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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Society of Naval Architects of Korea
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Journal DOI :
The Society of Naval Architects of Korea
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Volume & Issues
Volume 47, Issue 6 - Dec 2010
Volume 47, Issue 5 - Oct 2010
Volume 47, Issue 4 - Aug 2010
Volume 47, Issue 3 - Jun 2010
Volume 47, Issue 2 - Apr 2010
Volume 47, Issue 1 - Feb 2010
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Numerical Simulation of Free Surface Flow Using a Refined HRIC VOF Method
Park, II-Ryong ; Kim, Kwang-Soo ; Kim, Jin ; Van, Suak-Ho ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 279~290
DOI : 10.3744/SNAK.2010.47.3.279
In this paper, a VOF method called RHRIC (refined high resolution intertace capturing) is introduced for solving the motion of the free surface and applied to the simulation of the advection of rigid interiaces of different shapes and a 20 dam-break problem, which are typical benchmark test cases. The numerical results for the interface advection cases are compared to the analytic solutions, while the available experimental data and other numerical results of various free surface methods for the dam-break problem are provided for the validation of the proposed VOF method. The same simulations were also carried out using the original HRIC scheme and a modified HRIC scheme called MHRIC for comparison. Although the RHRIC uses a simple order scheme, a basis of the original HRIC scheme, lower than the third-order ULTIMATE-QUICKEST used by the MHRIC, it provides an improved accuracy over the two previous HRIC methods.
Estimation of Large Amplitude Motions and Wave Loads of a Ship Advancing in Transient Waves by Using a Three Dimensional Time-domain Approximate Body-exact Nonlinear 2
Hong, Do-Chun ; Hong, Sa-Young ; Sung, Hong-Gun ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 291~305
DOI : 10.3744/SNAK.2010.47.3.291
A three-dimensional time-domain calculation method is of crucial importance in prediction of the motions and wave loads of a ship advancing in a severe irregular sea. The exact solution of the free surface wave-ship interaction problem is very complicated because of the essentially nonlinear boundary conditions. In this paper, an approximate body nonlinear approach based on the three-dimensional time-domain forward-speed free-surface Green function has been presented. The Froude-Krylov force and the hydrostatic restoring force are calculated over the instantaneous wetted surface of the ship while the forces due to the radiation and scattering potentials over the mean wetted surface. The time-domain radiation and scattering potentials have been obtained from a time invariant kernel of integral equations for the potentials which are discretized according to the second-order boundary element method (Hong and Hong 2008). The diffraction impulse-response functions of the Wigley seakeeping model advancing in transient head waves at various Froude numbers have been presented. A simulation of coupled heave-pitch motion of a long rectangular barge advancing in regular head waves of large amplitude has been carried out. Comparisons between the linear and the approximate body nonlinear numerical results of motions and wave loads of the barge at a nonzero Froude number have been made.
Analysis of Linear Springing Responses of a Container Carrier by using Vlasov Beam Model
Kim, Yoo-Il ; Kim, Yong-Hwan ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 306~320
DOI : 10.3744/SNAK.2010.47.3.306
Modern ultra-large container carriers can be exposed to the unprecedented springing excitation from ocean waves due to their relatively low torsional rigidity. Large deck opening on the deck of container carriers tends to cause warping distortion of hull structure under wave-induced excitation, eventually leading to the higher chance of resonance vibration between its torsional response and incoming waves. To handle this problem, a higher-order B-spline Rankine panel method and Vlasov-beam FE model was directly coupled in the time domain, and the coupled equation was solved by using an implicit iterative method. In order to capture the complicated behavior of thin-walled open section girder, a sophisticated beam-based finite element model was developed, which takes into account warping distortion and shear-on-wall effect. Then, the developed beam model was directly coupled with the time-domain Rankine panel method for hydrodynamic problem by using the fixed-point iteration method. The developed computational scheme was validated through the comparison with the frequency-domain solution on the container carrier model in linear springing regime.
A Study on the Ship Resistance and Moment Prediction for Running Attitude of 30 Feet Catamaran Sailing Yacht
Park, Chung-Hwan ; Jang, Ho-Yun ; Jeong, Jin-Wook ; Lee, Byung-Sung ; Chun, Ho-Hwan ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 321~327
DOI : 10.3744/SNAK.2010.47.3.321
During sailing by wind-driven thrust on the sail, a catamaran sailing yacht generates leeway and heeling. For estimating resistance and moment prediction of a real ship by changing of running attitude, a model test of the ship has to be carried out. This study aims at establishing experimental techniques for a catamaran sailing yacht by changed attitude during running direction. Through the model test, drag and side force of the real ship are predicted. Also through experiment, rolling and yawing moments were considered.
A Study on Mathematical Model of Manoeuvring Motion of Manta-type Unmanned Undersea Vehicle at Large Attack Angles
Bae, Jun-Young ; Sohn, Kyoung-Ho ; Kim, June ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 328~341
DOI : 10.3744/SNAK.2010.47.3.328
The authors adopt the Unmanned Undersea Vehicle(UUV), which has taken the shape of manta(Sohn et al. 2006). They call here it Manta-type Unmanned Undersea Test Vehicle(MUUTV). MUUTV is designed with the similar concept of UUV called Manta Test Vehicle(MTV), which was originally built by the Naval Undersea Warfare Center, USA(Lisiewicz and French 2000, Sirmalis et al. 2001, U.S. Navy 2004). The present study deals with evaluation of extreme motion of MUUTV at large attack angles. Extreme motion contains, for example, rising and depth change due to operation of hovering thrusters attached to MUUTV, lateral motion due to ocean current applied to MUUTV at low advance velocity, and so on. Numerical simulation technique has been utilized. The previous mathematical model on manoeuvring motion of MUUTV(Bae et al. 2009a) is basically adopted. Based on the results of present model experiment on extreme motion, the mathematical model is revised and supplemented in order to describe extreme motion. The hydrodynamic derivatives related to extreme motion are obtained from present model experiment and the other derivatives are referred to previous work(Bae et al. 2009a).
Study on Infrared Image Generation for Different Surface Conditions with Different Sensor Resolutions
Choi, Jun-Hyuk ; Shin, Jong-Mook ; Kim, Jung-Ho ; Kim, Tae-Kuk ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 342~349
DOI : 10.3744/SNAK.2010.47.3.342
This paper is a foundation work in developing a software for generating infrared images from a scene with various objects. The spectral radiance received by a remote sensor is consisted of the self-emitted, reflected and scattered components. In general, the self-emitted component is the most important part for generating Infrared signatures from the object. In this paper, the infrared image generation considering various surface temperature and optical surface property of a flat plate is demonstrated in MWIR(
) and LWIR(
) regions for different spatial resolutions of the images. Resulting spectral radiance values in the MWIR(
) and LWIR(
) regions arrived at the infrared sensor are compared numerically and graphically by recognizing that they are strongly dependent on the surface conditions such as the surface temperature and the surface emissivity. And these infrared images are also shown to be strongly dependent on the resolutions of the infrared imaging devices as well. This study reveals that the surface conditions are more dependent on the radiance level from the surface while the resolution of the imaging device is more responsible for identifying the shape of object.
Comparative Study on Resistance Performance of Icebreaking Cargo Vessel according to Hull Form Variation by using Synthetic Ice and Refrigerated Ice
Lee, Seung-Ho ; Kim, Moon-Chan ; Chun, Ho-Hwan ; Shin, Byung-Chul ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 350~358
DOI : 10.3744/SNAK.2010.47.3.350
The present paper deals with the comparative study of resistance performance with refrigerated ice and synthetic ice according to the variation of hull form characteristics. The resistance test has been conducted in pack ice condition in each concentration condition. Stem angle has been chosen as main parameters for the variation of hull form characteristics. The correlation of performance between with the refrigerated ice and with the synthetic ice has been shown according to the variation for stem angles. The present study show the possibility of ice test in general towing tank with synthetic ice for the time-consuming research such as hull form optimization although that is confined in pack ice condition. The more parametric study for the properties of synthetic ice is expected to be conducted to have more close correspondence for the test results of refrigerated ice in near future.
Numerical Analysis of Generation and Propagation of Interfacial Soliton
Yun, Dong-Min ; Yoon, Bum-Sang ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 359~368
DOI : 10.3744/SNAK.2010.47.3.359
This paper describes the generation and propagation of internal solitary wave in a two-layer fluid system by numerical analysis. Characteristics of interfacial soliton such as wave type, wave height, wave celerity are investigated numerically with respect to an extent of initial disturbance, fluid thicknesses of the two fluids and etc. The difference between the internal wave propagation on sloping beach and flat bottom was also examined. Laboratory experiments were conducted in the wave flume and compared with the results of numerical computation for verification.
Numerical Analysis of Hydrodynamic Forces on a Floating Body in Two-layer Fluids
Kim, Mi-Geun ; Koo, Weon-Cheol ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 369~376
DOI : 10.3744/SNAK.2010.47.3.369
In this study, a radiation and a diffraction problems of a floating body in two-layer fluids were solved by the Numerical Wave Tank(NWT) technique in the frequency domain. In two-layer fluids, two different wave modes exist and the hydrodynamic coefficients can be obtained separately for each mode. The two-domain Boundary Element Method(BEM) in the potential fluid using the whole-domain matrix scheme was used to investigate the characteristics of wave forces, added mass and damping coefficients. The effects of the ratio of density and water depth in the lower domain were also evaluated and compared with given references.
Circular Motion Test Simulation of KVLCC1 Using CFD
Shin, Hyun-Kyoung ; Jung, Jae-Hwan ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 377~387
DOI : 10.3744/SNAK.2010.47.3.377
In this study, the turbulent free surface around KVLCC1 employed in the circular motion test simulation is numerically calculated using a commercial CFD(Computational Fluid Dynamics) code, FLUENT. Also, hydrodynamic forces and yaw moments around a ship model are calculated during the steady turning. Numerical simulations of the turbulent flows with free surface around KVLCC1 have been carried out by use of RANS equation based on calculation of hydrodynamic forces and yaw moments exerted upon the ship hull. Wave elevation is simulated by using the VOF method. VOF method is known as one of the most effective numerical techniques handling two-fluid domains of different density simultaneously. Boundary layer thickness and wake field are changed various yaw velocities of ship model during the steady turning. The calculated hydrodynamic forces are compared with those obtained by model tests.
Numerical Analysis of Chamber Flow and Wave Energy Conversion Efficiency of a Bottom-mounted Oscillating Water Column Wave Power Device
Koo, Weon-Cheol ; Kim, Moo-Hyun ; Choi, Yoon-Rak ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 388~397
DOI : 10.3744/SNAK.2010.47.3.388
A two-dimensional time-domain, potential-theory-based fully nonlinear numerical wave tank (NWT) was developed by using boundary element method and the mixed Eulerian-Lagrangian (MEL) approach for free-surface node treatment. The NWT was applied to prediction of primary wave energy conversion efficiency of a bottom-mounted oscillating water column (OWC) wave power device. The nonlinear free-surface condition inside the chamber was specially devised to represent the pneumatic pressure due to airflow velocity and viscous energy loss at the chamber entrance due to wave column motion. The newly developed NWT technique was verified through comparison with given experimental results. The maximum energy extraction was estimated with various chamber-air duct volume ratios.
Numerical Analysis of Added Resistance on Ships by a Time-domain Rankine Panel Method
Kim, Kyong-Hwan ; Kim, Yong-Hwan ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 398~409
DOI : 10.3744/SNAK.2010.47.3.398
This paper considers the numerical computation of added resistance on ships in the presence of incident waves. As a method of solution, a higher-order Rankine panel method is applied in time domain. The added resistance is evaluated by integrating the second-order pressure on the body surface. Computational results are validated by comparing with experimental data and other computational results on a hemi-sphere, a barge, Wigley hull models, and Series 60 hull, showing very fair agreements. The study is extended to the comparison between Neumann-Kelvin and double-body linearization approaches, and their differences are discussed.
Experimental Investigations on Slamming Impacts by Drop Tests
Shin, Hyun-Kyoung ; Kim, Sung-Chul ; Cho, Sang-Rai ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 410~420
DOI : 10.3744/SNAK.2010.47.3.410
When ships are sailing with large motions in rough waves, the slamming phenomenon occurs and the ships suffer from impulsive pressure loadings. Recently, ships are becoming lager and faster than before and it becomes more possible that the ships experience larger impacts on their bows and sterns. Many researchers have been performing the investigations on slamming experimentally and theoretically for a long time. Most of the research reported in the open literature focused on how to accurately estimate the amplitude of the peak pressure of slamming. According to the results of a recently published work, not only the amplitude of peak pressure but also the width of the peak may play an important role in predicting the extents of damage of impacted structures. The uncertainty of impulsive pressure loadings due to slamming has been indicated by many researchers. However, probabilistic treatments of the impulsive pressure loadings are few. In this study, drop tests were conducted on wedges having dead-rise angles of
. Not only the amplitude of peak pressure but also the width of peak pressure were measured. Furthermore, the variations of those values are also provided for the probabilistic approach of the slamming problem.
Analysis of an Elastic Boom Effect on the Dynamic Response of a Cargo
Park, Kwang-Phil ; Cha, Ju-Hwan ; Lee, Kyu-Yeul ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 421~429
DOI : 10.3744/SNAK.2010.47.3.421
In this paper, in order to analyze the dynamic response of a floating crane when it lifts a heavy cargo, the boom of the floating crane is considered as an elastic beam. The boom is divided into elements based on finite element formulation and the floating frame of reference formulation and nodal coordinates are employed to model the boom as a flexible body. As an extension of the previous study, in order to consider spatial motion in waves, the coupled equations of motions of the 6 degree of freedom (DOF) floating crane and 6 DOF cargo are developed based on the flexible multibody system dynamics. The 3 dimensional deformation of the elastic boom is considered with 18 DOF. The dynamic simulation of the floating crane and the cargo is performed under regular wave conditions with various cargo weights. Finally, the effects of the elastic boom on lifting cargo are discussed by comparing the simulation results between the elastic boom and a rigid boom.
Shape Design Optimization of Ship Structures Considering Thermal Deformation and Target Shape
Park, Sung-Ho ; Choi, Jae-Yeon ; Kim, Min-Geun ; Cho, Seon-Ho ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 430~437
DOI : 10.3744/SNAK.2010.47.3.430
In this paper, we develop a shape design optimization method for thermo-elastoplasticity problems that is applicable to the welding or thermal deformation problems of ship structures. Shell elements and a programming language APDL in a commercial finite element analysis code, ANSYS, are employed in the shape optimization. The point of developed method is to determine the design parameters such that the deformed shape after welding fits very well to a desired design. The geometric parameters of surfaces are selected as the design parameters. The modified method of feasible direction (MMFD) and finite difference sensitivity are used for the optimization algorithm. Two numerical examples demonstrate that the developed shape design method is applicable to existing hull structures and effective for the structural design of ships.
A Study on Evaluation Method of Member Forces on the Propulsion Shaft of Ship for Damage Protection of Clutch
Shin, Sang-Hoon ; Choe, Ick-Hung ; Ko, Dae-Eun ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 438~446
DOI : 10.3744/SNAK.2010.47.3.438
The purpose of this study is to establish the proper evaluation method of member forces on the propulsion shaft using strain gages to confirm bearing offset. The strain measurements to find out the bending moments of the shaft have been performed in the yard to be compared with the results of the shaft alignment analysis. The clutch of the propulsion shaft is highly sensitive to shear forces as well as bending moments and the necessity of the measurement of shear forces on the shaft for normal operation of the clutch is recently on the rise. In this study, an evaluation method of the member forces (bending moments and shear forces) of the shaft clutch based on the shaft strain measurement is established. Through the application of this method to the eight
LNG carriers, the safeties of the clutch systems are evaluated and the better bearing offsets are deduced for the LNG carriers. After adjusting the bearing offsets, all the sea trials of the eight LNG carriers are successfully carried out without any troubles.
A Study on the Design Sea-state Determination Using the IFOSM Method
Lee, Jae-Ohk ; Rho, Jun-Bumn ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 447~453
DOI : 10.3744/SNAK.2010.47.3.447
Response-based approach is getting more preferred in determining the design sea-state for offshore structures because traditional environment-based approach is known to yield a much conservative design condition. This paper introduces the inverse first-order second-moment (IFOSM) method as a response-based approach, which is expected to give a more feasible design condition at the cost of reasonable number of motion analyses. The IFOSM method is based on the theory of probability and adopts an optimization scheme to determine the design point. Both the design maximum response and design sea state can be obtained straightforwardly from the optimum. The IFOSM method has been applied to a turret-moored FPSO's design problem and showed its effectiveness in practical use.
A Performance-based Design Example of Smoke Extraction System Using CFD Fire Simulation
Lee, Jung-Moo ; Kim, Sung-Hoon ; Lee, Sung-Geun ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 454~461
DOI : 10.3744/SNAK.2010.47.3.454
The new SOLAS regulation permits the alternative design approach for the approval of designs which deviate from those where prescriptive rules apply. The new approach is being promoted by recent advances of noble designs such as those employing large public spaces in passenger ships. From the respect of fire safety, it is needed to show that the level of safety of new design is equivalent to what can be achieved from the prescriptive rules where the fire simulation is regarded to be the essential tool. This paper provides an overview of the process of performance-based design of the smoke extraction system in a cafeteria of a ROPAX. FDS, a CFD fire simulation software is used to show that the field-model software can improve the fire safety over what are expected from prescriptive rule sets or zone-model application.
Design of Course Keeping Controller for RIB-type USV Using a Pilot's Steering Pattern
Yun, Kun-Hang ; Yeo, Dong-Jin ; Yoon, Hyeon-Kyu ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 462~468
DOI : 10.3744/SNAK.2010.47.3.462
A new course keeping controller for RIB(Rigid Inflatable Boat)-type USV(Unmanned Surface Vehicle) is developed using pilot's steering pattern. A pilot's simple steering pattern is found out from various course change tests. It is used to course keeping algorithm, suitable for large course change more than 60 degrees. To validate the course keeping controller, sea trial tests are conducted. From sea trial test, new course keeping controller shows good performance with less overshoot, maximum roll angle less than
, which makes it possible that fast course changes without slip motion of USV.
A Study on the Bow Shape of Ice Breaking Vessel
Kim, Hyun-Soo ; Lee, Chun-Ju ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 3, 2010, Pages 469~475
DOI : 10.3744/SNAK.2010.47.3.469
The operation scenarios, types of ice, draft and propulsion system are important design point on the beginning stage of the ice breaking vessel. The concept of hull form in ice breaking vessel has to compromise the performance according to the operation route especially if ship is operating in ice and ice free water. The several hull forms were proposed to optimize the capability of the vessel in this paper. The effect of hull form according to type of ice is also discussing and explaining the ice resistance in each ice type as like pack ice, brash ice, level ice, rubble ice and ice ridge. The draft effect was examined and propulsion system for example FPP(Fixed pitch propeller), CPP(Controllable pitch propeller) and POD system was compared focusing on the propulsion efficiency.