3. Turbulent Combustion

1. Introduction. Like the proverbial elephant, turbulent combustion exhibits so many different aspects that two investigators, chosen at random from the set of all investigators examining the subject, will with high probability disagree entirely about its general characteristics. For example, few will know the full definitions of all of the terms “k-ϵ modelling,” “strange attractor,” “Favre average,” “conserved scalar,” “Kolmogorov scale,” “functional differentiation,” “coherent structure,” “large-eddy Damköhler number,” “random vortex,” “spectral transfer,” “intermittency” and “age theory.” Almost all of the investigators will consider at least one of the items in this sequence to be practically irrelevant to turbulent combustion. Yet, for each of the items there likely exist investigators who would identify that item as the central aspect of the subject. Turbulent combustion has now become so multifaceted that no one has the background necessary to give a complete and impartial review of it. Therefore the reader must prepare himself for an incomplete and somewhat biased review.