• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.395-398
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• 2007

In nature, the swallowtail butterfly is known to be a versatile flyer using gliding and flapping efficiently. Furthermore, it has long tails on the hind-wing that may be associated with the enhancement of the gliding performance. In the present study, we investigate the aerodynamic property of swallowtail butterfly wing in gliding. We use an immersed boundary method and conduct a numerical simulation at the Reynolds numbers of 1,000 - 3,000 based on the free-stream velocity and the averaged chord length for seven different attack angles. As a result, we clearly identify the existence of the wing-tip and leading-edge vortices, and a pair of the streamwise vortices generated along the hind-wing tails. Interestingly, at the attack angle of $10^{\circ},$ hairpin vortices are generated above the center of the body and travel downstream.

• 한국기계가공학회지
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• 제11권5호
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• pp.94-98
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• 2012

Butterfly valves are usually used by the plumbing systems in plant engineering field. Valves are used for controlling the flow rate and pressure of fluid. In order to control the flow rate using butterfly valve, the position control of valve disc should be designed. However, since there are lots of uncertain disturbance in plumbing system, the robust control system should be considered. Therefore, the sliding mode control system using neural network algorithm is proposed in this paper. The proposed control system provides the estimating method using neural network for the unmeasurable disturbance in the plumbing system. The performance of the proposed control system is evaluated through computer simulations.

• 한국해양공학회지
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• 제19권3호
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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.

• 한국기계가공학회지
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• 제11권4호
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• pp.62-66
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• 2012

The objective of this study is to simulate flow coefficient and flow characteristics such as velocity and pressure distribution for butterfly valve. Butterfly valves used in this study are 65A, 80A and 100A, in size, and of which the opening angle is varied. The flow coefficient, Kv, increases as the disc opening and valve size are increase. When using flow coefficient meanwhile specific curve of flow rate is also determined. The flow velocity between disc and seat increase as the disc opening decrease. The re-circulating zone is also observed in downstream behind disc.

• 한국화재소방학회논문지
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• 제16권4호
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• pp.59-64
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• 2002

버터플라이 밸브의 압력손실과 캐비테이션에 대한 유동특성 연구를 수행하였다. 밸브의 열림각에 대한 압력손실계수는 Carnot 방정식을 응용하여 수식화하였다. 캐비테이션(캐비테이션의 발단, 슈퍼 캐비테이션, 캐비테이션 손상, 초킹 캐비테이션과 같은)은 밸브의 압력손실계수로부터 예측되었다. 압력손실과 캐비테이션 예측은 밸브의 열림각에 대한 두께 비의 변화에 따라 수행하였다. 예측 데이터는 버터플라이 밸브를 개발하는데 필요한 엔지니어링 데이터로 활용하고자 한다.

• 열처리공학회지
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• 제10권3호
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• pp.188-197
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• 1997

Effect of martensite morphology on damping capacity and hardness of Fe-Ni-C martensitic alloys were studied. The morphologies of martensite such as lath, butterfly, lenticular and thin plate were prepared by adjusting nickel content and austenite grain size. The hardness increased in order of lath, lenticular, thin plate, butterfly. The damping capacities of the lath and butterfly martensites were higher than those of the other two morphologies, indicating that the dislocation substructure is more effective in the damping capacity than the twin substructure. Especially, the butterfly martensite showed the highest damping capacity among these morphologies because of presence of not tangled but free dislocations in there.

• The Korean Journal of Ecology
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• 제26권4호
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• pp.199-202
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• 2003

According to the energy hypothesis, the energy input per unit area primarily determines species richness in regions of roughly equal area. Some energy-related ecological research included identification of major climatic variables to determine regional species richness. In this study, the local butterfly species richness was examined to find out whether weather variables affected the local distribution or abundance of butterfly populations. Butterfly monitoring data from May 2001 to April 2002 taken at Mt. Yudal, Mokpo, in the southwestern part of Korea, and six weather variables (monthly mean values of temperature, precipitation, evaporation, wind speed, air pressure, and sunlight) were analyzed. Multiple regression analysis showed that only temperature explained 80% and 70% of the variability of log-transformed number of species and individuals, respectively, indicating that temperature played an important role in local species richness. Furthermore, global warming could affect the abundance and distribution of butterflies regionally as well as locally.

• 한국유체기계학회 논문집
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• 제14권3호
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• pp.5-9
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• 2011

Butterfly valves are widely used in current industry to control the fluid flow. They are used for both on-off and throttling applications involving large flows at relatively low pressure-drop especially in large size pipelines. In this study, we carried out the structure analysis of the butterfly valve components according to pressure testing of the industrial standard. the numerical simulation was performed by using ANSYS Workbench. The reliability of valve is evaluated under the investigation of the strain rate, the leak test and the durability of the valve.

• 한국유체기계학회 논문집
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• 제14권4호
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• pp.31-37
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• 2011

Linear curve or hyperbolic curve interpolation equations have been used to represent loss coefficient of butterfly valve according to a certain opening(for example, each 10 degree up to 90 degree) so far, and these equations are not precise and inconvenient to use with computer programming. Method of representing loss coefficient of butterfly valve using experiment data with several equations is presented and It is verified that log equation is most precise and convenient to use with computer programming in this research.

• 한국환경복원기술학회지
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• 제5권4호
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• pp.80-88
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• 2002

Comprehensive landscape architectural services provided from schematic design through construction document for this 22,000 square foot, linear, urban rooftop garden situated on top of an in-ground parking garage. The Butterfly Garden serves as a green buffer between a fully renovated historic, seven story condominium building and 15 newly constructed luxury town houses. The park was developed with the cooperation and input from the Washington Butterfly Society during an intensive design charette. The garden will one day soon serve as an ecological amenity to the residents of Alban Towers as well as the surrounding community.