A missile technique for the study of detonation waves.

Problems and effects of stabilizing combustion and detonation against hypersonic flow were investigated by observation of a 20 millimeter spherical missile in a stoichiometric mixture of hydrogen and air at rest. Combustion produced detectable effects on the shape and position of the shock wave at Mach numbers between 4 and 6.5, and above pressures of one-tenth atmosphere. Chemical equilibrium probably was not reached in the time the gas spent near the front of the sphere. One of the iactors in the delayed equilibrium was delayed ignition behind the shock wave, which was observed to be between about one and ten microseconds. Ignition delay is explained in terms of chemical kinetic theory and compared with results of experiments in shock tubes. Strong combustion- driven oscillations originated in front of the sphere, with frequencies up to about one-tenth megacycle per second. These were observed when the Mach number was less than 6 at a pressure of one-half atmosphere, and less than 5 at one- quarter atmosphere. A large reduction of the drag coefficient of the missile was noted in one case of intermittent combustion. (auth)