• Title, Summary, Keyword: Complex Geometry

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Computation of Thermal Flow for Automotive Lamp by Using Geometric Octree Method (기하학적 Octree 격자생성법을 이용한 자동차 헤드램프 내부의 열유동 계산)

  • Sah Jong-Youb;Park Jong-Ryul;Kang Dong-Min
    • 한국전산유체공학회:학술대회논문집
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    • pp.152-156
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    • 2001
  • Three dimensional orthogonal grid generation is able to control effectively the grid spacing near the boundaries, but there are some difficulty to meshing complex geometry. The mesh complex geometry by orthogonal grid generation method must divide block of geometry It is required a careful skill, and long time. Its also difficulty to make unstructured mesh on complex geometry. Particularly, three dimensional geometry must have more time and effort. Recently, there have been growing interests in mesh generation of complex grometry, aslike an automobile headlamp, the heart. The method of easily meshing complex geometry is resarched to solve them. We suggest octree grid into one among these methods. As octrce grid is automaticaly adapted at the boundaries by determine the level operations to control the grid spacing near the boundaries are unnecessary. In this paper we showed throe dimensional mesh generation, and heat-flow analysis on the octree mesh.

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COMPUTATION OF SOUND SCATTERING IN 3D COMPLEX GEOMETRY BY BRINKMAN PENALIZATION METHOD (Brinkman Penalization Method를 통한 복잡한 3D 형상 주위의 음향 전파 연구)

  • Lee, S.H.;Lee, J.B.;Kim, J.U.;Moon, Y.J.
    • Journal of computational fluids engineering
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    • v.17 no.4
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    • pp.103-109
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    • 2012
  • Sound scattering in 3D complex geometry is difficult to model with body-fitted grid. Thus Brinkman Penalization method is used to compute sound scattering in 3D complex geometry. Sound propagation of monitor/TV is studied. The sound field for monitor/TV is simulated by applying Brinkman Penalization method to Linearized Euler Equation. Solid Structure and ambient air are represented as penalty terms in Linearized Euler Equation.

ON THE SYNGE'S THEOREM FOR COMPLEX FINSLER MANIFOLDS

  • Won, Dae-Yeon
    • Bulletin of the Korean Mathematical Society
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    • v.41 no.1
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    • pp.137-145
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    • 2004
  • In [13], we developed a theory of complex Finsler manifolds to investigate the global geometry of complex Finsler manifolds. There we proved a version of Bonnet-Myers' theorem for complex Finsler manifolds with a certain condition on the Finsler metric which is a generalization of the Kahler condition for the Hermitian metric. In this paper, we show that if the holomorphic sectional curvature of M is ${\geq}\;c^2\;>\;0$, then M is simply connected. This is a generalization of the Synge's theorem in the Riemannian geometry and the Tsukamoto's theorem for Kahler manifolds. The main point of the proof lies in how we can circumvent the convex neighborhood theorem in the Riemannian geometry. A second variation formula of arc length for complex Finsler manifolds is also derived.

Synthesis and Structural Characterization of Five- and Six-Coordinate Cobalt(Ⅱ) Complexes of Tripodal Liand. Tris-(2-benzimidazolylmethyl)amine

  • 라명수;문무신
    • Bulletin of the Korean Chemical Society
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    • v.18 no.4
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    • pp.406-409
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    • 1997
  • The various cobalt(Ⅱ) complexes were synthesized and characterized using tris-(2-benzimidazolylmethyl)amine (ntb) as a ligand where the ntb plays as a tripodal tetradentate ligand to form complexes with a trigonal pyramidal geometry. The complexes have 5 and 6 coordinate cobalt(Ⅱ) ions depending on the additional ligand used. In each complex the additional ligand, chloride anion, or acetate anion occupies the "open" site trans to the apical tertiary nitrogen atom of ntb ligand. Complex 1, [Co(Ⅱ)(ntb)Cl]Cl has a trigonal bipyramidal geometry. This geometry was easily constructed using ntb as a tetradentate ligand and chloride as a monodentate ligand. The complex is isostructural to the corresponding manganese(Ⅱ) complex. Crystal data are as follows: [Co(Ⅱ)(ntb)Cl]Cl·MeOH, 1. triclinic space group P1; a=13.524(2) Å, b=14.037(2) Å, c=17.275(1) Å; α=78.798(9), β=84.159(8)°, γ=65.504(9)°; V=2929.6(6) Å3; Z=4; R1=0.0715, wR2=0.1461 for reflections of I > 2σ(I). Six coordinate complex 2 [Co(ntb)(OAc)](OAc) was synthesized using ntb as a tetradentate ligand and acetate as a bidentate chelating ligand.

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Code Development of Automatic Mesh Generation for Finite Element Method Using Delaunay Triangulation Method (Delaunay 삼각화에 의한 유한요소 자동 생성 코드 개발에 관한 연구)

  • Park Pyong-Ho;Sah Jong-Youb
    • 한국전산유체공학회:학술대회논문집
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    • pp.111-117
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    • 1996
  • The Delaunay triangulation technique was tested for complicated shapes of computational domain. While a simple geometry, both in topology and in geometry, was discretized well into triangular elements. a complex geometry often failed in triangularization. A complex geometry should be devided into smaller sub-domains whose shape is simple both topologically and geometrically. The present study developed the data structures not only for relationships among neibering elements but also for shape information, and coupled these into the Delaunay triangulation technique. This approach was able to enhance greatly the reliability of triangularization specially in complicated shapes of computational domains. The GUI (Graphic User Interface) and OOP (Object-Oriented Programming) were used in order to develop the user-friendly and efficient computer code.

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Material structure generation of concrete and its further usage in numerical simulations

  • Husek, Martin;Kala, Jiri
    • Structural Engineering and Mechanics
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    • v.68 no.3
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    • pp.335-344
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    • 2018
  • The execution of an experiment is a complex affair. It includes the preparation of test specimens, the measurement process itself and also the evaluation of the experiment as such. Financial requirements can differ significantly. In contrast, the cost of numerical simulations can be negligible, but what is the credibility of a simulated experiment? Discussions frequently arise concerning the methodology used in simulations, and particularly over the geometric model used. Simplification, rounding or the complete omission of details are frequent reasons for differences that occur between simulation results and the results of executed experiments. However, the creation of a very complex geometry, perhaps all the way down to the resolution of the very structure of the material, can be complicated. The subject of the article is therefore a means of creating the material structure of concrete contained in a test specimen. Because a complex approach is taken right from the very start of the numerical simulation, maximum agreement with experimental results can be achieved. With regard to the automation of the process described, countless material structures can be generated and randomly produced samples simulated in this way. Subsequently, a certain degree of randomness can be observed in the results obtained, e.g., the shape of the failure - just as is the case with experiments. The first part of the article presents a description of a complex approach to the creation of a geometry representing real concrete test specimens. The second part presents a practical application in which the numerical simulation of the compressive testing of concrete is executed using the generated geometry.

REAL HYPERSURFACES SATISFYING ${\nabla}_{\xi}S$ = 0 OF A COMPLEX SPACE FORM

  • Kang, Eun-Hee;Ki, U-Hang
    • Bulletin of the Korean Mathematical Society
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    • v.35 no.4
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    • pp.819-835
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    • 1998
  • The main purpose of this paper is to prove that if a real hypersurfaces M of a complex space form satisfies ${\nabla}_{\xi}S$=0 and $S{\xi}=\sigma\xi$ for some constant on $\sigma$ on M, then the structure vector field $\xi$ is principal, where S denotes the Ricci tensors of M.

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Design Principles of Fractal Geometry as Complex System (복잡계 구조로서 프랙탈 기하학의 조형원리)

  • Lim, Eun-Young
    • Proceedings of the Korean Institute of Interior Design Conference
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    • pp.195-196
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    • 2004
  • Fractal geometry based upon the latest complex theory shows different features of design pattern quite different from the past. It is not yet sure which kind of effects it would bring about in the future, we think that it would help to create various spaces and organic design vision. Therefore we will look into the significances and adaptabilities in space design by studying fractal design principles of today's new model in space design

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Analysis on the Surface Accuracy in according to Geometry of End Mill (엔드밀의 형상에 따른 가공정밀도 해석)

  • 고성림;이상규;김용현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1001-1004
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    • 2000
  • As tools for machining precision components, end mills and ball end mills are widely used. For the end mills have longer cylindrical shape comparing diameter, liable to deflect and induce deterioration of surface roughness. Tool geometry parameters and cutting process have complex relations with each other. So, It is hard to determine hew to select optimal tool geometry. So, to improve the stiffness, relationship between cutting process and tool geometry must be studied. In this study, relations between grinding wheel geometry, setting condition and tool geometry are revealed. For the purpose of studying relations between each parameter, the equivalent diameter of tool has been calculated assuming tool as a simple beam. By the various cutting simulations and experiments, tool geometry and cutting process has been studied.

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