The basic character of diffusive transport in a magnetised plasma depends on what kind of transport is modelled. ExB turbulence under drift ordering has special characteristics: it is nearly incompressible, and it cannot lead to magnetic flux diffusion if it is electrostatic. The ExB velocity is also related to the Poynting energy flux. Under quasineutral dynamics, electric fields are not cause...

The Arctic Ocean thermohaline stratification frequently exhibits a staircase structure overlying the Atlantic Water Layer that can be attributed to the diffusive form of double-diffusive convection. The staircase consists of multiple layers of O(1) m in thickness separated by sharp interfaces, across which temperature and salinity change abruptly. Through a detailed analysis of Ice-Tethered Pro...

Previous, linear analysis has suggested that observations of interleaving, quasihorizontal layers in the equatorial oceans may be explained by double-diffusive or inertial instability. Here we describe an idealized, two-dimensional, numerical investigation of the nonlinear development of these instabilities, focusing almost exclusively on the double-diffusive case. We consider the mechanisms fo...

The convergence of advective and diffusive buoyancy flux must match the air-sea buoyancy flux between two outcropping isopycnals. This leads to a diagnostic framework for water mass transformation in which a myriad of different processes can be incorporated under a unifying balance. We review how the diapycnal advection due to ubiquitous mixed layer entrainment can be included in this framework...

It is shown that the standard expression for the diffusive flux in a semiconductor can be transformed to the flux from the Einstein Smoluchowski equation after making use of the ”Einstein identities”. Later, it is possible to use a transformation introduced in: S.Piekarski, ”On the modified Fick law and its potential applications” (J.Tech.Phys.,44,2,125-131,2003). In this formalism, it is possi...

Abstract. A general procedure to construct a class of simple and efficient high resolution Total Variation Diminishing (TVD) schemes for non-linear hyperbolic conservation laws by introducing anti-diffusive terms with the flux limiters is presented. In the present work the numerical flux function for space discretization is constructed as a combination of numerical flux function of any entropy ...

An approach to integrate transport equations with fluxes being complex non-linear functions of physical parameters and their gradients, as it is predicted by theoretical models for micro-instabilities in plasma, is proposed. This approach operates without any splitting of the flux on diffusive and convective components often involved in transport calculations. As an example, computations of the...

The family of nonlinear weighted flux methods for solving the transport equation is derived for 2D Cartesian geometry. A linear polynomial weight is considered. An asymptotic diffusion limit analysis is performed on the discretized method. The analysis reveals conditions on the weight necessary for an accurate approximation of the diffusion equation. As a result, we developed a new weighted flu...

where ρ [ kg m3 ] is the mass density of the phase α; ε [1] is the volume fraction occupied by the phase α; q [ m s ] is Darcy’s velocity of the phase α; ω i [1] is the mass fraction of component i in the α phase; Ji [ kg m2s ] is the flux vector representing the diffusive flux of component i in the phase α; f i [ 1 s ] is the source of component i in the phase α; ei [ 1 s ] is the gain of mass...

Comparatively little attention has been given to multicomponent diffusion effects in lean hydrogen-air flames, in spite of the importance of these flames in safety and their potential importance to future energy technologies. Prior direct numerical simulations either have considered only the mixture-averaged transport model, or have been limited to stabilized flames that do not exhibit the ther...