This paper describes an analysis of acoustic wave scattering by turbulent p
remixed flames with moving, convoluted fronts that have random and possibly
fractal characteristics. Such interactions play a role in the characterist
ic unsteadiness observed in turbulent combustion processes. The problem is
posed with an integral formulation of the wave equation and assumes that th
e smallest scales of flame wrinkling are much larger than the acoustic wave
length. Thus, these results apply to high frequency (short wavelength) wave
scattering. Explicit solutions for the spatial and temporal characteristic
s of the scattered field are derived for cases where the characteristics of
the flame surface are Gaussian. These characteristics are investigated for
flames with single, multiple, and continuous (e.g., fractal) scales of wri
nkling. It is shown that the spectral characteristics of the waves scattere
d from weakly corrugated flames are the same as those of the incident frequ
ency shifted spectrum of the flame front position. Thus. these results sugg
est that scattering measurements can provide information about the spectrum
of the flame front position. It is also shown, however, that as the flame
roughness increases, the spectral characteristics of the scattered waves be
come increasingly scrambled relative to those of the flame itself, and thus
, provide less information about the temporal characteristics of the flame'
s movement. The paper closes with a discussion of additional possibilities
for using the integral equation approach used in this paper to assess other
characteristics of acoustic wave-turbulent flame interactions. (C) 2001 by
The Combustion Institute.