Flame-flame interaction analysis of turbulent premixed flames with varying turbulence length scales*

Direct Numerical Simulation (DNS) of premixed hydrocarbon flames is performed using the DNS code Senga2 to investigate the role of varying integral length scale l₀ as well as the turbulence intensity u`. The frequency of flame-flame interactions is analysed for the different cases and the corresponding flame-flame interaction topology is evaluated using the Morse theory of critical points. A matrix of test cases is studied by either systematically varying l<sub>0</sub> at constant u` or by systematically varying u` at constant l<sub>0</sub>. The flame-flame interactions are known to increase with increasing u`, but the same was also found to be true for deceasing l₀. In fact, a striking similarity in the results was observed between the cases with increasing u` and decreasing l₀. The reasons for these observed results are discussed and the mean curvature of the flame is found to play an especially important role. These findings serve to further our understanding of turbulent combustion and the role that the turbulence length scales play in flame propagation.