• 제목/요약/키워드: boundary condition

검색결과 2,014건 처리시간 0.108초

THE EIGENVALUE PROBLEM AND A WEAKER FORM OF THE PRINCIPLE OF SPATIAL AVERAGING

  • Kwean, Hyuk-Jin
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제9권1호
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    • pp.31-37
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    • 2002
  • In this paper, we find explicitly the eigenvalues and the eigenfunctions of Laplace operator on a triangle domain with a mixed boundary condition. We also show that a weaker form of the principle of spatial averaging holds for this domain under suitable boundary condition.

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NOTE ON LOCAL BOUNDEDNESS FOR WEAK SOLUTIONS OF NEUMANN PROBLEM FOR SECOND-ORDER ELLIPTIC EQUATIONS

  • KIM, SEICK
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제19권2호
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    • pp.189-195
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    • 2015
  • The goal of this note is to provide a detailed proof for local boundedness estimate near the boundary for weak solutions for second order elliptic equations with bounded measurable coefficients subject to Neumann boundary condition.

A Dynamic Method for Boundary Conditions in Lattice Boltzmann method

  • 서용권;강금분;강상모
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2797-2802
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    • 2007
  • It has been confirmed that implementation of the no-slip boundary conditions for the lattice-Boltzmann method play an important role in the overall accuracy of the numerical solutions as well as the stability of the solution procedure. We in this paper propose a new algorithm, i.e. the method of the dynamic boundary condition for no-slip boundary condition. The distribution functions on the wall along each of the links across the physical boundary are assumed to be composed of equilibrium and nonequilibrium parts which inherit the idea of Guo's extrapolation method. In the proposed algorithm, we apply a dynamic equation to reflect the computational slip velocity error occurred on the actual wall boundary to the correction; the calculated slip velocity error dynamically corrects the fictitious velocity on the wall nodes which are subsequently employed to the computation of equilibrium distribution functions on the wall nodes. Along with the dynamic selfcorrecting process, the calculation efficiently approaches the steady state. Numerical results show that the dynamic boundary method is featured with high accuracy and simplicity.

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지반조건이 현장 타설 말뚝 선단부의 동적 경계조건에 미치는 영향 (Effects of Soil Conditions on the Vibratory Motion of Drilled Shaft)

  • 이병식;이원구
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 봄 학술발표회 논문집
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    • pp.159-166
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    • 2000
  • Non-destructive out-hole tests, impact-echo and impact-response are widely applied to evaluate integrity of drilled shafts. In these tests, vibratory motions of drilled shafts are interpreted, which induced by impacts on the shaft head. In applying the tests to evaluating integrity of shaft, it has been attended whether the tests have resolutions enough to distinguish existence of slime at between the shaft end and a bearing soil deposit. To distinguish existence of slime by tests, modes of shaft vibrations need to be reasonably interpreted, which generally vary according to a shaft boundary condition such as, a free-free or a free-fixed condition. The boundary condition of a shaft is, however, found to be significantly affected by stiffness of soil deposits around shaft as well as penetration depths of shaft into a bearing soil deposit. Thus, these effects on the boundary condition of a shaft should be considered reasonably in interpreting test results to decide the existence of slime. To investigate the effects, in this study, vibratory motions of shafts constructed in various soil conditions and end penetration depths are examined analytically. Based on the studies, variations of boundary condition are characterized in terms of soil stiffness contrast between a shaft perimeter and a shaft end, and also the ratio of a penetration depth to a shaft length. The results can be applied to verify the applicability of tests to identify the slime.

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사각격자체계 수치모델에서의 경사면 처리기법에 관하여 (On Reasonable Boundary Condition for Inclined Seabed/Structure in Case of the Numerical Model with Quadrilateral Mesh System)

  • 허동수;이우동;배기성
    • 대한토목학회논문집
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    • 제28권5B호
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    • pp.591-594
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    • 2008
  • 본 연구에서는 사각격자체계를 이용하는 수치해석기법을 대상으로 격자내에 생성되는 경사면의 합리적인 처리 및 경계조건을 검토하기 위하여 사각격자내에 존재하는 불투과성 및 투과성구조물의 경사면에 대한 새로운 처리기법과 경계조건을 제안한 후, 파 구조물 해저지반/해빈의 상호간섭을 직접 해석할 수 있는 3D-수치모델(LES-WASS-3D; 허와 이, 2007)을 이용하여 수치계산을 실시하였다. 이로부터 얻어진 계산결과와 종래의 계단식 격자구성을 이용한 수치해석결과를 비교 검토하여 제안한 사각격자내의 경사면 처리기법에 대한 타당성을 검증하였다.

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