  The LES/PDF methodology is applied to the Cambridge/Sandia turbulent
stratified flame series under swirling conditions. The methane/air chemistry is
represented by a 16-species reduced ARM1 mechanism, and the in situ adaptive
tabulation method is adopted to accelerate the chemistry calculation. Effects
of differential diffusion and heat loss through the bluffbody surface are taken
into account. The simulations are conducted for premixed (SwB3), moderately and
highly stratified (SwB7 and SwB11, respectively) cases under swirling
conditions. The results from LES/PDF simulations are compared with experimental
measurements. The computed mean and r.m.s. profiles of velocity, temperature,
equivalence ratio and mass fractions of species are in very good agreement with
the measurements for all three conditions. Scatter plots and conditional means
of species mole fractions and temperature are compared with the experimental
data, where overall good consistency with the measurements is achieved. The
recirculation zones are five times longer than those obtained under
non-swirling conditions. A low-equivalence-ratio high-temperature region near
the bluffbody is not captured in the computation, which is attributed to the
insuffcient entrainment of downstream mixtures into the recirculation zone. The
parametric studies show that the differential diffusion has a negligible effect
on the mean and r.m.s. results, whereas the heat loss has a considerable effect
on the temperature and CO profiles close to the bluffbody.
