Effective Diahaline Diffusivities in Estuaries

Calculating effective diffusivities in the limit of vanishing molecular diffusion

In this paper we study the problem of the numerical calculation (by Monte Carlo Methods) of the effective diffusivity for a particle moving in a periodic divergent-free velocity filed, in the limit of vanishing molecular diffusion. In this limit traditional numerical methods typically fail, since they do not represent accurately the geometry of the underlying deterministic dynamics. We propose ...

Monte Carlo calculation of effective diffusivities in two- and three-dimensional heterogeneous materials of variable structure.

Turbulence in a sheared , salt - fingering - favorable environment : 1 Anisotropy and effective diffusivities

5 Direct numerical simulations (DNS) of a shear layer with salt-fingering-favorable stratifica6 tion have been performed for different Richardson numbers Ri and density ratios Rρ. When 7 the Richardson number is infinite (unsheared case), the primary instability is square plan8 form salt-fingering, alternating cells of rising and sinking fluid. In the presence of shear, 9 salt-fingering takes t...

Turbulence in a Sheared, Salt-Fingering-Favorable Environment: Anisotropy and Effective Diffusivities

Direct numerical simulations (DNS) of a shear layer with salt-fingering-favorable stratification have been performed for different Richardson numbers Ri and density ratios Rr. In the absence of shear (Ri 5 ‘), the primary instability is square planform salt fingering, alternating cells of rising and sinking fluid. In the presence of shear, salt fingering takes the form of salt sheets, planar re...

Analytical And Numerical Approximation of Effective Diffusivities in The Cytoplasm of Biological Cells

The simulation of the metabolism in mammalian cells becomes a severe problem if spatial distributions must be taken into account. Especially the cytoplsma has a very complex geometric structure which cannot be handled by standard discretization techniques. In the present paper we propose a homogenization technique for computing effective diffusion constants. This is accomplished by using a two-...