At the smallest length scales, conductivity measurements include a contribution from salinity fluctuations in the inertial–convective and viscous–diffusive ranges of the turbulent scalar variance spectrum. Interpreting these measurements is complicated because conductivity is a compound quantity of both temperature and salinity. Accurate estimates of the dissipation rate of salinity variance xS...

A common approach for parameterising eddy transport of passive tracers by mesoscale eddies in the ocean is invoking a tensor. The symmetric part this tensor, diffusion quantifies diffusive tracer transport. Recent studies have diagnosed opposite-signed eigenvalues (diffusivities) tensor from eddy-resolving simulations, while all current parameterisations implement only positive diffusivities. F...

0017-9310/$ see front matter 2010 Elsevier Ltd. A doi:10.1016/j.ijheatmasstransfer.2010.01.017 * Corresponding author. Tel.: +1 775 784 4986; fax E-mail addresses: [email protected] (F. Su Tyler), [email protected] (A.E. Childress). A fully coupled two-dimensional, numerical model that evaluates, for the first time, the effects of doublediffusive convection in the thermal performance and stabi...

We study the large-time behaviour of the solutions u of the evolution equation involving nonlinear diffusion and gradient absorption ∂tu−∆pu+ |∇u| q = 0. We consider the problem posed for x ∈ R and t > 0 with non-negative and compactly supported initial data. We take the exponent p > 2 which corresponds to slow p-Laplacian diffusion, and the exponent q in the superlinear range 1 < q < p − 1. In...

Cytoplasmic streaming (CPS) is well known to assist the movement of nutrients, organelles and genetic material by transporting all of the cytoplasmic contents of a cell. CPS is generated by motility organelles that are driven by motor proteins near a membrane surface, where the CPS has been found to have a flat velocity profile in the flow field according to the sliding theory. There is a consi...

Parameterizations of the eddy-induced velocity that advects tracers in addition to the Eulerian mean flow are traditionally expressed as a downgradient Fickian diffusion of either isopycnal layer thickness or large-scale potential vorticity (PV). There is an ongoing debate on which of the two closures is better and how the spatial dependence of the eddy diffusivity should look like. To increase...

In many developmental systems, spatial pattern arises from morphogen gradients, which provide positional information for cells to determine their fate. Typically, diffusion is thought to be the mechanism responsible for building a morphogen gradient. An alternative mechanism is investigated here. Using mathematical modeling, we demonstrate how a non-diffusive morphogen concentration gradient ca...

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...

The effect of steady strain on the transient autoignition of n-heptane at high pressures is studied numerically with detailed chemistry and transport in a counterflow configuration. Skeletal and reduced n-heptane mechanisms are developed and validated against experiments over a range of pressure and stoichiometries. Two configurations are investigated using the skeletal mechanism. First, the ef...