Three-Dimensional Instabilities Downstream of a Detonation Wave

It is known that a detonation wave is inherently unstable.  The instability has been observed previously in two-dimensional computational simulations to form diamond-shaped cellular patterns downstream.  A recent three-dimensional Euler solution by Dou et al. (2008) showed that the cellular structure is absent, raising the possibility that the cellular pattern is a “footprint” or an integrated impression of the three-dimensional field.  The present study examines the data from a direct numerical simulation which captures all physical length and time scales with no simplifying assumptions.  This work reveals the presence of three-dimensional instabilities throughout the entire downstream domain.  The presence of random disturbances when integrated appears to form cellular structures.  Further work is needed to determine the nature of these disturbances and how they evolve.