt marsh is effectively traceable specifically by TerraSAR-X cross-polarization data. While interferometric phase is not coherent within normal tidal flat, areas of salt marsh where the landization is preceded show coherent interferometric phases regardless of seasons or tide conditions. Although TerraSAR-X interferometry may not be effective to directly measure height or changes in tidal flat surface, TanDEM-X or other future X-band SAR tandem missions within one-day interval would be useful for mapping tidal flat topography.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.99-106
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• 2011

The appearance of CSR changes the concept of the hull form design as well as structural design, since the application of CSR inevitably brings the lightweight increase of a ship. Keeping the original design constraints such as principal particulars, deadweight, and speed performance, designers have to increase the volume of the hull form. As a result, the entrance angle at bow end should become larger, which results in blunter waterline shape. For a slow and full ship having high $C_B$ more than 0.85, a new concept of bow shape has been required to alleviate the increase of wave-making resistance, since it is very difficult to improve waterline and frameline shape for such a full ship. In this paper a new bow shape of Capesize Bulk Carrier was developed to improve its wave-making characteristics without incompliance with the design constraints. For loading manual calculation, NAPA software was used. FLUENT6.3.26 and WAVIS1.4 were used to evaluate resistance performance of the subject hull forms. The newly designed hull form was tested at SSPA model basin for the final confirmation of resistance and propulsion performance of the ship. It was found that the new bow shape of a Capesize Bulk Carrier improved the resistance characteristics greatly compared to a conventional bulbous bow. The other benefits of new bow shape on the manufacturability were also investigated.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.5
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• pp.471-478
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• 2009

The present paper deals with characteristics of resistance performance according to the variation of synthetic ice thickness and hull form. The resistance test has been conducted with pack ice condition in Pusan National University towing tank. Stem angle has been chosen as main parameters for the variation of hull form characteristics, which is the most important factor especially in icebreaking cargo vessel. The serial comparisons of resistance test have been done with the variation of hull form parameter as well as with the different thickness of synthetic ice. The different trend of resistance performances with increasing of stem angle has been shown at each synthetic ice thickness. The present test results is expected to be confirmed by comparing the test results in ice tank in the near future.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.120-125
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• 2004

There are very few numbers of 115K FPP (Fixed Pitch Propulsion) Tankers for the Baltic ice class IA because the minimum power requirement of FMA (Finish- Swedish Maritime Association) needs quite large engine power and the 40 m Beam is out of calculation range of FMA minimum power requirements. The shipyard has no choice except to increase the engine power to satisfy FMA minimum power requirement Rule. And the operation cost, efficiency of hullform and its building cost are not good from the ship owners' point of view To solve this problem, the experience of ice breaking tanker development and the ice tank test results were adopted. The main idea to reduce the ice resistance is by reducing waterline angle at design load waterline. The reason behind the main idea is to reduce the ice-clearing force. Two hull forms were developed to satisfy Baltic Ice class IA. Two ice tank tests and one towing tank test was performed at MARC (Kvaener-Masa Arctic Research Center) and SSMB (Samsung Ship Model Basin) facilities, respectively. The purpose of these tests was to verify the performance in ice and open water respectively The hull form 2 shows less speed loss compared to Hull form 1 in open water operation but hull form 2 shows very good ice clearing ability. finally the Hull Form 2 satisfying Baltic ice class IA. The merit of this hull form is to use the same engine capacity and no major design changes in hull form and other related designs But the hull structure has to be changed according to the ice class grade. The difference in two hull form development methods, ice model test methods and analysis methods of ice model test will be described in this paper.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.246-252
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• 2016

In this study, conceptual design of the fore-body hull form of catamaran type dredging vessel was performed that can effectively remove the contaminated sediments in coastal seabed. The hull form was simpled for the easy hull construction and the resistance performance was investigated to find out the effect of hull form parameters between variation of waterline and angle of entrance, etc. The relation between resistance performance and characteristics of free surface flows according to variation of bow forms was investigated by model testing in the circulating water channel and using Ansys CFX. The improvement of ship resistance performance to the wave resistance decrease due to improved wave pattern has been verified according to move the stem and the volume of the shoulder to the fore part of the vessel.