• Journal of the Society of Naval Architects of Korea
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• v.42 no.1 s.139
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• pp.50-56
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• 2005

The performance of Traditional Korean Fishing Boat is surveyed based on Report on Investigation of Korean Fishing Boat. The characteristics of Traditional Korean fishing Boat of hull form, rudder, sail are studied from the view point of modern sailing boat design. As a result we find her hull form is an excellent candidate of mother ship for modern boat design and the great sized rudder of Traditional Korean Fishing Boat makes a role of the centerboard of modern sailing host. And also we find the sail of Traditional Korean fishing Boat is more useful for sailing against the wind direction than an ordinary Lug sail.

• Journal of Advanced Marine Engineering and Technology
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• v.12 no.2
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• pp.46-56
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• 1988

The author has presented a new approach to design hydrofoil section shapes in consideration of viscous for marine propeller blades. In suction sides of propeller blades, the pressure distribution on hydrofoil sections in non-cavitating flow should be examined before the study of cavitation characteristics. Generally, the calculation results for hydrofoil conformal mapping method by which neglect viscous effects do not agree with experimental ones. Moreover, another papers reported that laminar separation bubble and transition played an important role on the cavitation inception. From these considerations, it is very important to study the viscous effects of the hydrofoil sections, especially the mechanism separation bubble and the apparent thickness of hydrofoil section. Therefore, the new design method of hydrofoil sections in consideration of viscous effects in comparison to the airfoil section should be studied. In designing the new hydrofoil section shapes, based on Eppler theory, the author tried to give the peak negative pressure in leading edge region for NACA airfoil in consideration of viscous effects without turbulent boundary layer separation as much as possible. The design method was verified from the fact that the boundary characteristics was improved and the lifts of new hydrofoils were slightly in creased in comparison to these of NACA 16-012 symmetrical, NACA 4412 non-symmetrical airfoils.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7878-7884
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• 2015

Marine sea water pump with impeller using carbon fiber block was developed to prevent the impeller corrosion by the salinity. A numerical analysis was carried out in order to optimize the impeller and volute design for marine sea water pump and to investigate the sensitivity of the related parameters(impeller thickness, surface roughness) using CFD commercial code. The impeller thickness is limited because of the weight. Since the impeller using the carbon fiber lights, the thickness which has a maximum efficiency can be used. The results show that the surface roughness leads to an 7% reduction in pump efficiency.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.2
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• pp.121-128
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• 2021

According to the increasing interest and demand for the Autonomous Surface Vessels (ASV), the autonomous navigation system is being developed such as obstacle detection, avoidance, and path planning. In general, autonomous navigation algorithm controls the ship by detecting the obstacles with various sensors and planning path for collision avoidance. This study aims to construct and prove autonomous algorithm with integrated various sensor using the Robot Operating System (ROS). In this study, the safety zone technique was used to avoid obstacles. The safety zone was selected by an algorithm to determine an obstacle-free area using 2D LiDAR. Then, drift angle of the ship was controlled by the propulsion difference of the port and starboard side that based on PID control. The algorithm performance was verified by participating in the 2020 Korea Autonomous BOAT (KABOAT).

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.81-86
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• 2019

Although the localization rate of shipbuilding and marine equipment goods is set to be 70 percent by 2020, but the localization rate of equipment and materials for shipbuilding and marine facilities is currently 10 to 30 percent. For Korea's Big 3 shipbuilders, which build 70 percent of the world's largest shipbuilders, localization of shipbuilding equipment and equipment is an essential factor. In particular, there is a growing need to localize equipment and materials in terms of the number of lead standards and A/S. It is expected that there will be a rapid expansion of LNG carriers in the future, and it is necessary to develop equipment and equipment materials of LNG ships. In this study, the design and manufacture of LNG vessel equipment was conducted. Design and basic performance tests of 4-inch QCDC for LNG bunkering were conducted.

• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.241-253
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• 2013

A Shipbuilding design program used in the shipbuilding industry tends to be shifted from the TRIBON software to the AM(AVEVA MARINE) software these days. Many large domestic shipbuilding companies have been using the AM instead of the TRIBON. New design software requires education programs for the necessary personnel. However the education programs for the AM are largely based on offline education. They suffer from constraints in space and time, and from high costs. This paper describes a development of online contents for the AM software that are focused for cyber education. It covers the applied process and the organization of the contents. The details of the development decisions including the security issue for the contents are described also.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.47-53
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• 2002

The hydraulic design optimization and performance analysis of mixed-flow pumps for waterjet marine vehicle propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study the conceptual design optimization has been formulated with a non-linear objective function to minimize the fluid dynamic losses and then the commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. New designed mixed-flow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree very well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction methods presented herein can be used efficiently as a unified hydraulic design process of mixed-flow pumps for waterjet marine vehicle propulsion.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.1
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• pp.58-66
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• 2010

Topology design optimization is a method to determine the optimal distribution of material that yields the minimal compliance of structures, satisfying the constraint of allowable material volume. The method is easy to implement and widely used so that it becomes a powerful design tool in various disciplines. In this paper, a large-scale topology design optimization method is developed using the efficient adjoint sensitivity and optimality criteria methods. Parallel computing technique is required for the efficient topology optimization as well as the precise analysis of large-scale problems. Parallelized finite element analysis consists of the domain decomposition and the boundary communication. The preconditioned conjugate gradient method is employed for the analysis of decomposed sub-domains. The developed parallel computing method in topology optimization is utilized to determine the optimal structural layout of human powered vessel.

• Ocean Systems Engineering
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• v.9 no.2
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• pp.111-133
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• 2019

Flow through a scaled horizontal axis marine current turbine was numerically simulated after validation and the turbine design was optimized. The computational fluid dynamics (CFD) code Ansys-CFX 16.1 for numerical modeling, an in-house blade element momentum (BEM) code for analytical modeling and an in-house surrogate-based optimization (SBO) code were used to find an optimal turbine design. The blade-pitch angle (${\theta}$) and the number of rotor blades (NR) were taken as design variables. A single objective optimization approach was utilized in the present work. The defined objective function was the turbine's power coefficient ($C_P$). A $3{\times}3$ full-factorial sampling technique was used to define the sample space. This sampling technique gave different turbine designs, which were further evaluated for the objective function by solving the Reynolds-Averaged Navier-Stokes equations (RANS). Finally, the SBO technique with search algorithm produced an optimal design. It is found that the optimal design has improved the objective function by 26.5%. This article presents the solution approach, analysis of the turbine flow field and the predictability of various surrogate based techniques.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.272-280
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• 2022

The first step is to determine the principal dimensions of the design ship, such as length between perpendiculars, beam, draft and depth when accomplishing the design of a new vessel. To make this process easier, a database with a large amount of existing ship data and a regression analysis technique are needed. Recently, deep learning, a branch of artificial intelligence (AI) has been used in regression analysis. In this paper, deep learning neural networks are used for regression analysis to find the regression function between the input and output data. To find the neural network structure with the highest accuracy, the errors of neural network structures with varying the number of the layers and the nodes are compared. In this paper, Python TensorFlow Keras API and MATLAB Deep Learning Toolbox are used to build deep learning neural networks. Constructed DNN (deep neural networks) makes helpful in determining the principal dimension of the ship and saves much time in the ship design process.