viii CONTENTS 



4.4 The Shock Wave for CyUndrical Symmetry 126 



4.5 Penney's Theory Based on the Riemann Equations 130 



4.6 The Propagation Theory of Kirkwood and Brinkley 133 



4.7 Comparison of Shock Wave Theories 139 



4.8 Dissipation and Energy of Shock Waves 142 



5. Measurement of Underwater Explosion Pressures 



5.1 Crusher Gauges 147 



5.2 The HilUar Piston Gauge 152 



5.3 Diaphragm Gauges 157 



5.4 Piezoelectric Gauges 159 



5.5 Response Characteristics of Gauges 164 



5.6 Piezoelectric Gauge Design and Performance 169 



5.7 Piezoelectric Gauge Calibration 177 



5.8 Transmission of Piezoelectric Gauge Signals 183 



5.9 Electrical Recording of Underwater Explosion Pres- 



sures 198 



5.10 Experimental Arrangements for Pressure Measure- 

 ments 206 



6. Photography of Underwater Explosions 



6.1 Surface Phenomena 210 



6.2 Optical Considerations in Underwater Photography 211 



6.3 Pressure Measurements by Optical Methods 218 



6.4 Direct Photography 224 



7. Shock Wave Measurements 



7.1 The Form of the Shock Wave 228 



7.2 Experimental Shock Wave Parameters 229 



7.3 Validity of the Principle of Similarity for Shock Waves 235 



7.4 Similarity Curves for Various Explosives 240 



7.5 Comparison of Shock Waves for Different Explosives 244 



7.6 Effects of Charge Shape and Orientation 248 



7.7 Shock Waves from Multiple Charges 255 



7.8 Reflection of Shock Waves at Boundary Surfaces 261 



7.9 The Shock Wave at Large Distances 264 



8. Motion of the Gas Sphere 



8.1 General Features of the Motion 270 



8.2 Noncompressive Radial Motion Neglecting Gravity 272 



8.3 Comparison of Radius and Period Measurements with 



Simple Theory 276 



