• Title/Summary/Keyword: Periodic boundary Condition

Search Result 128, Processing Time 0.024 seconds

TIME PERIODIC SOLUTIONS TO A HEAT EQUATION WITH LINEAR FORCING AND BOUNDARY CONDITIONS

  • In-Jee Jeong;Sun-Chul Kim
    • Journal of the Korean Mathematical Society
    • /
    • v.60 no.2
    • /
    • pp.465-477
    • /
    • 2023
  • In this study, we consider a heat equation with a variable-coefficient linear forcing term and a time-periodic boundary condition. Under some decay and smoothness assumptions on the coefficient, we establish the existence and uniqueness of a time-periodic solution satisfying the boundary condition. Furthermore, possible connections to the closed boundary layer equations were discussed. The difficulty with a perturbed leading order coefficient is demonstrated by a simple example.

NONTRIVIAL PERIODIC SOLUTION FOR THE SUPERQUADRATIC PARABOLIC PROBLEM

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
    • /
    • v.17 no.1
    • /
    • pp.53-66
    • /
    • 2009
  • We show the existence of a nontrivial periodic solution for the superquadratic parabolic equation with Dirichlet boundary condition and periodic condition with a superquadratic nonlinear term at infinity which have continuous derivatives. We use the critical point theory on the real Hilbert space $L_2({\Omega}{\times}(0 2{\pi}))$. We also use the variational linking theorem which is a generalization of the mountain pass theorem.

  • PDF

MULTIPLE SOLUTIONS FOR A SUSPENDING BEAM EQUATION AND THE GEOMETRY OF THE MAPPING

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
    • /
    • v.17 no.2
    • /
    • pp.211-218
    • /
    • 2009
  • We investigate the multiple solutions for a suspending beam equation with jumping nonlinearity crossing three eigenvalues, with Dirichlet boundary condition and periodic condition. We show the existence of at least six nontrivial periodic solutions for the equation by using the finite dimensional reduction method and the geometry of the mapping.

  • PDF

LERAY-SCHAUDER DEGREE THEORY APPLIED TO THE PERTURBED PARABOLIC PROBLEM

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
    • /
    • v.17 no.2
    • /
    • pp.219-231
    • /
    • 2009
  • We show the existence of at least four solutions for the perturbed parabolic equation with Dirichlet boundary condition and periodic condition when the nonlinear part cross two eigenvalues of the eigenvalue problem of the Laplace operator with boundary condition. We obtain this result by using the Leray-Schauder degree theory, the finite dimensional reduction method and the geometry of the mapping. The main point is that we restrict ourselves to the real Hilbert space instead of the complex space.

  • PDF

Effect of domain size on flow characteristics in simulating periodic obstacle flow (주기적인 경계조건을 사용하는 수치모사에서 계산영역 크기의 영향)

  • Choi, Choon-Bum;Jang, Yong-Jun;Han, Seok Youn;Kim, Jin-Ho;Yang, Kyung-Soo
    • Proceedings of the KSME Conference
    • /
    • 2008.11b
    • /
    • pp.2477-2482
    • /
    • 2008
  • Effect of computational domain size in simulating of periodic obstacle flow has been investigated for the flow past tube banks. Reynolds number, defined by freestream velocity (U) and cylinder diameter (d), was fixed as 200, and center-to-center distance (P) as 1.5d. In-line square array was considered. Drag coefficient, lift coefficient and Strouhal number were calculated depending on domain size. Circular cylinders were implemented on a Cartesian grid system by using an immersed boundary method. Boundary condition is periodic in both streamwise and lateral directions. Previous studies in literature often use a square domain with a side length of P, which contains only one cylinder. However, this study reveals that size is improper. Especially, RMS values of flow-induced forces are most sensitive to the domain size.

  • PDF

VARIATIONAL APPROACH AND THE NUMBER OF THE NONTRIVIAL PERIODIC SOLUTIONS FOR A CLASS OF THE SYSTEM OF THE NONTRIVIAL SUSPENSION BRIDGE EQUATIONS

  • Jung, Tack-Sun;Choi, Q-Heung
    • The Pure and Applied Mathematics
    • /
    • v.16 no.2
    • /
    • pp.199-212
    • /
    • 2009
  • We investigate the multiplicity of the nontrivial periodic solutions for a class of the system of the nonlinear suspension bridge equations with Dirichlet boundary condition and periodic condition. We show that the system has at least two nontrivial periodic solutions by the abstract version of the critical point theory on the manifold with boundary. We investigate the geometry of the sublevel sets of the corresponding functional of the system and the topology of the sublevel sets. Since the functional is strongly indefinite, we use the notion of the suitable version of the Palais-Smale condition.

  • PDF

A Meshfree procedure for the microscopic analysis of particle-reinforced rubber compounds

  • Wu, C.T.;Koishi, M.
    • Interaction and multiscale mechanics
    • /
    • v.2 no.2
    • /
    • pp.129-151
    • /
    • 2009
  • This paper presents a meshfree procedure using a convex generalized meshfree (GMF) approximation for the large deformation analysis of particle-reinforced rubber compounds on microscopic level. The convex GMF approximation possesses the weak-Kronecker-delta property that guarantees the continuity of displacement across the material interface in the rubber compounds. The convex approximation also ensures the positive mass in the discrete system and is less sensitive to the meshfree nodal support size and integration order effects. In this study, the convex approximation is generated in the GMF method by choosing the positive and monotonic increasing basis function. In order to impose the periodic boundary condition in the unit cell method for the microscopic analysis, a singular kernel is introduced on the periodic boundary nodes in the construction of GMF approximation. The periodic boundary condition is solved by the transformation method in both explicit and implicit analyses. To simulate the interface de-bonding phenomena in the rubber compound, the cohesive interface element method is employed in corporation with meshfree method in this study. Several numerical examples are presented to demonstrate the effectiveness of the proposed numerical procedure in the large deformation analysis.