  Numerical simulations of a partially-premixed, turbulent jet diffusion flame
stabilised in a hot vitiated co-flow are performed. For auto-igniting flames,
an accurate prediction of flame stabilisation, which depends on a delicate
balance between turbulent transport and chemical kinetics at the flame base,
poses an enormous challenge to conventional turbulent combustion models.
Multiple mapping conditioning/large eddy simulation (MMC-LES), a promising tool
for modelling turbulence-chemistry interactions, has been successfully applied
to simulate a variety of combustion applications involving gaseous, liquid, and
solid fuels. MMC-LES is a full \gls{PDF} method where MMC plays the role of the
mixing model, emulating molecular mixing phenomenon. MMC attempts to produce
accurate molecular mixing by localising mixing in an independent,
composition-like reference space. Due to this enforced localised mixing, a
sparse distribution of stochastic Lagrangian particles for may be used for the
Monte-Carlo simulation of the sub-grid joint-composition PDF equation. In the
present study, we employ MMC-LES to investigate the auto-igniting methane/air
flames of UC Berkeley. A sparse resolution of 1 particle per 10 Eulerian
finite-volume cells is used in this study, which offers much cheaper computing
expenses in comparison to the conventional transported PDF approach. A skeletal
chemical mechanism, based on GRI 3.0, containing 30 species and 184 reactions,
represents the oxidation of methane. The time-scale of molecular mixing is
modelled using the recently published \textit{dyn-aISO} model to assess its
performance in an auto-igniting configuration.

Fluid Dynamics;Computational Physics