scholarly journals Convergence Results for the Double-Diffusion Perturbation Equations

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 67
Author(s):  
Jincheng Shi ◽  
Shiguang Luo

We study the structural stability for the double-diffusion perturbation equations. Using the a priori bounds, the convergence results on the reaction boundary coefficients k1, k2 and the Lewis coefficient Le could be obtained with the aid of some Poincare´ inequalities. The results showed that the structural stability is valid for the the double-diffusion perturbation equations with reaction boundary conditions. Our results can be seen as a version of symmetry in inequality for studying the structural stability.

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Yuanfei Li

In this paper, the initial boundary value problem for the two-dimensional large-scale primitive equations of large-scale oceanic motion in geophysics is considered, which are fundamental models for weather prediction. By establishing rigorous a priori bounds with coefficients and deriving some useful inequalities, the convergence result for the boundary conditions is obtained.


Author(s):  
Björn Augner ◽  
Dieter Bothe

AbstractWe investigate limit models resulting from a dimensional analysis of quite general heterogeneous catalysis models with fast sorption (i.e. exchange of mass between the bulk phase and the catalytic surface of a reactor) and fast surface chemistry for a prototypical chemical reactor. For the resulting reaction–diffusion systems with linear boundary conditions on the normal mass fluxes, but at the same time nonlinear boundary conditions on the concentrations itself, we provide analytic properties such as local-in-time well-posedness, positivity, a priori bounds and comment on steps towards global existence of strong solutions in the class $$\mathrm {W}^{(1,2)}_p(J \times \Omega ; {{\,\mathrm{{\mathbb {R}}}\,}}^N)$$ W p ( 1 , 2 ) ( J × Ω ; R N ) , and of classical solutions in the Hölder class $$\mathrm {C}^{(1+\alpha , 2 + 2\alpha )}({\overline{J}} \times {\overline{\Omega }}; {{\,\mathrm{{\mathbb {R}}}\,}}^N)$$ C ( 1 + α , 2 + 2 α ) ( J ¯ × Ω ¯ ; R N ) . Exploiting that the model is based on thermodynamic principles, we further show a priori bounds related to mass conservation and the entropy principle.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Jincheng Shi ◽  
Yan Liu

AbstractThe structural stability for the Forchheimer fluid interfacing with a Darcy fluid in a bounded region in $\mathbb{R}^{3}$ R 3 was studied. We assumed that the nonlinear fluid was governed by the Forchheimer equations in $\Omega _{1}$ Ω 1 , while in $\Omega _{2}$ Ω 2 , we supposed that the flow satisfies the Darcy equations. With the aid of some useful a priori bounds, we were able to demonstrate the continuous dependence results for the Forchheimer coefficient λ.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Yuanfei Li ◽  
Shuanghu Zhang ◽  
Changhao Lin

AbstractA priori bounds were derived for the flow in a bounded domain for the viscous-porous interfacing fluids. We assumed that the viscous fluid was slow in $\Omega _{1}$ Ω 1 , which was governed by the Boussinesq equations. For a porous medium in $\Omega _{2}$ Ω 2 , we supposed that the flow satisfied the Darcy equations. With the aid of these a priori bounds we were able to demonstrate the result of the continuous dependence type for the Boussinesq coefficient λ. Following the method of a first-order differential inequality, we can further obtain the result that the solution depends continuously on the interface boundary coefficient α. These results showed that the structural stability is valid for the interfacing problem.


2000 ◽  
Vol 7 (4) ◽  
pp. 677-688 ◽  
Author(s):  
P. Kelevedjiev ◽  
N. Popivanov

Abstract The existence results obtained for the Dirichlet and mixed BVPs for the equation x ″ = f (t, x, x′) are extended to BVPs with full nonlinear conditions. The proofs are based on the theorem of Granas, Guenther and Lee, while barrier strips are used to obtain a priori bounds for solutions.


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