The structure of marginal detonation waves

A new type of marginal detonation wave was observed in a 3 × 14in. tube using a 2H2 + O2 + 3 Ar mixture at 58 torr initial pressure. Its structural details were determined using a combination of laser streak schlieren and smoked foil records. It was found that under these conditions the detonation contained a strong transverse wave system that became a transverse detonation near the end of each cell. It was also found that in this marginal situation the cell size of the detonation increased to 2.29 times its ordinary value. A comparison is made between this structure and both the structure of a single spin detonation in a round tube and an ordinary well-established propagating detonation in a large tube.