When moving discontinuities in solids need to be simulated, standard finite element (FE) procedures usually attain low accuracy because of spurious oscillations appearing behind the discontinuity fronts. To assure an accurate tracking of traveling stress waves in heterogeneous media, we propose here a flux-corrected transport (FCT) technique for structured as well as unstructured space discreti...

We introduce a novel cut-cell Cartesian grid method that preserves the spectral properties of convection and diffusion. That is, convection is discretised by a skewsymmetric operator and diffusion is approximated by a symmetric positive-definite coefficient matrix. Such a symmetry-preserving discretisation of the Navier-Stokes equations is stable on any grid, and conserves the mass, momentum an...

The net rate of metabolic processes in cells depends on the competition between the reactivity of the system and the diffusive flow of substrates to the reaction center (Weisz, 1973). For instance, aerobic metabolism depends on the kinetic properties of the mitochondrial enzymes involved in oxidative phosphorylation and on the diffusive flux of substrates such as ADP to the mitochondria. Howeve...

Of the *240 9 10 mol year of biogenic silica (bSi) produced by diatoms and other silicifying organisms, only roughly 3%–4% escapes dissolution to be permanently buried. At the global scale, how, where and why bSi is preserved in sediment is not well understood. To help address this, I compile 6245 porewater dissolved Si concentrations from 453 sediment cores, to derive the concentration gradien...

Abstract. We obtain macroscopic isothermal thermodynamic transformations by space-time scalings of a microscopic Hamiltonian dynamics in contact with a heat bath. The microscopic dynamics is given by a chain of anharmonic oscillators subject to a varying tension (external force) and the contact with the heat bath is modeled by independent Langevin dynamics acting on each particle. After a diffu...

We establish a notion of random entropy solution for degenerate fractional conservation laws incorporating randomness in the initial data, convective flux, and diffusive flux. In order to quantify uncertainty, we design multilevel Monte Carlo finite difference method (MLMC-FDM) approximate ensemble average solutions. Furthermore, analyze convergence rates MLMC-FDM compare them with deterministi...

A sequence of two- and three-dimensional simulations are conducted for the double-diffusive convection (DDC) flows in diffusive regime subjected to an imposed shear. For a wide range control parameters, sufficiently strong perturbation conductive initial state, staircase-like structures spontaneously develop, with relatively well-mixed layers separated by sharp interfaces enhanced scalar gradie...

[1] Most estimates of diffusive flux (F) of methane (CH4) and carbon dioxide (CO2) from lakes are based on single-point flux chamber measurements or on piston velocity (k) modeled from wind speed and single-point measurements of surface water gas concentrations (Caq). We analyzed spatial variability of F of CH4 and CO2, as well as Caq and k in 22 European lakes during late summer. F and k were ...