A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.

A two-point method has recently been demonstrated based on picosecond time-resolved laser-induced fluorescence (PITLIF). This technique is capable of simultaneously monitoring OH time series at two locations, hence allowing the characterization of spatial structures in turbulent flames in addition to their temporal behavior. Several refinements have been made to improve upon the previous one-point instrument. Using a specially designed collection-lens system, off-axis optical aberrations have been effectively minimized in the probe volume. Furthermore, additional electronics has been installed which permit absolute species concentration measurements. As a preliminary study, two-point OH time-series measurements were taken in three standard turbulent non-premixed flames (H3, DLR_A and DLR_B). Two-point statistics, including space-time correlations, spatial autocorrelation functions and integral length scales were computed to help elucidate the flame structure and turbulence-chemistry interactions.