560 



INDEX 



Cable hydrophones, 74-75 



Calibration techniques for sound meas- 

 urements, 492 

 reverberation intensities, 277 

 target strengths, 368-369 

 transmission loss, 76-78 



Canadian National Research Council, 

 attenuation measurements, 105 



Cathode-ray oscilloscope tor acoustic 

 wake measurements, 488-490 



Cavitation in bubble formation, 191, 

 449-450 



CHARLIE bathythermograms, 93 



Chemical recorder traces in acoustic 

 wake measurements, 484 



"Chirp" signal in echo-ranging gear, 23 



CN-8 crystal hydrophone, 74 



Coherence in sound reverberation, 335 

 ampUtude, 327-329 

 intensity, 339 

 transmission, 71 



Compression viscosity in attenuation of 

 sound, 28 



Configurational averages for acoustic 

 theory of bubbles, 468 



Conservation of energy law for second- 

 ary sound pressure waves, 186- 

 188 



Continuity law in sound wave propaga- 

 tion, 8-10 



Continuous-iiow bubble screens for 

 acoustic measurements, 477 



Convex surface, target strength meas- 

 urements, 359, 434 



"Cross-section" of bubble, 461 



CW pings, frequency analysis of rever- 

 beration, 329-331 



Cylinder surfaces, target strength meas- 

 urements, 360, 435 



Damped vibration, 28 

 Damping constant, 467, 535-536 

 Decay rate in sound transmission 



acoustic wakes, 520-521, 539-540 



bottom reverberation, 322 



echo intensity, 526 



shock waves, 184-186 



surface reverberation, 337 

 Deep-water reverberation of sound 



average reverberation levels, 304-306 



deep scattering layers, 282-284 



definition, 86-89 



echo ranging, 527-530 



frequency effects, 284-288 



multiple scattering effects, 303-304 



oceanographic conditions, 289 



ping length, 302 



range dependence, 289-302 



scattering coefficient, 306-307 



transducer directed downward, 281- 

 288 



transducer horizontal, 288-299 



volume reverberation, 281-282, 284- 

 288, 335-337 

 Deep-water transmission of sound 



see Transmission of sound, deep- 

 water 

 Density-pressure properties of a dis- 

 turbed fluid, 11-12 

 Depth effects in sound transmission 



bathythermograms, 92-95 



bottom reverberation level, 338 



corrections, 49-51 



ray diagrams, 89-90 



temperature gradients, vertical, 90- 

 92 



thermocline transmission, 115-117 



volume reverberation, 282-284 

 Destroyer wakes, air bubble hypothesis, 



534 

 Detonation process in underwater ex- 

 plosions, 173-175 

 Diffraction of sound waves 



hypothesis, 201 



nonspecular reflection, 361 



pressure-time records, 204-206 



ray theory, 41 



shadow zones, 65-66, 200-201 



wave equation, 66-68 

 Direction of sound propagation 



definition, 5-6 



directivity index, 72 



double source, 24—26 



pattern functions, 26-27 



point source, 24 



transducer patterns, 429^30, 522 

 Doppler effect 



reverberation, 329-331 



wake measurements, 484 

 Double layer effect in sound propaga- 

 tion, 200 

 Double sources of sound, 24-26 

 Drift effect in echo variability, 376 



EBI-1 crystal transducer, 276 

 Echo intensity measurements 



angular variation, 546 



definition of echo level, 434 



long pulses, 515-516 



short pulses, 516-519 



target strength, 347-348, 351, 377 



variabUity, 374-378 

 Echo ranging 



equipment, 85 



frequency, 523 



projectoi-s, 241 



pulse length, 522-523 



shallow-wat«r, 321-323 



submarine wakes, 523-526 



surface vessel wakes, 526-530 



target strengths, 343-344, 376 



temperature gradients, 3-4 



thermochne, 109-110 



transducer directivity, 522 



wake measurements, 484, 490-493 

 Echoes, wake 



beam echoes, 415^17, 435-436 



decay, 539-540 



off-beam echoes, 417-420, 436-437 



propellers, 539 



repeater, target training, 85 



source, 420-^21 



submerged submarines, 437 



surface vessels, 437 



target strengths, 377, 435 



wake theory, 535-537, 543-546 

 Eckart, seff-correlation coefficient for 

 soimd intensity fluctuations, 166 

 Eikonal wave equation in ray acoustics, 



44r45, 64-65 

 Electromagnetic sources for sonic fre- 

 quencies, 72 

 Elongation phenomena of off-beam 



echoes, 418-420 

 Entrained air in acoustic wakes, 455-457 

 Equations for target strengths 



definition, 347 



derivations, 348-350 



reflected pressure, 355 

 Equations of wave propagation, 8-14, 

 43-45 



boundary conditions, 13-14 



continuity, 8-10 



differential equations of rays, 45-46 



differential equations of wave fronts, 

 43-45 



forces in a perfect fluid, 10-11 



initial conditions, 13-14 



motion, 10 



ray paths, 46-47 



state of fluid, 11-12 



wave equation, 12-13 

 Equipment for reverberation measure- 

 ments, 272-277 

 Explosions, underwater, 173-235 



attenuation, 193-197 



bottom reflection, 219 



cavitation, 191 



deep sound channels, 213-216 



diffraction, 200-206 



Fourier analysis, 206-211 



long-range propagation, 211-213, 

 216-219 



normal mode theory, 224-229 



predictions of ray theory, 222-224 



pressure waves, secondarj', 186-190 



reflection coefficients, 220-222 



refraction, 197-200 



shallow-water experiments, 229-235 



shock fronts, 175-177, 182-184 



shock waves, 184-186 



summary, 173-175 



surface reflection, 190-191 



