An experimental study on head-on collision of detonation with shock

An experimental study on head-on collision of adetonation wave with shock wave in a straight tube was carried out. Highspeed streak schlieren photography was used to illustrate the interactingflow field, and smoke foils were adopted to record the detonation cellularstructure around collision. Based on the theories of shock wave andclassical CJ detonation, the theoectical analyses were also performed toacquire its steady solution and the essential characteristics. Theexperimental showed that the steady wave system after collision consists ofa shock wave and a detonation wave followed by a rarefaction wave fan, whichis consistent with the CJ solution of 1-D theoretical analysis. The initialwave pressure has no effect on the wave system and the initial temperatureremarkably affects the wave and flow velocities. Meanwhile, the strength ofthe incident shock wave has the most important influence on the transmittedflow system, that is, strong shock induces the whole flow field towards theshock direction. Rarefaction is inevitable in the system unless the incidentshock tends to Mach one, and stronger shock usually results in more expandedrarefaction zone. Experimental study also revealed that the detonation waveexperiences a transit process after collision, where it first slows down andthen bursts into an overdrived detonation which then undergoes a subsequentequilibrium process towards CJ state. This transit process usually developsunsteadily in the highly irregular mixture. Seroius decoupling of shock andflame may occur in some region, and the decoupled flame could rapidlydevelop new cellular detonation even before it overtakes the decoupledprecursor shock. Very fine cellular traces printed by this kind ofdetonation were observed in our smoke foil results.