• 한국기계연구소 소보
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• s.12
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• pp.63-71
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• 1984

A new kind of bulb called Stern-End-Bulb(SEB) for the improvement of the after part of fine hull forms was developed. The reduction of wave resistance and the improvement of the powering performance for the ship with SEB were shown by the ship model tests, At the same time, the characteristics of wave in the vicinity of the stern and the mechanism of the resistance reduction by SEB were investigated. By the systematical variation of the SEB size, the optimum size of SEB was obtained.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.167-172
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• 1986

This experiment was carried out to obtain some information about the growth habit and morphological and anatomical characteristics of fasciated soybean, var. Buchai-kong. The results obtained are summarized as follows: 1. Main stern of fasciated soybean, var. Buchai-kong was gradually broadened and became flat, on which leaves emerged irregularly compared with normal soybean, var. Danyeop-kong. The number of leaves on main stern was more in Buchai-kong, but the total number of leaves per plant was not considerably different each other. 2. The degree of fasciation (max./min. in diameter at the broadened part) in main stern of Buchai-kong was about 3.1, and was related to the amount of growth of main stern and branches of Danyeop-kong. Stern fasciation types found in Buchai-kong were linear (the most common) and bifurcated with regard to branching of main stern tip. 3. The number of branches per plant was much less in Buchai-kong than in Danyeop-kong. There were fas-ciated branches and fasciated petiole in Buchai-kong. 4. About 75 percent of pods of Buchai-kong were concentrated on the top of stern, which showed strong pod clustering. 5. Seed yield per plant of Buchai-kong was about 60 percent of that of Danyeop-kong, and the decrease in seed yield was mostly affected by the decrease in seed weight and seeds per pod. 6. The number of vascular bundles of transection of mature stern was more in Buchai-kong, but Danyeop-kong developed the better vascular bundle.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.2
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• pp.90-96
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• 1996

This paper presents a method that determines the stern profile dimensions for full, slwo-speed ship using fuzzy modeling, which is applied the genetic algorithm and the Hooke & Jeeves method. The infreed stern profile dimensions have compared with real ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.6 no.1
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• pp.35-45
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• 2000

The slipway, which is one of stern construction, is necessary for stern trawler to let fishing implements, such as fishing net, otter board and warp, go out effectively. It may be doubtable whether there is any possibility for deckwetness to occur because the slipway is obliquely in contact with sea surface. The author discusses any possibility for deckwetness through slipway of stern trawler in wind and waves. A 350 G/T class, ocean-going stern trawler is adopted for the present study. The stem trawler is particularly assumed to drift with fishing implements hung down the slipway due to internal or external accident during fishing operation in real sea. The author considers two factors as possibility for deckwetness to occur through slipway. One is mooring effect of fishing implements hung down the slipway under wind pressure, and the other is relative ship motion in vertical direction in waves. Through the numerical calculation, the author clarifies that there is thin possibility for deckwetness to occur from above two points of view.

• Journal of Mechanical Science and Technology
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• v.14 no.4
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• pp.448-455
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• 2000

The bow wave breaking and the viscous interaction of stern wave are studied by simulating the free-surface flows. The Navier-Stokes equation is solved by a finite difference method in which the body-fitted coordinate system, the wall function and the triple-grid system are invoked. After validation, the calculations are extended to turbulent flows. The wave elevation at the Reynolds number of $10^4$ is much less than that at $10^6$ although the Froude number is the same. The numerical appearance of the sub-breaking waves is qualitatively supported by experimental observation. They are also applied to study the stern flow of S-103 for which extensive experimental data are available. Although the interaction between separation and the stern wave generation are not yet clear, the effects of the bow wave on the development of the boundary layer flows are concluded to be significant.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.134-137
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• 2005

Recently, in VLCC, shafting system is stiffer due to large engine power whereas hull structure is more flexible due to scantling optimization, which can be suffered from alignment damage by incompatibility between shafting and hull, In this study, shafting system without stern tube forward bush was adapted for less sensitive system against external factors. Also, shaft alignment analysis was considered with hull deflection at various ship loading conditions and stern tube after bush of long journal bearing was evaluated by static squeezing pressure and dynamic oil film pressure with sloping control. Whirling vibration was also reviewed to avoid resonance with propeller blade order. So, reliable shafting design for VLCC could be achieved through optimized alignment analysis for the system without stern tube forward bush.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.6
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• pp.564-571
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• 2007

In the present study, stern form optimization has been carried out using computational fluid dynamics (CFD) techniques. The viscous pressure drag has been minimized to optimize stern shape. Parametric modification function has been used to modify the shape of the hull. By the use of the parametric modification function and algebraic scheme to grid manipulation, the initial ship geometry was easily deformed according to change of design parameters. For purpose of illustration, KRISO 319K VLCC (KVLCC) is chosen for example ship to demonstrate stern form optimization. The numerical results indicate that the optimized hull yields a reduction in viscous resistance.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.1
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• pp.70-74
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• 2004

Model tests for a stern flap have been performed to decrease the resistance of a large warship and to optimize the flap. Stern flaps and wedges of fast crafts are studied to apply to a large vessel in terms of speed-length ratio. The model tests of the flap has been carried out to find the effects of the design parameters, i.e. length and angie on resistance decrease. This work concludes that the optimized stern flap reduced resistance not only at the high speed by 9％ but also at the cruising speed.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.4
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• pp.361-369
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• 2008

The optimized distance between skegs and angle of the skeg for a standard twin-skeg type LNG carrier were presented using the CFD and model tests. The evaluation method of self-propulsion performance was derived based on the results of CFD and confirmed the validity through model tests. The analyses to assess self-propulsion performance using CFD were shown by flow line patterns on the skeg surface, nominal wake distribution in the propeller plane and the evaluation for flow balance around stern skegs. The optimized ship that was applied to the optimized two design parameters in stern skeg arrangement for target ship was derived in this work. Finally speed performance of mother ship which is existing ship and optimized ship were compared through CFD and model tests. And the usefulness about the evaluation method of self-propulsion performance was reconfirmed.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.1
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• pp.15-22
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• 2004

Twin-skeg type stern shapes are recently adopted for very large commercial ships. However it is difficult to apply a CFD system to a hull form having twin-skeg, since grid topology around a twin-skeg type stern is more complicated than that of a conventional single-screw ship, or of an open-shaft type twin-screw ship with center-skeg. In the present study a surface mesh generator and a multi-block field grid generation program have been developed for twin-skeg type stern. Furthermore, multi-block flow solvers are utilized for potential and viscous flow analysis around a twin-skeg type stern The present computational system is applied to a 15,000TEU container ship with twin-skeg to prove the applicability. Wave profiles and wake distribution are calculated using the developed flow analysis tools and the results are compared with towing tank measurements.