Double-diffusion models from a highly-heterogeneous medium

Double-diffusion Models from a Highly-heterogeneous Medium

A distributed microstructure model is obtained by homogenization from an exact micro-model with continuous temperature and flux for heat diffusion through a periodically distributed highly-heterogeneous medium. This composite medium consists of two flow regions separated by a third region which forms the doubly-porous matrix structure. The homogenized system recognizes the multiple scale proces...

Adaptive Double-Diffusion Model and Comparison to a Highly Heterogeneous Micro-Model

Double-diffusion model is used to simulate slightly compressible fluid flow in periodic porous media as a macro-model in place of the original highly heterogeneous micro-model. In this paper, we formulate an adaptive two-grid numerical finite element discretization of the double-diffusion system and perform a comparison between the microand macro-model. Our numerical results show that the micro...

Effective medium approach for heterogeneous reaction-diffusion media.

An effective medium theory that can be used to calculate effective diffusion and reaction rate coefficients in random heterogeneous reaction-diffusion systems is described. The predictions of the theory are compared with simulations of spatially distributed media with different types of heterogeneity. The magnitude of the front velocity in bistable media is used to gauge the accuracy of the the...

Experimental Analysis of a Vertical, Double-Effect Diffusion Solar Still

Homogenization of one phase flow in a highly heterogeneous porous medium including a thin layer

In this work we consider a model problem describing one phase flow through a thin porous layer made of weakly permeable porous blocks separated by thin fissures. The flow is modeled by a linear parabolic equation considered in a bounded 2D domain with high contrast coefficients. The problem involves three small parameters: the first one characterizes the periodicity of the distribution of the b...