• 한국지진공학회논문집
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• 제7권2호
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• pp.21-27
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• 2003

일반적으로 유체-구조물 상호작용을 고려한 유체속 구조물들의 지진 및 진동해석에는 주어진 시스템에 대한 유체부가질량을 추정하여 구조물관 연계하는 단순해석 방법을 주로 사용한다. 실제로 유체속 구조물의 응답특성은 유체부가질량 뿐만 아니라 유체점성으로 인한 감쇠영향을 받으며 이들은 모두 연계항을 갖는 복잡한 행렬 형태로 나타난다. 본 연구에서는 비점성 및 점성 유체에 대한 Navier-Stokes 지배방정식의 선형화를 통한 유한요소 정식화를 유도하였다. 이를 이용하여 유한요소 해석 프로그램을 작성하고 6각형 단면특성을 갖는 액체금속로 노심에 대하여 덕트집합체 사이의 유체간격과 레이놀즈수 변화에 따른 유체부가질량과 유체감쇠에 대한 유한 요소 해석을 수행한 결과, 유체간격이 줄어들수록 유체부가질량은 유체점성의 영향을 크게 받고 유체감쇠는 점성으로 인하여 레이놀즈수의 영향을 크게 받는 것으로 나타났다. 또한 편심을 갖는 동축원통에 대한 유한요소 해석결과, 편심이 증가할수록 유체부가질량은 크게 증가하지만 유체감쇠는 편심이 작은 경우 거의 변화가 없으며 어느 일정 수준이상으로 편심이 커질 경우에는 크게 영향을 받는 것으로 나타났다.

• 대한가정학회지
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• 제28권1호
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• pp.9-20
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• 1990

The purpose of this study was to identify the original quality of design by Issey Miyake and the relationship between the modern expression of art and his design regarding the form, internal symbolism, and Japanese tradition. The bottom current of the modern expression of art has two current: intention to autonomy or purism and intention to contingency. According to analysis of Miyake's design, it was found that Miyake has directed his attention to coexistance of fabric and the body with a pure fluid sculptured form based on two dimensional rectangular fabric. And his plasticity of dress was also made against the fitted structure form and idea of Haute Couture, emphasizaing on his own creativity and insisting on a creative collaboration between the designer and wearer. Finally, the fact that his design was inflnenced by traditionalison of Japanese costume and current modern expression of art was proved.

• 대한조선학회논문집
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• 제44권6호
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• pp.564-571
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• 2007

In the present study, stern form optimization has been carried out using computational fluid dynamics (CFD) techniques. The viscous pressure drag has been minimized to optimize stern shape. Parametric modification function has been used to modify the shape of the hull. By the use of the parametric modification function and algebraic scheme to grid manipulation, the initial ship geometry was easily deformed according to change of design parameters. For purpose of illustration, KRISO 319K VLCC (KVLCC) is chosen for example ship to demonstrate stern form optimization. The numerical results indicate that the optimized hull yields a reduction in viscous resistance.

• Advances in Computational Design
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• 제5권4호
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• pp.363-380
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• 2020

In this paper, a cylindrical shell is immersed in a non-viscous fluid using first order shell theory of Sander. These equations are partial differential equations which are solved by approximate technique. Robust and efficient techniques are favored to get precise results. Employment of the Rayleigh-Ritz procedure gives birth to the shell frequency equation. Use of acoustic wave equation is done to incorporate the sound pressure produced in a fluid. Hankel's functions of second kind designate the fluid influence. Mathematically the integral form of the Lagrange energy functional is converted into a set of three partial differential equations. Throughout the computation, simply supported edge condition is used. Expressions for modal displacement functions, the three unknown functions are supposed in such way that the axial, circumferential and time variables are separated by the product method. Comparison is made for empty and fluid-filled cylindrical shell with circumferential wave number, length- and height-radius ratios, it is found that the fluid-filled frequencies are lower than that of without fluid. To generate the fundamental natural frequencies and for better accuracy and effectiveness, the computer software MATLAB is used.

• 한국지진공학회논문집
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• 제5권5호
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• pp.25-33
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• 2001

현재 국내에서 개발중인 액체금속로 원자로구조물의 내진설계 및 지진해석을 위하여 원자로내부에 존재하는 유체-구조물 상호작용을 고려한 단순지진해석 모델링 개발이 필수적이다. 이를 위하여 본 논문에서는 유체속에 잠긴 동축원통 구조물의 유체부가질량에 대한 이론적 배경을 검토하였으며 기존의 유체부가질량법을 고려하여 시간이력 지진응답해석을 수행할 수 있는 Runge-Kutta 수치해석 알고리즘을 사용한 해석코드를 개발하였다. 개발된 지진해석코드를 사용하여 유체속에 잠긴 두개의 동축원통 구조물의 진동특성과 지진응답에 대한 유체부가질량의 영향을 살펴보았다. 적용예로서 두개의 동축원통에 대한 단순지진해석모델을 가정하고 유체부가질량을 고려한 진동특성해석과 지진응답해석을 수행한 결과 유체가 채워진 동축원통 구조물은 유체와의 상호작용으로 인하여 구조물의 진동특성과 지진응답특성이 크게 영향을 받으며 지진응답해석시 연계항을 포함한 유체부가질량의 영향을 신중하게 고려할 필요가 있는 것으로 나타났다.

• 자원환경지질
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• 제25권3호
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• pp.283-296
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• 1992

The Keumryeong deposits is a low grade copper deposits in which copper minerals form disseminated grains and thin veinlets in felsic volcanics seem to be dacite. Alteration of the volcanics consists mainly pervasive propylitization and silicification. Potassic alteration characterized by biotite developed locally adjacent to southwestern contact of granodiorite body. Principal sulfide minerals in altered zone are mainly pyrite and lesser chalcopyrite. Chalcopyrite content in potassic zone is relatively higher than that of surrounding propylitized zone. Pyrite and chalcopyrite accompanies magnetite, molybdenite, sphalerite, pyrrhotite, arsenopyrite, pentlandite, marcasite, hematite, ilmenite, rutile, bismuthinite and native Bi as disseminations, veinlets and knots. Granodiorite body is propylitized and contains veinlets of pyrite, chalcopyrite and molybdenite. Fluid inclusions in sulfide-bearing quartz veinlets and quartz grains of felsic volcanics and granodiorite in altered zone consist of liquid-rich, vapor-rich, $CO_2-bearing$ and halite-bearing inclusions. These four types of inclusion intimately associated on a microscopic scale and indicate condensing or boiling of ore fluid during mineralization. Homogenization temperature of coexisting fluid inclusions are mostly in the range of 350 to $450^{\circ}C$. High salinity fluid contains 28.6 to 48.4 weight percent NaCI equivalent and moderate salinity fluid cotains 0.5 to 12.5 weight percent NaCl equivalent. Pressure estimated from $CO_2$ mole fraction of $CO_2-bearing$ inclusion range 160 to 375 bars. The Kigu copper deposits is a fissure filling copper vein developed 500 m south from the Keumryong deposits. Mineralogy and fluid inclusion data of the Kigu deposits are similar to that of the Keumryeong deposits. Homogenization temperature of fluid inclusions from the Kigu deposits are reasonable agreement with temperature estimated from sulfidation curve of cubanite-chalcopyrite-pyrite-pyrrhotite and pyrite-pyrrhotite mineral assemblages. Not only mineral occurrence and wall rock alteration in the Keumryeong deposits but also fluid inclusion data such as temperature, salinity, pressure and boiling evidences are similar to those of porphyry copper deposits.

• Advances in nano research
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• 제15권5호
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• pp.401-410
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• 2023

Vibration investigation of fluid-filled three layered cylindrical shells is studied here. A cylindrical shell is immersed in a fluid which is a non-viscous one. Shell motion equations are framed first order shell theory due to Love. These equations are partial differential equations which are usually solved by approximate technique. Robust and efficient techniques are favored to get precise results. Employment of the wave propagation approach procedure gives birth to the shell frequency equation. Use of acoustic wave equation is done to incorporate the sound pressure produced in a fluid. Hankel's functions of second kind designate the fluid influence. Mathematically the integral form of the Lagrange energy functional is converted into a set of three partial differential equations. It is also exhibited that the effect of frequencies is investigated by varying the different layers with constituent material. The coupled frequencies changes with these layers according to the material formation of fluid-filled FG-CSs. Throughout the computation, it is observed that the frequency behavior for the boundary conditions follow as; clamped-clamped (C-C), simply supported-simply supported (SS-SS) frequency curves are higher than that of clamped-simply (C-S) curves. Expressions for modal displacement functions, the three unknown functions are supposed in such way that the axial, circumferential and time variables are separated by the product method. Computer software MATLAB codes are used to solve the frequency equation for extracting vibrations of fluid-filled.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2000년도 추계 학술대회논문집
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• pp.72-77
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• 2000

This paper presents the results of the application of a computational fluid dynamics algorithm for the simulation of plasma flows of arc-heated jet. The underlying physical model is based on the axisymmetric form of the conservation equations that are coupled with an arc model including Ohm heating, electromagnetic forces. The arc model given as a source term in fluid dynamic equations is determined by a solution of electric potential field governed by an elliptic partial differential equation. The governing equation of electric field is loosely coupled with fluid dynamic equations by an electric conductivity that is a function of state variables. However, the electric fields and flow fields cannot be solved In fully coupled manner, but should be solved iteratively due to the different characteristics of governing equations. With this solution approach, several applications of arc flow analysis will be presented including Arc Thruster and Circuit Breaker.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제15권3호
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• pp.201-222
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• 2011

In the present work, the mathematical model of wire coating in a straight annular die is developed for unsteady second grade fluid in the form of partial differential equation. The Optimal Homotopy Asymptotic Method (OHAM) is applied for obtaining the solution of the model problem. This method provides us a suitable way to control the convergence of the series solution using the auxiliary constants which are optimally determined.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.751-755
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• 1995

It become more difficult to anticipate the performance of fluid power systems as the number of components increases because of nonlinearrities inherent in hydraulic components. In this situation, the computer simulation technique can be an effective tool in the analysis and design of fluid power systems. In this paper, simulation results are presented for dynamic characteriatics of a knuckle crane. Simple models for hydraulic components and relatively detailed motion equations for attachments are used. the simulation reaults are very close to those of experiments. The simulation is performed using a simulation package developed with object-oriented method. This package provides the encironment that user can construct desirct desired circuits form the component library, checks the continuity and compatibility conditions automatically and executes simulation