Detonations with lateral strain rate: piece-wise laminar detonations

Combustion and Flame 215 (2020) 437–457

We now show that unstable detonations with long reaction zones, such as H2/O2/Ar, can be very well predicted by the ZND model, which neglects the cellular structure.

This may come as a surprise, since the cellular structure takes very high amplitude perturbations, and the transverse waves are among the strongest of all detonations, i.e., they are reactive.

The good agreement with ZND predictions is likely because of their very long reaction zones, as compared to the induction zones, as shown by their ZND profiles:

The cellular structure locally changes the induction zone length along the front, as shown in the photos (Fig. 12) above, but leaves the much longer reaction zone non-affected.  Since the global divergence competes with the net rate of energy release in dictating the eigenvalue solution, and the latter is weakly affected by the cellular structure, then the ZND works well.