  Inter-scale kinetic energy transfer in turbulent flows is accompanied by very
intense and intermittent spatial-temporal fluctuations. Such intermittency is
expected to be particularly prominent in premixed flames, where heat release,
density variations, dilatation, and chemical reactions are localized to spatial
scales that are substantially smaller than scales of large turbulent eddies but
are often larger than or comparable with Kolmogorov length scale. Nevertheless,
intermittency of inter-scale energy transfer and of heat exchange between
internal and kinetic energy in premixed flames has not yet been given due
attention. The present work aims at bridging this knowledge gap. For this
purpose, three-dimensional direct numerical simulation data obtained earlier
from a statistically stationary, planar, one-dimensional lean hydrogen-air
flame propagating in moderately intense turbulence are filtered using cubes of
various widths. Subsequently, Probability Density Functions (PDFs) of various
instantaneous flow characteristics are sampled by processing the filtered
fields of velocity, pressure, density, and their spatial gradients. The sampled
PDFs exhibit long tails, are highly skewed, and are characterized by a large
kurtosis, thus, evidencing significant intermittency of inter-scale energy
transfer and heat exchange between internal and kinetic energy in the flame.
