A new phenomenological model, the TP (Temperature Phase) model, is presented to carry out optimization calculations for turbulent diffusion combustion in a high-pressure common rail diesel engine. Temperature is the most important parameter in the TP model, which includes two parts: an auto-ignition and a soot model. In the auto-ignition phase, different reaction mechanisms are built for differ...

The paper deals with photosynthetic microorganism growth modelling and simulation in a distributed parameter system. Main result concerns the development and comparison of two modelling frameworks for photo-bioreactor modelling. The first ”classical” approach is based on PDE (reaction-turbulent diffusion system) and finite difference method. The alternative approach is based on random walk mode...

The effect of turbulent electron diffusion from stochastic electron orbits on the stability of low beta fluctuations is considered. A set of coupled self-adjoint equations is derived for the fluctuation potentials and A,,. For the tearing mode, it is shown that stability is obtained for sufficiently large values of the diffusion coefficient, Provided D, 1/n, this implies that a density threshol...

In this paper, we study the effect of MHD turbulence on the dynamics of dust particles in protoplanetary disks. We vary the size of the particles and relate the dust evolution to the turbulent velocity fluctuations. We performed numerical simulations using two Eulerian MHD codes, both based on finite difference techniques: ZEUS– 3D and NIRVANA. These were local shearing box simulations incorpor...

Amajor goal of combustion research is to develop accurate, tractable, predictive models for the phenomena occurring in combustion devices, which predominantly involve turbulent flows. With the focus on gasphase, non-premixed flames, recent progress is reviewed, and the significant remaining challenges facing models of turbulent combustion are examined. The principal challenges are posed by the ...

Atmospheric air pollution turbulent fluxes can be assumed to be proportional to themean concentration gradient. This assumption, alongwith the equation of continuity, leads to the advection-diffusion equation. Moreover, large eddies are able to mix scalar quantities in a manner that is counter to the local gradient. We present a general solution of a two-dimension steady state advection-diffusi...

The eddy-diffusion parameterization of turbulent transport is based on the assumption, often questionable for geophysical flows, of infinitesimal scales of turbulence. In this paper we quantitatively compute what are the consequences of this assumption on the estimates of dispersion for some simple flows with oceanographical scales. We compare the analytical results of two different models, one...

Mixing and transport of a stratifying scalar are investigated at a density interface imbedded in a turbulent shear flow. Steady-state interfacial shear flows are generated in a laboratory water channel for layer Richardson numbers, Ri, between about 1 and 10. The flow field is made optically homogeneous, enabling the use of laser-induced fluorescence with photodiode array imaging to measure the...