• Title/Summary/Keyword: intermediate boundary condition

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Survey evaluation of thermal boundary condition in the inside and outside of double skin facade

  • Shin, Hyun-Cheol;Jang, Gun-Eik
    • KIEAE Journal
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    • v.15 no.4
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    • pp.29-35
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    • 2015
  • Purpose: Double skin facade is a representative advantageous passive technology of building skin in the aspect of energy saving and environment improvement, reduces heat loss with buffer space in winter season and enhances indoor air and comfort of residents by activating natural ventilation in mid-season. However, in summer season, temperature increase in the intermediate space due to solar energy from exterior transparent skin could be a potential problem; also, relatively weak buoyancy of air caused by low density difference between double-skin facade could increase cooling load as air of intermediate space in high temperature hangs. However, proof data is insufficient to objectify such phenomenon. Method: In this study, researchers surveyed air temperature of intermediate space and airflow and diagnosed its cause targeting on applied multistory facade in the building which gives thermal uncomfort to residents. Also, the researchers produced Solar-air heat transfer coefficient meter, measured thermal boundary condition of double-skin facade, and presented the result of measurement as an objectified verification material regarding overheating phenomenon in the intermediate space of double-skin facade in summer season. Result: Inefficient condition was verified that total heat increases and overheating due to insufficient natural ventilation in multistory facade. In addition, logic behind preceding research was objectified and verified regarding high temperature phenomenon in the intermediate space which could increase cooling load in summer season.

FINITE ELEMENT ANALYSIS FOR A MIXED LAGRANGIAN FORMULATION OF INCOMPRESSIBLE NAVIER-STOKES EQUATIONS

  • Kim, Hong-Chul
    • Journal of the Korean Mathematical Society
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    • v.34 no.1
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    • pp.87-118
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    • 1997
  • This paper is concerned with a mixed Lagrangian formulation of the wiscous, stationary, incompressible Navier-Stokes equations $$ (1.1) -\nu\Delta u + (u \cdot \nabla)u + \nabla_p = f in \Omega $$ and $$ (1.2) \nubla \cdot u = 0 in \Omega $$ along with inhomogeneous Dirichlet boundary conditions on a portion of the boundary $$ (1.3) u = ^{0 on \Gamma_0 _{g on \Gamma_g, $$ where $\Omega$ is a bounded open domain in $R^d, d = 2 or 3$, or with a boundary $\Gamma = \partial\Omega$, which is composed of two disjoint parts $\Gamma_0$ and $\Gamma_g$.

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A study on Optimum Design of the Frame for Mechanical Press (기계식 프레스 Frame의 최적설계에 관한 연구)

  • Jo, Baek-Hui;Ryu, Byeong-Sun
    • 연구논문집
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    • s.22
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    • pp.65-74
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    • 1992
  • This paper aims at calculating optimum design dimensions to minimize the weight satisfied strain and stress intensity of the frame while loading maximum weight into a mechanical press in the static condition. Analysis of the frame was carried out by using the FEM, then the optimum condition was obtained by using these data. As modeling in the finite element analysis has great impact on the reliablity of analysis results, the analyzed object was selected a 150-ton mechanical press of J Company, the part little affected to structural rigidity was simplified, the load condition was considered in the only maximum load, the boundary condition was used by giving symmetric displacement due to symmetric boundary condition, the finite element was applied a linear membrane element. An intermediate processor program applied the normal ANSYS to analyze finite elements was developed, and the design sensitivity was calculated. This program was applied to the optimum design.

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Design Characteristics Analysis for Very High Temperature Reactor Components (VHTR 초고온기기 설계특성 분석)

  • Kim, Yong Wan;Kim, Eung Seon
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.12 no.1
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    • pp.85-92
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    • 2016
  • The operating temperature of VHTR components is much higher than that of conventional PWR due to high core outlet temperature of VHTR. Material requirements and technical issues of VHTR reactor components which are mainly dominated by high temperature service condition were discussed. The codification effort for high temperature material and design methodology are explained. The design class for VHTR components are classified as class A or B according to the recent ASME high temperature reactor design code. A separation of thermal boundary and pressure boundary is used for VHTR components as an elevated design solution. Key design characteristics for reactor pressure vessel, control rod, reactor internals, graphite reflector, circulator and intermediate heat exchanger were analysed. Thermo-mechanical analysis of the process heat exchanger, which was manufactured for test, is presented as an analysis example.

Dynamic Response of a Beam Including the Mass Effect of the Moving Loads (이동 하중의 질량효과를 고려한 보의 동적응답)

  • 최교준;김용철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.61-68
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    • 1991
  • The system such as railway bridge can be modelled as the restrained beam with intermediate supports. This kind of structures are subject to the moving load, which has a great effect on dynamic stresses and can cause sever motions, especially at high velocities. Therefore, to analyze the dynamic characteristics of the system due to the moving load is very important. In this paper, the governing equation of motion of a restrained beam subjected to the moving load is derived by using the Hamilton's principle. The orthogonal polynomial functions, which are trial functions and satisfying the geometric and dynamic boundary conditions, are obtained through simple procedure. The dynamic response of the system subjected to the moving loads is obtained by using the Galerkin's method and the numerical time integration technique. The numerical tests for various constraint, velocity and boundary conditions were preformed. Furthermore, the effects of mass of the moving load are studied in detail.

Shear Strength of Plate Girder (플레이트거더의 전단내력)

  • Choi, Chui-Kyung;Kim, Kyu-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.2
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    • pp.169-176
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    • 2003
  • In the design of plate girder web panels, it is required to evaluate accurately the elastic buckling strength under shear, whether or not the post-buckling strength is accounted for. Currently, elastic shear buckling coefficient of web panels stiffened by transverse intermediate stiffeners are determined by assuming conservatively that web panels are simply supported at the juncture between the flange and web. Although the notion of the real boundary condition at the juncture of the web and the flanges to be somewhere between simple and fixed has been recognized from early days, the boundary condition has been conservatively assumed, mainly due to lack of means to evaluate it in a rational manner. In this paper, a series of numerical analyses and experiments is carried out to provide a simple equation with some parameters especially the flange-web thickness ratio.

MAGNETIC HELICITY INJECTION DURING THE FORMATION OF AN INTERMEDIATE FILAMENT

  • Jeong, Hye-Won;Chae, Jong-Chul;Moon, Y.J.
    • Journal of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.9-15
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    • 2009
  • A necessary condition for the formation of a filament is magnetic helicity. In the present paper we seek the origin of magnetic helicity of intermediate filaments. We observed the formation of a sinistral filament at the boundary of a decaying active region using full-disk $H_{\alpha}$ images obtained from Bi Bear Solar Observatory. We have measured the rate of helicity injection during the formation of the filament using full-disk 96 minute-cadence magnetograms taken by SOHO MDI. As a result we found that 1) no significant helicity was injected around the region (polarity inversion line; PIL) of filament formation and 2) negative helicity was injected in the decaying active region. The negative sign of the injected helicity was opposite to that of the filament helicity. On the other hand, at earlier times when the associated active region emerged and grew, positive helicity was intensively injected. Our results suggest that the magnetic helicity of the intermediate filament may have originated from the helicity accumulated during the period of the growth of its associated active region.