This article presents a new stabilized finite-element formulation for convective-diffusive heat transfer. A mixed temperature and temperature-flux form is proposed that possesses better stability properties as compared to the classical Galerkin form. The issue of arbitrary combinations of temperature and temperature-flux interpolation functions is addressed. Specifically, the combinations of C ̊...

We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tight-binding model. First, we consider the magnetoconductance of such rings and observe the Aharonov–Bohm effect. We investigate different regimes of the magnetic flux up to the quantum Hall regime, where the Aharonov–Bohm oscillations are suppre...

The flux-corrected-transport paradigm is generalized to finite element schemes based on arbitrary time-stepping. A conservative flux decomposition procedure is proposed for both convective and diffusive terms. Mathematical properties of positivity-preserving schemes are reviewed. A nonoscillatory low-order method is constructed by elimination of negative off-diagonal entries of the discrete tra...

Abstract. We introduce a new computational technique for evolving interfaces, the flux-based level set method. A nonlinear degenerate advection-diffusion level set equation is discretized by a finite volume method using a complementary volume strategy. It enables to solve the problem in an efficient and stable way. Using a flux-based method of characteristics for the advective part and a semi-i...

A mathematical model for nutritional transport in capillary tissues exchange system in thepresence of magnetic field has been studied. In this case, the cell is deformed. Due to concentrationgradients, the dissolved nutrient in substrate diffuses into surrounding tissue. Theanalytical method is based on perturbation technique while the numerical simulation is basedon finite difference scheme. R...

Abstract An analysis based on the law of linear momentum conservation demonstrates unequivocally that mass fraction is scalar whose gradient determines gas diffusion, both molecular and turbulent. It illustrates sizeable errors in previous micrometeorological definitions turbulent flux fluctuations other scalars such as mixing ratio or density. In deference to law, we put forth a new definition...

When a linear transport equation contains two scales, one diffusive and the other non-diffusive, it is natural to use a domain decomposition method which couples the transport equation with a diffusion equation with an interface condition. One such method was introduced by Golse, Jin and Levermore in [11], where an interface condition, which is derived from the conservation of energy density, w...

A method for quantifying the effect of medium composition on the diffusive mass transfer of hydrophobic organic chemicals through thin layers was applied to plant tissue. The method employs two silicone disks, one serving as source and one as sink for a series of PAHs diffusing through thin layers of water, potato tissue, and carrot tissue. Naphthalene, phenanthrene, anthracene, and fluoranthen...

A novel methodology for the simulation of 2D thermohaline double diffusive processes, driven by heterogeneous temperature and concentration fields in variable-density saturated porous media, is presented. The stream function is used to describe the flow field and it is defined in terms of mass flux. The partial differential equations governing system is given by the mass conservation equation o...

With the help of diffusive samplers spatial distribution of air pollutants can be assessed and these samplers are therefore a sound completion to continuous monitors. Diffusive sampler networks can be run easily over longer time periods and are an effective tool in air quality management. In the framework of the Swiss Project " Airo Puro " in 6 Central American countries, the diffusive sampling...