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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Society of Naval Architects of Korea
Journal Basic Information
Journal DOI :
The Society of Naval Architects of Korea
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Volume & Issues
Volume 49, Issue 6 - Dec 2012
Volume 49, Issue 5 - Oct 2012
Volume 49, Issue 4 - Aug 2012
Volume 49, Issue 3 - Jun 2012
Volume 49, Issue 2 - Apr 2012
Volume 49, Issue 1 - Feb 2012
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A Study on the Resistance Reduction of G/T 190ton Class Main Vessel in Korean Large Purse Seiner Fishing System
Park, Ae-Seon ; Lee, Young-Gill ; Kim, Doo-Dong ; Yu, Jin-Won ; Ha, Yoon-Jin ; Jin, Song-Han ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 367~375
DOI : 10.3744/SNAK.2012.49.5.367
In this study, hull form of main vessel of Korean large purse seiner fishing industry is developed for the improvement of resistance performance as well as for the satisfaction to the Standard of Fishing Convention, ILO. Through the modification of reference hull form parameters and local characteristics, the hull form development is carried out. The optimum hull form parameters are searched by Sequential Quadratic Programing(SQP) method with the power estimation method of Holtrop & Mannen. To minimize the wave resistance, bulbous bow parameters are determined by the bulbous bow design method of Alvarino. The plasmatic curve is redesigned from that of the reference hull by using Lackenby method. The resistance performances of the reference and designed hull forms are estimated by using numerical simulation method. Also, the judgment of seakeeping ability and the estimation of intact stability for the designed hull form is carried out. As a result, the optimum hull form is proposed. To verify the improvement of resistance performance, model tests are carried out in towing tank. The results show that the resistance of the designed hull form is about 14% smaller than that of the reference hull from at design speed. A new hull form proposed in this study can contribute to the development of the main vessel hull form of Korean large purse seiner fishing system.
Improvement of Submarine Cooling System using HILS Simulation
Jung, Sung-Young ; Oh, Jin-Seok ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 376~383
DOI : 10.3744/SNAK.2012.49.5.376
Owing to rapid development of power device and inverters, most of submarines adopt an eletric propulsion system. Although PMPM(Permanent Magnet Propulsion Motor) propulsion system has relatively higher power, energy conversion efficiency and smaller volume than engine propulsion system, it also produces large amount of heat due to current flowing inside motor coils and change of magnetic field induced by iron core. The produced heat in stator and inverter largely affects motor efficiency and bearing lubrication and causes thermal aging while the system is on operation. So, we analyze the existing cooling system and submarine ESS (Energy Saving System) cooling system whose power consumption is reduced. HILS(Hardware In the Loop System) technique is used for the modelling of the submarine cooling system. To confirm the ESS cooling system characteristic, HILS is simulated using LabVIEW with hardware. As a result, the ESS cooling system has the characteristic of better temperature stability and less power consumption than the existing one.
Development of Noise Analysis Program by using Power Flow Analysis in Medium-to-high Frequency Ranges
Kwon, Hyun-Wung ; Song, Jee-Hun ; Hong, Suk-Yoon ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 384~390
DOI : 10.3744/SNAK.2012.49.5.384
Power Flow Analysis (PFA) is introduced for solving the noise and vibration analysis of structures in medium-to-high frequency ranges. The vibration analysis software,
R4 based on Power Flow Finite Element Method (PFFEM) and the noise prediction software,
R1 based on Power Flow Boundary Element Method (PFBEM) are developed. In this paper, the coupling equation which represents relation between structural energy and acoustic energy is developed for vibro-acoustic coupling analysis. And vibro-acoustic coupling analysis software based on PFA and coupling equation is developed. Developed software is composed of translator, cavity-finder, solver and post-processor over all. Translator can translate FE model into PFADS FE model and cavity-finder can automatically make NASPFA BE model from PFADS FE model for noise analysis. The solver module calculates the structural energy density, intensity of structures, the fictitious source on the boundary and the acoustic energy density at the field in acoustic cavities. Some applications of vibro-acoustic coupling analysis software to various structures and cruise ship are shown with reliable results.
A Study on the Hull Form Design of a G/T 199ton Class Fishing Boat for Both Fish-luring Lighting and Fish Carrying in Korean Large Purse Seiner Fishing System
Park, Ae-Seon ; Lee, Young-Gill ; Jin, Song-Han ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 391~399
DOI : 10.3744/SNAK.2012.49.5.391
This paper presents a method of hull form design for the assistant vessel which is used both as a lighting boat and a fish carrying boat for the fleet of newly formated purse seiner vessels. The optimum hull form parameters are searched by the Sequential Quadratic Programing(SQP) method with the power estimation method of Van Oortmerssen. The prismatic curve is redesigned from that of the reference hull by the Lackenby method. Through the modification of the hull form by using a CAD system, the design procedure is completed. The resistance performances of the reference and the modified hull forms are estimated by using a numerical simulation method. Also, the estimation of seakeeping ability and stability for the modified hull forms are carried out. And then, an optimum hull form is proposed for the designed hull form. Ship model tests for the reference and the designed hull forms are carried out at ship model basin. The results of the experiments show that the effective horse power of the designed hull form is about 22% smaller than that of the reference hull form at design speed. The designed hull form proposed in this study will contribute to the development of the hull form for Korean large purse seiner vessels.
Development of a Motion Simulator for Portable Type Welding Robot Based on Adaptive Control
Ku, Nam-Kug ; Ha, Sol ; Roh, Myung-Il ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 400~409
DOI : 10.3744/SNAK.2012.49.5.400
It is not easy to know the accurate mass and mass moment of inertia of robot. Because of this uncertainty, error may exist when we control the robot based on the inaccurate mass information. Moreover the properties of the portable robot can change during its operation. Therefore we developed the motion simulator based on the adaptive control. First, the computed torque control was carried out in order to minimize an error between target angles and real angles. The computed torque control is based on the equation of robot motion, which is derived from the Lagrange-Euler equation. To minimize the error between the real model and the approximated model, the adaptive control was carried out. During this simulation, the interference check was also carried out. The interference check verifies that the robot can move successfully without any collision.
PIV Analysis of Flow around a Submerged Pitch Damping Foil
Gim, Ok-Sok ; Lee, Gyoung-Woo ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 410~415
DOI : 10.3744/SNAK.2012.49.5.410
An experimental study is carried out to investigate the near-wake characteristics of a NACA 0018 foil with a flat plate. Two-frame grey-level cross correlation PIV method is used to measure the local flow characteristic around a pitch damping foil to control the vertical motion of high speed crafts in a circulating water channel. The analysis also includes angles of attack 10 and 20 degrees respectively. Reynolds number
based on the chord length(C=100mm) of NACA0018 has been applied during the whole experiments. The distance between the foil and the flat plate is D/C=0.5, 1.0 and 1.5 respectively. The channel effect according as the distance between the foil and the flat plate has a close relation with the velocity distributions around the foil. In the wake of 20-degree of attack, the complex turbulent flow and a thick boundary layer are formed due to the processes of vortex generation and dissipation.
Study on Performance of High Efficiency Series Propeller (KF Series) for Fishing Vessels
Jang, Jin-Yeol ; Kim, Moon-Chan ; Lee, Won-Joon ; Mun, Won-Jun ; Lee, Chang-Sup ; Moon, Il-Sung ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 416~424
DOI : 10.3744/SNAK.2012.49.5.416
The MAU series has been usually used for the fishing vessel's propeller, which has been improved in consideration of the efficiency as well as the cavitation point of view in Pusan National University. The high efficiency standard series propeller(KF series) has been applied to the design of 52ton class fishing vessel's propeller in the previous study. The experimental study for the performance of the design propellers called KF series for 52 ton class fishing vessel has been conducted with five cases in Korea Ocean Research & Development Institute towing tank. The model tests have been carried out at different pitch ratio and expanded area ratio in comparison with the standard propeller to make the series chart. The KF series chart and the formula for performance expression have been completed on the basis of the experiment result.
Numerical Analysis on Hydrodynamic Forces Acting on Side-by-Side Arranged Two-Dimensional Floating Bodies in Viscous Flows
Heo, Jae-Kyung ; Park, Jong-Chun ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 425~432
DOI : 10.3744/SNAK.2012.49.5.425
Viscous flow fields of side-by-side arranged two-dimensional floating bodies are numerically simulated by a Navier-Stokes equation solver. Two identical bodies with a narrow gap are forced to heave and sway motions. Square and rounded bilge hull forms are compared to find out the effects of vortex shedding on damping force. Wave height, force RAOs, added mass and damping coefficients including non-diagonal cross coefficients are calculated and a similarity between the wave height and force RAOs is discussed. CFD which can take into account of viscous damping and vortex shedding shows better results than linear potential theory.
A Study on the Experimental Relation between Parameters for Determining Dry Film Thickness in the Application of Anti Corrosive Paint using Hydraulic Plural Component
Yun, Won-Jun ; Choi, Min-Gu ; Lee, Sung-Goun ; Lee, Yun-Sig ; Heo, Byung-Dong ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 433~439
DOI : 10.3744/SNAK.2012.49.5.433
Anticorrosive paint is the most widely used in shipbuilding and the dry film thickness is very important in terms of productivity and assurance of anticorrosive performance. However, it is difficult to achieve the recommended target film thickness because the dry film thickness depends on labor's skill in practice and is affected by a number of parameters, such as spray pressure, paint flow rate, tip size, spray distance, SVR(Solid Volume Ratio), etc. Present paper derives an empirical equation through the correlation analysis of parameters selected by spray experiments of anti corrosive painting in order to predict the coated status. Comparing the calculated results with practical data, we show that the empirical equation can successfully expect DFT(Dry Film Thickness).
Large Eddy Simulation of Flow around Twisted Offshore Structure with Drag Reduction and Vortex Suppression
Jung, Jae-Hwan ; Yoon, Hyun-Sik ; Choi, Chang-Young ; Chun, Ho-Hwan ; Park, Dong-Woo ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 5, 2012, Pages 440~446
DOI : 10.3744/SNAK.2012.49.5.440
A twisted cylinder has been newly designed by rotating the elliptic cross section along the spanwise direction in order to reduce the drag and vorticies in wake region. The flow around the twisted cylinder at a subcritical Reynolds number (Re) of 3000 is investigated to analyze the effect of twisted spiral pattern on the drag reduction and vortex suppression using large eddy simulation (LES). The instantaneous wake structures of the twisted cylinder are compared with those of a circular and a wavy cylinder at the same Re. The shear layer of the twisted cylinder covering the recirculation region is more elongated than that of the circular and the wavy cylinder. Successively, vortex shedding of the twisted cylinder is considerably suppressed, compared with those of the circular and the wavy cylinder. Consequently, the mean drag coefficient and the fluctuating lift of the twisted cylinder are less than those of the circular and the wavy cylinder.