• Journal of Ocean Engineering and Technology
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• v.19 no.3
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• pp.59-65
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• 2005

In today's industry, the butterfly valve has been used to control a flow effectively. However, it is difficult to have the existing structural optimization using field analysis from CFD to structure analysis when the structure is influenced by fluid. Therefore, an initial model of this study is to evaluate the stability of the valve using FEM and CFD. And, it selected variable using initial analysis results. Also, it accomplished the shape optimization design using the orthogonal arrangement and characteristic function. Research result, a few experiments showed the optimal results of there dimensional structures to be multi-objective.

• Knowledge Management Research
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• v.14 no.4
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• pp.19-46
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• 2013

This paper aims to show the learning process and the educational effects of Divide-and-Combine principles and State Models, which are included in the Butterfly Model for creative problem solving. In our State Models, there are Time State Model, Space State Model, and Whole-Parts State Model. We have taught middle school students (for 18 hours), high school students (for 24 hours), and undergraduate students (for 1 semester) about our proposed Models when they solved contradiction problems. Also, we have made the students learn our contradiction resolution algorithms by themselves based on team-based discussion. By learning and by using our Models, the students had the higher level of expertise in contradiction problems and had the growth mindset that made them have confidence in themselves and kept them challenging themselves about problems. Also, learning and solving with our Models improved the students' growth mindset as well as their problem-solving ability.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.181-186
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• 2007

Compressible flow characteristics in a butterfly valve is studied experimentally and numerically. The disk angle of the valve is changed as $0^{\circ}{\sim}30^{\circ}$. The SST model is used to represent the turbulent effect in the commercial code, CFX11. It was found that the numerical results are similar to the experimental ones, general discussions are given to the pressure distributions upon the disk angle of the valve.

• Wind and Structures
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• v.34 no.4
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• pp.321-334
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• 2022

Irregularity in plan shape is very common for any type of building as it enhances better air ventilation for the inhabitants. Systematic opening at the middle of the facades makes the appearance of the building plan as a butterfly one. The primary focus of this study is to forecast the force, moment and torsional coefficient of a butterfly plan shaped tall building. Initially, Computational Fluid Dynamics (CFD) study is done on the building model based on Reynolds averaged Navier Stokes (RANS) k-epsilon turbulence model. Fifty random cases of irregularity and angle of attack (AOA) are selected, and the results from these cases are utilised for developing the surrogate models. Parametric equations are predicted for all these aerodynamic coefficients, and the training of these outcomes are also done for developing Artificial Neural Networks (ANN). After achieving the target acceptance criteria, the observed results are compared with the primary CFD data. Both parametric equations and ANN matched very well with the obtained data. The results are further utilised for discussing the effects of irregularity on the most critical wind condition.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.306-321
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• 2014

This study aims to analyze difficulties that pre-service elementary teachers experience in investigating the life cycle of a common cabbage butterfly in person. As difficulties they face during the process of this research, they pointed out collecting eggs, observing molting, creating environments for a breeding cage, feeding, building a breeding cage, and making butterfly specimens. Out of all the environmental difficulties related to their school fields, they pointed out a difficulty of time management most of all, followed by placing a breeding cage in the classroom and the lack of microscopes for observation. In regard to difficulties related to their evaluations on students' activities, they found it difficult to evaluate students' activity with the life cycle of an insect in the aspect of knowledge and even to set evaluation criteria. Besides, many of them responded that it would be appropriate to evaluate a research on the life cycle of an insect through a portfolio or an observation journal. In regard to difficulties in terms of teachers' knowledge, they found it difficult to understand insect molting, metamorphoses, complete metamorphoses, incomplete metamorphoses, the structure of an insect body, and how to distinguish a female insect from a male one. In regard to the application of class models, they knew it is important for students to have various experiences through direct observation, so the experience-based learning model was proper for the process of observing the life cycle of a common cabbage butterfly. However, they found it difficult for students to observe each stage of the life cycle in person.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.17-22
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• 2020

This study investigates the flow efficiency based on valve shape. Three models are designed for the throttle, ball, and butterfly valves. Results show that Flow Model B, representing the ball valve, demonstrates the fastest flow rate among the three models. Although pressure contours are present on the side surfaces of the valve wings for all models, Flow Model C, representing the butterfly valve, demonstrates to be under the least amount of applied pressure among the three models. The results of this study can be utilized to efficiently control the air flow through various types of valves.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.4 s.247
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• pp.379-386
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• 2006

The hyper-elastic material has been used gradually and its range was extended all over the industry. The performance prediction of hyper-elastic material was required not only experimental methods but also numerical methods. In this study, we presented the process how to use numerical method for hyper-elastic material and applied it to seat-ring of butterfly valve. The finite element analysis was executed to evaluate the mechanical characteristics of hyper-elastic material. And the optimum model considered conditions and features. According to that model, the load conditions were obtained by using CFD analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1315-1321
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• 2005

Using hyper-elastic material has been increased gradually and its range was extended all over the industrial. In addition, the performance prediction of this material was required not only experimental methods like metal material but also numerical methods. In this study, we presented the process how to use numerical method for hyper-elastic material and then, it was applied for seat-ring of butterfly valve by using this process. The finite element analysis was executed to evaluate the mechanical characteristics of hyper-elastic material and search the optimum model considered conditions and features. According to that model the coefficient was obtained by using Contact analysis.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.4
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• pp.327-332
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• 2012

International Towing Tank Conference (ITTC) recommended verifying a ship's ability to move transversely at zero forward speed without altering heading by a crabbing test. In sea trial, all available propellers/rudders/thrusters should be used to find the maximum possible transverse speed. For estimating crabbing ability in the design stage, tests to estimate possible swaying force and yawing moment range using all available propellers/rudders/thrusters are conducted. By butterfly diagram, which compares possible swaying force and yawing moment range with external swaying force and yawing moment by wind, a ship's crabbing ability can be estimated. In this study, model tests of a cruise vessel equipped with bow thrusters and POD system were conducted to find out her crabbing ability in the design stage. To mimic quay condition, a model quay-wall was set in the towing tank.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.6
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• pp.359-366
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• 2014

This paper considered optimization method of appending a shape on a disc in an attempt to improve core functions, which are inherent in flow characteristics. The paper also verifies the optimization method of appendage shape with a Class 150 200A Butterfly valve. Then the design of experiment (DOE) with an orthogonal array is performed to analyze the effect of form parameters by grey relational analysis and analysis of mean (ANOM). And this study sets flow coefficient as an object functions for optimization, and the conventional disc model and the optimal appendage shape on disc model are compared by computational fluid analysis. The paper concludes that an optimal appendage shape on disc model achieves wider usability by a wider operating range.