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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 48, Issue 6 - Dec 2011
Volume 48, Issue 5 - Oct 2011
Volume 48, Issue 4 - Aug 2011
Volume 48, Issue 3 - Jun 2011
Volume 48, Issue 2 - Apr 2011
Volume 48, Issue 1 - Feb 2011
Selecting the target year
An Experimental Study on Noise Characteristics of Propeller Cavitation Inception
Lee, Phil-Ho ; Ahn, Byoung-Kwon ; Lee, Chang-Sup ; Lee, Jung-Hoon ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 1~7
DOI : 10.3744/SNAK.2011.48.1.1
Cavitation is the formation of vapour bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapor pressure. Various types of cavitations are generated on the propeller blades. As cavity bubbles passing the blade are forced to oscillate in size or shape and come to collapse, they cause very strong local acoustic waves in the fluid and radiate noise. Comparing the Sound Pressure Level(SPL) before and after cavitation, SPL increases 2dB per 1 knot increase in ship speed above the cavitation inception speed(CIS). Consequently, the CIS is an important criteria to design silent propellers. In this work, experimental measurements of radiated noise according to various types of cavitations from the model propeller are carried out in a large cavitation tunnel and their acoustical characteristics are extensively investigated.
Identification of Four-DOF Dynamics of a RIB using Sea Trial Tests (I) - Sea Trial Test, Resistance and Propulsion Model
Yoon, Hyeon-Kyu ; Yun, Kun-Hang ; Park, In-Hong ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 8~14
DOI : 10.3744/SNAK.2011.48.1.8
RIB(Rigid Inflatable Boat) is widely used for coastal transportation in the commercial use and for ISR(Intelligence, Surveillance, Reconnaissance) in the military use. Since RIB is around 10 meters in length and over 30 knots in speed, its motion characteristics in waves is quite different from a large scale ship. When it turns, large roll occurs and heeling direction is opposite to the large ship's case. Currently, many countries are developing USV(Unmanned Surface Vehicle) of which type is RIB. In order to develop high performance autopilot and way point controller, it is very important to identify RIB's motion characteristics. In this paper, sea trial test results of a 7-meter RIB such as speed, turning, zig-zag, and way point control tests were represented and its resistance and propulsion model was identified by using sea trial data and Savitsky's formula. In addition, the state space model which will be used in the identification of the four-degree-of-freedom dynamics in the next step was formulated and the identification procedure was proposed.
Comparison of Cavitation Patterns between Model Scale Observations using Model and Full-Scale Wakes and Full Scale Observations for a Propeller of Crude Oil Carrier
Choi, Gil-Hwan ; Chang, Bong-Jun ; Hur, Jae-Wook ; Cho, Dae-Seung ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 15~22
DOI : 10.3744/SNAK.2011.48.15
In this paper, cavitation patterns of model tests were compared with those of full-scale measurement for a propeller of crude oil carrier which was suffered from erosions on suction side of blade tip region. Cavitation tests were performed at design and ballast draft using model and full scale nominal wakes. A model ship and wire mesh method was used for the simulation of wake patterns of model nominal wakes. For the prediction of full-scale wake patterns, a RANS solver(Fluent 6.3) was used and wire mesh method was used for the simulation of the full scale wakes. Comparison results show that cavitation patterns using predicted full-scale wake patterns are closer to cavitation patterns of full-scale measurement at ballast draft condition. Also, cloud cavitations were observed on the position of eroded area at both full-scale measurement and cavitation tests using simulated full-scale wake patterns.
Numerical Analysis of Hydrodynamic Performance of a Movable Submerged Breakwater
Koo, Weon-Cheol ; Kim, Do-Hyun ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 23~32
DOI : 10.3744/SNAK.2011.48.1.23
Numerical analysis of hydrodynamic performance of a movable submerged breakwater was carried out as an eco-friendly marine structure for coastal and harbor protection. Using boundary elements method with two-dimensional frequency-domain reflection and transmission coefficients and wave forces acting on the submerged flat plate were calculated with various submerged depths and respective motion allowable modes. The movable breakwater was found to be more efficient in wave-blocking than the fixed structure. Variation of reflection coefficients was significantly influenced by vertical motion of the body.
Damage Estimation of Large-Sized Vessels due to Ship-to-Ship Collisions and Ship Groundings
Choung, Joon-Mo ; Lee, Min-Seong ; Nam, Ji-Myung ; Ha, Tae-Bum ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 33~41
DOI : 10.3744/SNAK.2011.48.1.33
For the assessment of ultimate longitudinal strengths of damaged hull girders, it is preliminarily necessary to determine the extents and locations of the damages due to severe accidents. This paper deals with the estimation of the damages from collisions and groundings of large-sized vessels where deterministic and probabilistic approaches are investigated. Deterministic damages estimated from MARPOL(or ICLL), ABS and DNV are compared with probabilistic damages from IMO guideline and some references including damage statistic data. Damages from MARPOL show largest one among all the investigated damage estimation, since it was developed not for the residual strength of hull girder but for the damage stability calculation. IMO guideline with high level probability of damage(eg. 95% probability level) also forecasts even severer damage extents than MARPOL. On the other hand, assuming average probability level of damage, the calculated damage sizes are around the one from deterministic approaches.
Comparative Study on Material Constitutive Models of Ice
Choung, Joon-Mo ; Nam, Ji-Myung ; Kim, Kyung-Su ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 42~48
DOI : 10.3744/SNAK.2011.48.1.42
To define ice as a solid material, mathematical and physical characteristics and their application examples are investigated for several materials' yield functions which include isotropic elastic, isotropic elastic-plastic, classical Drucker-Prager, Drucker-Prager Cap, Heinonen's elliptic, Derradji-Aouat's elliptic, and crushable foam models. Taking into account brittle failure mode of ice subject to high loading rate or extremely low temperature, isotropic elastic model can be better practicable than isotropic elastic-plastic model. If a failure criterion can be properly determined, the elastic model will provide relatively practicable impact force history from ice-hull interactions. On the other hand, it is thought that the soil models can better predict the ice spalling mechanism, since they contain both terms of shear stress-induced and hydrostatic stress-induced failures in the yield function.
Evaluation of Sound Insulation Performance of a Unit Cabin Mock-up
Kim, Hyun-Sil ; Kim, Sang-Ryul ; Kim, Bong-Ki ; Kim, Jae-Seung ; Lee, Sung-Hyun ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 49~55
DOI : 10.3744/SNAK.2011.48.1.49
Sound insulation performance of a unit cabin mock-up is studied, where two identical rooms simulating cruise ship cabin are installed. STL (Sound Transmission Loss) measurement in the mock-up shows that STL of the partition between rooms is degraded by imperfect door ceiling and gap between wall and floor. It is also observed that gap around lighting and electrical outlet slightly affect the STL in high frequency ranges, since lighting and electrical outlet are supported by mineral wool in the back side due to fire-resistance requirement. Even after all possible gaps are sealed, STL of the partition is found to be lower than that measured in the laboratory by 9 dB. Measurement of SBN (Structure-Borne Noise) reveals that flanking transmission of SBN along the steel deck floor can severely deteriorate STL of the partition. Statistical energy analysis (SEA) of the mock-up confirms importance of the floor SBN control, in which increasing damping is essential to ensure high STL.
Fatigue Assessment of High Strength Steel with Butt Welded Joints for the Root Gap Difference
Kim, Ho-Jung ; Kang, Sung-Won ; Kim, Myung-Hyun ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 56~61
DOI : 10.3744/SNAK.2011.48.1.56
In this study, a series of fatigue tests was conducted to evaluate fatigue strength for the root gap difference with high strength steel with butt welded joints. A finite element analysis using effective notch stress method was also performed to compare effective notch factors each other with butt welded specimens made by copper backing. The results of fatigue tests were classified according to the root gap difference. Fatigue life of butt welded specimens is presented for determining the root gap of high strength steel with butt welded joints in terms of fatigue strength. Then effective notch stress was applied to interpret fatigue strength of butt welded specimen model which is reflected actual measured dimensions. As a result, fatigue strength of high strength steel with butt welded specimens is increased by root gap gets longer in length.
The Study for Evaluation of Thermal Comfort in Passenger Cabin on Cruise Ship
Koo, Keun-Hae ; Lee, Ho-Ki ; Choi, Jae-Woong ; Lee, Jae-Keun ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 62~66
DOI : 10.3744/SNAK.2011.48.1.62
The present work focuses on the evaluation of thermal comfort in passenger cabin of a cruise ship. A computational fluid dynamics (CFD(Airpak)) is used to calculate air velocity and temperature distribution in the passenger cabin as well as PMV and PPD. The CFD is used to simulate two different cases, room unit system and wardrobe duct system. Both of cases are simulated in summer environment condition. The room unit system and wardrobe duct system are compared and evaluated by ISO 7730 thermal comfort categories. The performance of room unit system is shown to be more effective for this typical case of passenger cabin.
The Naval Architectural Examination on "Pyomindaehwa" (Presumption of the Type of Drifting Ship)
Park, Gen-Ong ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 67~75
DOI : 10.3744/SNAK.2011.48.1.67
Pyomindaehwa is a study book written in Korean and it takes a form of an investigation document made up of a conversation between Chosen's castaways and an interpreter taking place in Naesirogawa and Satsuma on the south end of Kyushu, Japan in the 19th century. This book is in three volumes. Many terminologies such as timber parts, sail, rigging and equipment have been shown in the last volume, which is mainly about a repairing process of drifting ship. Especially, timber parts' terminologies including hull's term were schematized in Kumamoto Text(1854b). This study have attempted to find out Naval architectural clues helping estimate actual drifting ship's type and bulk on the evidence of the contents. Based on the studies, it is possible to presume the type of Korean boats and ships, which are similar with the ones from database of 21 traditional fishing boats in the report on Investigation of Korean fishing boats studied previously. This paper has shown the logical process of presumption of types of boats.
A Study of Optimum Shielding Gas Flow Rate in FCAW for Shipbuilding
Lee, Hoon-Dong ; Shim, Chun-Sik ; Song, Ha-Cheol ; Yum, Jae-Seon ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 76~83
DOI : 10.3744/SNAK.2011.48.1.76
FCAW(Flux Cored Arc Welding) is a widely used welding method in shipbuilding. It also conducts WPS(Welding Procedure Specification) requested by the classification variations of the factors which affect the quality on the welded area such as thickness of base metal, type of welding wire and shielding gas etc. which has to be satisfied. CO2 is commonly used as a shielding gas for FCAW due to the economic point of view. The amount of shielding gas is stated when classification certify WPS. However, the shielding gas is unnecessarily used at the shipyard leaning only on the welder's experience as there are classification standards for using the shielding gas. It causes production cost to rise. Also recently, CO2 is a main contributor for global warming, and large amounts of CO2 are discharged into the atmosphere during shipbuilding processes without any filtration. Therefore it was confirmed by the security of the welded area as a result of conducting the destructive and non-destructive tests with setting up the factors and the standards by using the Taguchi method. Then the FCAW shielding gas's amounts were calculated precisely when assembling a ship. It will be applied to cost reduction and prevention of environmental pollution at the shipyard.
Conceptual Design of SMART HARBOR
Shin, Hyun-Kyoung ; Kim, Min-Su ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 84~92
DOI : 10.3744/SNAK.2011.48.1.84
This paper presents the primary conceptual design results of Smart Harbor. As the world trade becomes active, so container cargo volume is increasing constantly. Since the coming of very large container ships, It's necessary that a harbor handles many containers more than before. Therefore, we designed the new concept of SMART HARBOR which overcomes land site problem for port expansion and geographic constraints of very large container ships in harbor.
A Study on Anti-Icing Technique for Ballast Water of Icebreaking Vessels Operating in Ice-Covered Water
Jeong, Seong-Yeob ; Lee, Chun-Ju ; Cho, Seong-Rak ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 1, 2011, Pages 93~97
DOI : 10.3744/SNAK.2011.48.1.93
When freezing is present on ballast water, it can impose additional loads on the hull and effect on stabilization of ship. The anti-icing techniques of ballast water, therefore, are key criteria for ship safety. The existing anti-icing techniques of ballast tank are hull heating, water circulation and air bubble system etc. In this research, anti-icing performance tests for the ballast water using micro-bubble system and sea water circulation system have been carried out at two temperature conditions(
). Ambient temperature, sea water temperature and temperature of the inner parts of the ballast tank are measured and also ballast water conditions are checked during the model test. The applied anti-icing techniques of ballast water, such as micro-bubble system and sea water circulation system show good performance in the low temperature conditions.