Pockets in turbulent premixed flames

We address in this paper the problem of pocket formation in turbulent premi xed flames. Pockets of unburnt gases inside the burnt gases, or of burnt ga ses inside unburnt gases have been observed in experiments, usually in tomo graphic cuts of a three-dimensional flame. We study here two effects (range of length scales and different time correlations) controlling the number a nd type of pockets created, on the basis of a two-dimensional numerical stu dy of the thermal-diffusive model subjected to an external turbulent forcin g (i.e. we neglect the retroaction of the flame on the flow field).