• Bulletin of the Society of Naval Architects of Korea
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• v.16 no.3
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• pp.35-47
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• 1979

Wave resistance of a parabolic thin ship, with its boundary layer and wake taken into account, was calculated up to second order. In addition to the double-model source distribution on the centerplane, image sources of the wave potential were calculated to keep the body introduced boundary condition undisturbed. Boundary layer and wake effects on the wave-making resistance were included by generating an irrotational flow which matches that exterior to the boundary layer and wake. For this purpose, the boundary layer and wake were calculated. The wave resistance refined with second-order corrections are found to be very important for wave resistance calculations even at moderate Froude numbers($Fr=0.2{\sim}0.3$). Wave-potential corrections are dominate around the bow. On the other hand, Viscosity plays and important role at the stern with its boundary layer and wake development.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.256-257
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• 2012

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.25-31
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• 2003

Numerical experiments have been conducted using the nonlinear combined refraction-diffraction model, in order to analyze the generation characteristics of stem wave, which is formed by the interaction between vertical structure and the oblique incident waves. The results of stem wave are discussed through the stem wave height distribution along/normal vertical structure, under the wide range of incident wave conditions-wave heights, periods, depths, and angles. Under the same wave height and period, the larger the incident wave angle, the higher the stem wave heights. According to the results of wave height distribution, in front of vertical structure, the maximum of stern wave heights occurs in the location bordering the vertical wall. Furthermore, the most significant result is that stem waves occur under the incident angles between $0^{\circ}\;and\;30^{\circ}$, and the stem wave height ratio has the maximum value, which is approximately 1.85 times the incident wave height when the incident wave angle becomes $23^{\circ}$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.65-72
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• 2004

This paper deals with an experimental study on the dynamical characteristics of ship motion during trawling job on the real sea. The experiments were carried out on the small stern trawler, and roll and pitch motion of the ship according to the wave directions were simultaneously recorded by P/C in the same sea conditions. From these data, the statistical properties and power spectra were obtained, and then the analysis of ship motion in trwal job was made. As a result, it was found that the pitch motions in trwal job were displayed low amplitudes on the whole, but the rolling motions were displayed high amplitudes relatively, and very high value on the beam and quartering sea especially. Also, the trial ship has a high extinction coefficient in the roll motion, compared with the rule of stability, but when wave height takes 2.5m over, it can induce the safety of ship to scare occasionally. Therefore, a usefull countermeasure for the safety of ship has to be made adequately.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.3 s.153
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• pp.258-266
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• 2007

CFD calculations are performed for KRISO 3600TEU container ship(KCS) models with different Reynolds numbers. Numerical calculations of the turbulent flows with the free surface around KCS have been carried out at $Re=0.791{\times}106\;and\;Re=1.4{\times}107$ using a standard Fluent package. In both cases, Froude number is fixed with 0.26 and wave elevation is simulated by using the VOF method. The calculated results at $Re=1.4{\times}107\;and\;Re=0.791{\times}106$ are compared with the experiment data of KRISO towing tank test and RIMS CWC test, respectively. Boundary layer thickness and wake field shows Reynolds number differences. There are some changes in wave pattern behind transom stern.

• Journal of Navigation and Port Research
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• v.30 no.8 s.114
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• pp.631-636
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• 2006

In this paper, the wave pattern around the hull with the transom stern advancing on the free surface with a constant speed was taken into consideration. To solve the problem the numerical analysis program was developed using Rankine source panel method based on potential flow analysis technique. The non-linearity of the free surface boundary conditions was fully satisfied. To verify the validity of the developed program the numerical calculations for Athena hull and KCS(KRISO container ship) hull was performed. The results of the numerical computation was compared with the ones of the model test experiment.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.226-231
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• 2003

The viscous interaction of stern wave is studied by simulating the free-surface flows, including sub-breaking phenomena around a high speed catamaran hull advancing on calm water. The Navier-Stokes equation is solved by a finite difference method where the body-fitted coordinate system, the wall function and the triple-grid system are invoked. The numerical appearance of the sub-breaking waves is qualitatively supported by the experimental observation They are also applied to study precisely on the stern flow of S-103 as to which extensive experimental data are available. For the catamaran, computations are carried out for the mono ana twin hulls.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.100-114
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• 2015

This paper deploys optimization techniques to obtain the optimum hull form of KSUEZMAX at the conditions of full-load draft and design speed. The processes have been carried out using a RaPID-HOP program. The bow and the stern hull-forms are optimized separately without altering neither, and the resulting versions of the two are then combined. Objective functions are the minimum values of wave-making and viscous pressure resistance coefficients for the bow and stern. Parametric modification functions for the bow hull-form variation are SAC shape, section shape (U-V type, DLWL type), bulb shape (bulb height and size); and those for the stern are SAC and section shape (U-V type, DLWL type). WAVIS version 1.3 code is used for the potential and the viscous-flow solver. Prior to the optimization, a parametric study has been conducted to observe the effects of design parameters on the objective functions. SQP has been applied for the optimization algorithm. The model tests have been conducted at a towing tank to evaluate the resistance performance of the optimized hull-form. It has been noted that the optimized hull-form brings 2.4% and 6.8% reduction in total and residual resistance coefficients compared to those of the original hull-form. The propulsive efficiency increases by 2.0% and the delivered power is reduced 3.7%, whereas the propeller rotating speed increases slightly by 0.41 rpm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.54-60
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• 2006

This study looks over the relation between propeller and noise in ship stern structure. Near field noise and vibration measurements are compared with the analytical results using wave number method. To avoid singularity in wave number integration method, fast field method is introduced. Analytical results show that main transmission mechanism of high frequency noise is structure-borne type and that of low frequency noise is a air-borne type.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.3
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• pp.258-266
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• 2017

Numerical simulations of turbulent two phase flows around KCS have been performed to investigate effects of trim conditions on ship resistance of KCS in short waves by utilizing waves2foam. The wave lengths of LPP/2 and LPP/4 with 1m and 2m wave heights were imposed at inlet boundary. The resistance reduction at 2m trim by head and the increase of resistance at trims by stern were observed regardless of wave lengths and wave heights. The hull pressure on fore-and-aft rather than wave patterns around bulbous bows was mainly responsible for the total resistance coefficients of KCS in short waves. A phase diagram of contribution of hull pressure to the total resistance coefficients disclosed that the phase of representing the maximum resistance in time history played an important role in the effect of trim conditions on ship resistance of KCS in short waves.