Jean Louis Woukeng

Homogenization of a stochastic nonlinear reaction–diffusion equation with a large reaction term: The almost periodic framework

Abstract Homogenization of a stochastic nonlinear reaction–diffusion equation with a large nonlinear term is considered. Under a general Besicovitch almost periodicity assumption on the coefficients of the equation we prove that the sequence of solutions of the said problem converges in probability towards the solution of a rather different type of equation, namely, the stochastic nonlinear convection–diffusion equation which we explicitly derive in terms of appropriate functionals. We study some particular cases such as the periodic framework, and many others. This is achieved under a suitable generalized concept of Σ -convergence for stochastic processes.

Multiscale homogenization of nonlinear hyperbolic equations with several time scales

Abstract We study the multiscale homogenization of a nonlinear hyperbolic equation in a periodic setting. We obtain an accurate homogenization result. We also show that as the nonlinear term depends on the microscopic time variable, the global homogenized problem thus obtained is a system consisting of two hyperbolic equations. It is also shown that in spite of the presence of several time scales, the global homogenized problem is not a reiterated one.

Homogenization of Nonlinear Stochastic Partial Differential Equations in a General Ergodic Environment

In this article, we show that the concept of sigma-convergence associated to stochastic processes can tackle the homogenization of stochastic partial differential equations. In this regard, the homogenization of a stochastic nonlinear partial differential equation is addressed. Using some deep compactness results such as the Prokhorov and Skorokhod theorems, we prove that the sequence of solutions of this problem converges in probability towards the solution of an equation of the same type. To proceed with, we use the concept of sigma-convergence for stochastic processes, which takes into account both the deterministic and random behaviours of the solutions of the problem.

Periodic homogenization of strongly nonlinear reaction–diffusion equations with large reaction terms

We study in this article the periodic homogenization problem related to a strongly nonlinear reaction–diffusion equation. Owing to the large reaction term, the homogenized equation has a rather quite different form which puts together both the reaction and convection effects. We show in a special case that the homogenized equation is exactly of a convection-diffusion type. This study relies on a suitable version of the well-known two-scale convergence method.

Stability under composition of some classes of functions and applications to homogenization theory

In this letter we show that in contrast to what has been done so far in the deterministic homogenization theory, we can solve nonlinear homogenization problems in a general way by leaning solely on a single assumption. We also show that this assumption is suitable for finding particular solutions (such as almost periodic ones) of some partial differential equations.

Corrector problem in the deterministic homogenization of nonlinear elliptic equations

ABSTRACT We carry out the deterministic homogenization of nonlinear elliptic operators beyond periodicity. To proceed with, we prove the existence of nonlinear correctors in the usual distributional sense. This lays the foundation for the study of regularity results in the nonlinear deterministic homogenization theory beyond the periodic setting.