In order to characterize the chaotic variations of the cool flame temperature observed during the oxidation of a hydrocarbon at low temperature and under non-homogeneous conditions, we perform multifractal analyses of different measures. In the cool flame localization domain, the singularity spectrum obtained for the visited temperature histogram is comparable to the spectrum deduced from a wavelet transform. In the cool flame propagation domain where the temperature histogram is too narrow to be analyzed, the wavelet transform allows us to prove the multifractal character of the chaos observed. The choice of the parameter value retained to perform the wavelet transform is discussed in detail.
Flame propagation visualization in a spark-ignition engine using laser-induced fluorescence of cool-flame species
