• Title/Summary/Keyword: Fixed boundary condition

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TWO EXAMPLES OF LEFSCHETZ FIXED POINT FORMULA WITH RESPECT TO SOME BOUNDARY CONDITIONS

  • Yoonweon Lee
    • Journal of the Chungcheong Mathematical Society
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    • v.37 no.1
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    • pp.1-17
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    • 2024
  • The boundary conditions $\tilde{P}_0$ and $\tilde{P}_1$ were introduced in [5] by using the Hodge decomposition on the de Rham complex. In [6] the Atiyah-Bott-Lefschetz type fixed point formulas were proved on a compact Riemannian manifold with boundary for some special type of smooth functions by using these two boundary conditions. In this paper we slightly extend the result of [6] and give two examples showing these fixed point theorems.

Turbulent Flow Simulations on 2-Dimensional Ground Effect Part II. Study on the Effects of Ground Boundary Conditions (2차원 지면효과에 대한 난류 유동장 해석 Part II. 지면경계 조건의 영향에 대한 연구)

  • Kim, Yoon-Sik;Lee, Jae-Eun;Kim, Eu-Gene;Kwon, Jang-Hyuk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.8
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    • pp.670-676
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    • 2007
  • A comparative study on ground boundary conditions for the airfoil in ground effect has been carried out. The objective of the present study is to clarify effects of the ground boundary conditions so that it will be helpful to analyse results of wind tunnel tests using the fixed ground board or the image method. A low Mach number preconditioned Navier-Stokes solver using the overlap grid method has been applied. It has been turned out that results with the symmetric boundary condition are almost the same to those with the moving boundary condition. Results with the fixed ground boundary show discrepancy to those with the moving boundary condition when flow separation on the ground board takes place.

FRACTIONAL DIFFERENTIAL EQUATIONS WITH NONLOCAL BOUNDARY CONDITIONS

  • Soenjaya, Agus L.
    • Communications of the Korean Mathematical Society
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    • v.37 no.2
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    • pp.497-502
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    • 2022
  • Existence and uniqueness for fractional differential equations satisfying a general nonlocal initial or boundary condition are proven by means of Schauder's fixed point theorem. The nonlocal condition is given as an integral with respect to a signed measure, and includes the standard initial value condition and multi-point boundary value condition.

EXISTENCE OF POSITIVE SOLUTIONS FOR THE SECOND ORDER DIFFERENTIAL SYSTEMS WITH STRONGLY COUPLED INTEGRAL BOUNDARY CONDITIONS

  • Lee, Eun Kyoung
    • East Asian mathematical journal
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    • v.34 no.5
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    • pp.651-660
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    • 2018
  • This paper concerned the existence of positive solutions to the second order differential systems with strongly coupled integral boundary value conditions. By using Krasnoselskii fixed point theorem, we prove the existence of positive solutions according to the parameters under the proper nonlinear growth conditions.

On the Reconstruction of Pinwise Flux Distribution Using Several Types of Boundary Conditions

  • Park, C. J.;Kim, Y. H.;N. Z. Cho
    • Nuclear Engineering and Technology
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    • v.28 no.3
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    • pp.311-319
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    • 1996
  • We reconstruct the assembly pinwise flux using several types of boundary conditions and confirm that the reconstructed fluxes are the same with the reference flux if the boundary condition is exact. We test EPRI-9R benchmark problem with four boundary conditions, such as Dirichlet boundary condition, Neumann boundary condition, homogeneous mixed boundary condition (albedo type), and inhomogeneous mixed boundary condition. We also test reconstruction of the pinwise flux from nodal values, specifically from the AFEN [1, 2] results. From the nodal flux distribution we obtain surface flux and surface current distributions, which can be used to construct various types of boundary conditions. The result show that the Neumann boundary condition cannot be used for iterative schemes because of its ill-conditioning problem and that the other three boundary conditions give similar accuracy. The Dirichlet boundary condition requires the shortest computing time. The inhomogeneous mixed boundary condition requires only slightly longer computing time than the Dirichlet boundary condition, so that it could also be an alternative. In contrast to the fixed-source type problem resulting from the Dirichlet, Neumann, inhomogeneous mixed boundary conditions, the homogeneous mixed boundary condition constitutes an eigenvalue problem and requires longest computing time among the three (Dirichlet, inhomogeneous mixed, homogeneous mixed) boundary condition problems.

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POSITIVE SOLUTIONS OF SUPERLINEAR AND SUBLINEAR BOUNDARY VALUE PROBLEMS

  • Gatica, Juan A.;Kim, Yun-Ho
    • Korean Journal of Mathematics
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    • v.25 no.1
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    • pp.37-43
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    • 2017
  • We study the existence of positive solutions of second order nonlinear separated boundary value problems of superlinear as well as sublinear type without imposing monotonicity restrictions on the problem. The type of problem investigated cannot be analyzed using the linearization about the trivial solution because either it does not exist (the sublinear case) or is trivial (the superlinear case). The results follow from a known fixed point theorem by noticing that the concavity of the solutions provides an important condition for the applicability of the fixed point result.