The presence of coherent structures in turbulent shear flows and their importance in enhancing mixing and entrainment of chemical species has been established in recent years through extensive experimental and numerical studies. When non-premixed combustion is considered, the combustion processes could be enhanced by enhancing the fuel-air mixing and entrainment processes associated with these large coherent structures. In recent experimental studies, the entrainment characteristics of jets with different cross sections were studied, and it was determined that an elliptical jet with a certain cross-sectional shape was more efficient in entraining fluid than a circular jet with the same jet area. This increase was attributed to the complex self-induction process and the subsequent three-dimensional deformation of the elliptical vortex ring during its propagation. To understand the complex flow features associated with elliptical jets with and without heat release, a numerical study was undertaken. A new three-dimensional hybrid Navier-Stokes code was developed using spectral techniques and compact schemes to study the spatial evolution of elliptical jets. The simulation code is now ready for carrying out a detailed study of the effect of jet geometry on the mixing and combustion processes. Keywords: Direct numerical simulations; Elliptical jet flow; Compact schemes; Spectral methods; Turbulent flows; Reacting flows; Heat release; Combustion.

Contents: Description of accurate boundary conditions for the simulation of reactive flows. Parallel direct numerical simulation of turbulent reactive flow. Flame-wall interaction and heat flux modelling in turbulent channel flow. A numerical study of laminar flame wall interaction with detailed chemistry: wall temperature effects. Modeling and simulation of turbulent flame kernel evolution. Experimental and theoretical analysis of flame surface density modelling for premixed turbulent combustion. Gradient and counter-gradient transport in turbulent premixed flames. Direct numerical simulation of turbulent flames with complex chemical kinetics. Effects of curvature and unsteadiness in diffusion flames. Implications for turbulent diffusion combustion. Numerical simulations of autoignition in turbulent mixing flows. Stabilization processes of diffusion flames. References.