On Convergence of Difference Schemes for IBVP for Quasilinear Parabolic Equations with Generalized Solutions

2014 ◽  
Vol 14 (3) ◽  
pp. 361-371 ◽  
Author(s):  
Piotr Matus

Abstract.We construct an usual linearized difference scheme for initial boundary value problems (IBVP) for one-dimensional quasilinear parabolic equations with generalized solutions. The uniform parabolicity condition $0<k_1\le k(u) \le k_2$ is assumed to be fulfilled for the sign alternating solution $u(x,t) \in \bar{D}(u)$ only in the domain of exact solution values (unbounded non-linearity). On the basis of new corollaries of the maximum principle, we establish not only two-sided estimates for the approximate solution y but its belonging to the domain of exact solution values. We assume that the solution is continuous and its first derivative $\frac{\partial u}{\partial x}$ has discontinuity of the first kind in the neighborhood of the finite number of discontinuity lines. An existence of time derivative in any sense is not assumed. We prove convergence of the approximate solution to the generalized solution of the differential problem in the grid norm L2.

2020 ◽  
Vol 20 (4) ◽  
pp. 695-707 ◽  
Author(s):  
Piotr Matus ◽  
Dmitriy Poliakov ◽  
Le Minh Hieu

AbstractFor Dirichlet initial boundary value problem (IBVP) for two-dimensional quasilinear parabolic equations with mixed derivatives monotone linearized difference scheme is constructed. The ellipticity conditionsc_{1}\sum_{\alpha=1}^{2}\xi_{\alpha}^{2}\leq\sum_{\alpha,\beta=1}^{2}k_{\alpha% \beta}(u)\xi_{\alpha}\xi_{\beta}\leq c_{2}\sum_{\alpha=1}^{2}\xi_{\alpha}^{2}are assumed to be fulfilled for the sign alternating solution {u(\mathbf{x},t)\in\bar{D}(u)} only in the domain of exact solution values (unbounded nonlinearity). On the basis of the proved new corollaries of the maximum principle, not only two-sided estimates for the approximate solution y but also its belonging to the domain of exact solution values are established. We assume that the solution is continuous and its first derivatives {\frac{\partial u}{\partial x_{i}}} have discontinuities of the first kind in the neighborhood of the finite number of discontinuity lines. No smoothness of the time derivative is assumed. The convergence of an approximate solution to a generalized solution of a differential problem in the grid norm {L_{2}} is proved.


Author(s):  
John E. Lavery

AbstractA method for solving quasilinear parabolic equations of the typesthat differs radically from previously known methods is proposed. For each initial-boundary-value problem of one of these types that has boundary conditions of the first kind (second kind), a conjugate initial-boundary-value problem of the other type that has boundary conditions of the second kind (first kind) is defined. Based on the relations connecting the solutions of a pair of conjugate problems, a series of parabolic equations with constant coefficients that do not change step to step is constructed. The method proposed consists in calculating the solutions of the equations of this series. It is shown to have linear convergence. Results of a series of numerical experiments in a finite-difference setting show that one particular implementation of the proposed method has a smaller domain of convergence than Newton's method but that it sometimes converges faster within that domain.


2008 ◽  
Vol 45 (2) ◽  
pp. 285-300
Author(s):  
László Simon ◽  
Willi Jäger

We consider initial boundary value problems for second order quasilinear parabolic equations where also the main part contains functional dependence on the unknown function and the equations are not uniformly parabolic. The results are generalizations of that of [10]


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