Abstract: The random vortex method is used to model turbulent flow and premixed combustion in a 2-D sudden expansion channel. The averaged and instantaneous velocity fields are presented. In contrast with averaged velocity field, more than one large-scale vortexes appear in instantaneous velocity field. Owing to the interaction between these large-scale vortexes, the length of recirculating-flow region changes periodically about the averaged value. The calculation of premixed combustion shows that, these large-scale vortex structures play an important role in the distribution of flame front in the flow field.

Key words: turbulent flow, premixed combustion, 2-D sudden expansion channel