• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.168-177
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• 2001

Reverse engineering has been widely used for the shape reconstruction of an object without CAD data and the measurement of clay or wood models fur the development of new products. To generate a surface from measured points by a laser scanner, typical steps include the scanning of a clay or wood model, the generation of compatible input curves, the generation of a surface and manufacturing data like G code or STL file. A laser scanner has a great potential to get geometrical data of a model for its frost measuring speed and higher precision. The data from a laser scanner are composed of many line stripes of points including small spikes and noise. A new approach using automated surface generating algorithm is introduced to deal with problems during reverse engineering process. And the input data and the generated surface are represented in IGES format, thus can be supplied to other CAD/CAM software without any data manipulation.

• Bulletin of the Society of Naval Architects of Korea
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• v.7 no.1
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• pp.1-12
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• 1970

The propeller induced pressure fluctuation around a ship's stern is one of the interesting problems from viewpoints of the noise and vibration. Most of the experimental works on the subject employ pressure transducer attached on hull surface near the propeller. In the technique, the measured pressure includes the hydrodynamic pressure transducer attached, if they exit. Hence, the separation of the additional pressure due to vibration from the measured pressure is essential for the determination of true values of the propeller induced pressure. In this paper, to contribute to the separation method, the author investigated the additional hydrodynamic pressure as below, based on the numerical calculation. (1) Hydrodynamic pressure on the body surface of two dimensional cylinders of some mathematical sections such as ellipse, rectangle, Lewis form of hypotrocoidal charactor and curvilinear-element section with chines oscillating vertically at high frequency in a free surface. (2) Hydrodynamic pressure on the surface of the shell plate in local vibration in an ideal fluid.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1382-1388
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• 2014

Proteus vulgaris K80 lipase was expressed in Escherichia coli BL21 (DE3) cells and immobilized on amine-terminated magnetic microparticles (Mag-MPs). The immobilization yield and activity retention were 84.15% and 7.87%, respectively. A homology model of lipase K80 was constructed using P. mirabilis lipase as the template. Many lysine residues were located on the protein surface, remote from active sites. The biochemical characteristics of immobilized lipase K80 were compared with the soluble free form of lipase K80. The optimum temperature of K80-Mag-MPs was $60^{\circ}C$, which was $20^{\circ}C$ higher than that of the soluble form. K80-Mag-MPs also tended to be more stable than the soluble form at elevated temperatures and a broad range of pH. K80-Mag-MP maintained its stable form at up to $40^{\circ}C$ and in a pH range of 5.0-10.0, whereas soluble K80 maintained its activity up to $35^{\circ}C$ and pH 6.0-10.0. K80-Mag-MPs had broader substrate specificity compared with that of soluble K80. K80-Mag-MPs showed about 80% residual relative activity after five recovery trials. These results indicate the potential benefit of K80-Mag-MPs as a biocatalyst in various industries.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.5
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• pp.332-340
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• 2023

The present study established hull form optimization for small catamaran based on variations of knuckle lines. Four knuckle lines below the free surface were employed as design variables. Knuckle lines were independently transformed within remaining the main dimensions of the existing hull. For the hull form optimization, the SHERPA algorithm of HEEDS was utilized. Computational fluid dynamics was employed to estimate the resistance performance. The optimal hull showed the improvement of resistance performance of 9.3% than that of existing hull. The improvement of wave and pressure distributions for optimal hull was confirmed. Throughout the present study, it is expected that established optimization method can be applied for various small vessels such as fishing and leisure boats.

• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.93-101
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• 2013

The incident bore impact loads acting on a tall structure is simulated using the refined Moving Particle Simulation (MPS) method. The particle method is more feasible and effective than conventional grid-based methods for the violent free-surface problems. In the present study, the simulation results for the temporal change of the hydrodynamic force on the structure and longitudinal velocity component around the structure are compared with the experiments (Radd and Bidoae, 2005). And the mitigation effects by installation of various obstacles in front of the main structure are investigated and discussed form the simulation results.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.1-7
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• 2002

A coastwise chemical tanker sailing at full speed has capsized in calm water and while turing. We investigate reasons of the accident and demonstrate that a proper correction for the free surface effect of the liquid cargo has not been practiced in the initial design stage and that the bow-sinkage induced in sailing has weakened the form stability of the ship. It is also shown that the liquid cargo shift occurring in turning generated a significant outward heel moment.

• Bulletin of the Society of Naval Architects of Korea
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• v.5 no.2
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• pp.1-26
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• 1968

This work is a general treatment of added mass calculation of two-dimensional cylinders with straight-framed sections and chines oscillating in the free surface of an ideal fluid with high frequencies. Two and three parameter families in vertical oscillations are treated by employing Schwarz-Christoffel transformation. The results are presented with regards to geometrical parameters such as chine engles, sectional area coefficient and beam draft ratio.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.1
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• pp.67-77
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• 2014

In this study, Explicit Algebraic Reynolds Stress Model (EARSM) which is based on the existing ${\kappa}-{\omega}$ model has been applied to the flow field analysis around ship hulls. Existing transport equations for the turbulent kinetic energy and the dissipation rate are used in almost the same form and anisotropy terms of Reynolds stresses are newly considered. The well-known KVLCC2 and KCS hull forms are selected as validation cases, which were also used in 2010 Workshop on CFD in Ship Hydrodynamics. In case of KVLCC2 double model, comparison of mean velocity distribution, turbulent kinetic energy, and Reynolds stresses near the propeller plane has been carried out and wave elevation and wave profiles have been additionally studied for KCS and KVLCC2 with free surface models. Some improved results for mean velocity distribution at the propeller plane have been obtained while there is little change in free surface wave profiles.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.111-116
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• 1987

The accurate prediction of the ship wave resistance is very important to design ships which operate satisfactorily in a wave environment. Thus, work should continue on development and validation of methods to compute ship wave patterns and wave resistance. Research efforts to improve the prediction of ship waves and wavemaking resistance are categorized in two major areas. First is the development of higher-order theories to take account of the nonlinear effect of the free surface condition and improved analytical treatment of the body boundary condition. Second is the development of direct numerical methods aimed at solving body and free-surface boundary conditions as accurately as possible. A new formulation of the slender body theory for a ship with constant speed is developed by Maruo. It is quite different from the existing slender ship theory by Vossers, Maruo and Tuck. It may be regarded as a substitute for the Neumann-Kelvin approximation. In present work, the method of asymptotic expansion of the Kelvin source is applied to obtain a new wave resistance formulation in fluid of finite depth. It takes a simple form than existing theory.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.407-415
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• 1993

This report presents an automatic measurement method of 3-dimensional profiles of free-formed surfaces, by using a touch a touch-trigger contact probe along with a conventional coordinate measuring machine. The method proceeds in three steps; The surface profile under consideration is traced by the probe in an automatic manner, and then its measured data is compensated by considering the actual probe radius. Finally the compensated data is rearranged in the form suitable for the further processings of CAD/CAM applications. Some experimental results are discussed to verify the validity of the method suggested in this study.