In order to evaluate transport properties in turbulent premixed flames, a propagating turbulent premixed flame in an incoming homogeneous isotropic turbulence is directly simulated assuming a single-step irreversible Arrhenius-type reaction. To investigate the production of turbulent kinetic energy in the flame region, Favre averaged transport equation of turbulent kinetic energy along streamwi...

Mathematical models have been developed and applied to investigate the composition distributions that arise during steel grade changes in the continuous slab casting processes. Three-dimensional turbulent flow and transient mixing phenomena in the mold and the strand were calculated under conditions corresponding to a sudden change in grade. The composition distribution in the final slab was th...

An effect of sheared large-scale motions on a mean electromotive force in a nonrotating turbulent flow of a conducting fluid is studied. It is demonstrated that in a homogeneous divergence-free turbulent flow the alpha effect does not exist, however a mean magnetic field can be generated even in a nonrotating turbulence with an imposed mean velocity shear due to a "shear-current" effect. A mean...

We determine numerically the parallel, perpendicular, and antisymmetric diffusion coefficients for charged particles propagating in highly turbulent magnetic fields, by means of extensive Monte Carlo simulations. We propose simple expressions, given in terms of a small set of fitting parameters, to account for the diffusion coefficients as functions of magnetic rigidity and turbulence level, an...

We evaluate various molecular tagging velocimetry (MTV) techniques for application in turbulent flows of gases where the smallest length scales must be resolved. We argue that tracer diffusion dictates the use of large complex molecules and discuss a few candidate molecules. The accuracy of MTV is determined by the profile of written lines which widen due to molecular dynamics, including both d...

Turbulent mixing of a passive scalar in fully developed turbulent pipe flow has been investigated by means of a Direct Numerical Simulation (DNS). The scalar is released from a point source located on the centreline of the pipe. The domain size of the concentration field has been chosen large enough to capture the different stages of turbulent mixing. Results are presented for mean concentratio...

The nonlinear coefficients defining the mean electromotive force (i.e., the nonlinear turbulent magnetic diffusion, the nonlinear effective velocity, the nonlinear kappa tensor, etc.) are calculated for an anisotropic turbulence. A particular case of an anisotropic background turbulence (i.e., the turbulence with zero-mean magnetic field) with one preferential direction is considered. It is sho...

Turbulent flows with chemical reactions can be seen in various fields. Therefore, it is important to establish numerical methods to predict turbulent reactive flows. Reynolds-averaged approach is often used for predictions of reactive flows. In this approach, Reynolds-averaged scalar transport equations are solved by using models for a turbulent mass flux and an averaged production rate ...

In shallow turbulent flows such as floods and tsunami vertical mixing tends to smooth out the flow characteristics in cross-sectional direction. The evolution of the average cross-flow characteristics presents considerable interest. We model such flows using the k-ω model of turbulence in the framework of the centre manifold theory. We tested the approach on an artificial diffusion problem for ...

Models of Titan ionospheric chemistry have shown that ion densities depend strongly on the neutral composition. The turbulent diffusion transport conditions, as modeled by eddy coefficients, can spectacularly affect the uncertainty on predicted neutral densities. In order to evaluate the error budget on ion densities predicted by photochemical models, we perform uncertainty propagation of neutr...