Initial Wave Phenomena in a Weak Spherical Blast

The initial waves created by the sudden release of a spherical volume of compressed air in a limitless environment of air at constant state are predicted analytically using an iterative method of solution by characteristics for the case of a specific weak blast. Pressure-time records have been obtained within the compressed air and in the immediate environment of the spherical blast during its early stages using a pyramidal shock tube. The experimental results corroborate the existence and position in time and space of the inner and reflected shock waves predicted analytically. The present results for a weak spherical blast are in substantial agreement with the analytical and experimental results obtained previously by other investigators for a considerably more powerful blast. The shock tube, in pyramidal or conical form, appears to offer considerable promise for further research on spherical blast phenomena.