PH3452 Underwater Acoustics

This course is a continuation of PH3451. Lumped acoustic elements and the resonant bubble; introduction to simple transducers; normal modes in rectangular and cylindrical enclosures; steady-state response of acoustic waveguides of constant cross section, propagating evanescent modes, and group and phase speeds; transmission of sound in the ocean, the Eikonal Equation and necessary space conditions for ray theory, and refraction and ray diagrams; sound propagation in the mixed layer, the convergence zone, and the deep sound channel; passive sonar equation, ambient noise and doppler effect and bandwidth considerations; active sonar equations, target strength and reverberation. Laboratory experiments include Helmholtz resonators, normal modes in rectangular, cylindrical, and spherical enclosures, water-filled waveguide, noise analysis, impedance of a loudspeaker.

Prerequisite

PH3451

Lecture Hours

Lab Hours

Course Learning Outcomes

Upon successful completion of this course, a student will be able to:

Plot and analyze ray paths in isogradient layers of water;
Calculate the reflection and transmission of plane sound waves incident on the planar interface between two different fluids;
Estimate transmission loss for simple models such as mixed layer, convergence zone, bottom bounce, reliable acoustic path, and SOFAR channel;
Set up underwater acoustics experiments, acquire reliable data, and use the acoustic measurements to characterize the system;
Use sonobuoy data to calculate the speed, depth, and distance of closest approach of an uncooperative target;
Determine source levels and beam patterns for sources and arrays of scalar and vector sensors;
Evaluate detected noise levels and reverberation levels for various environmental conditions;
Calculate the target strength of basic scatterers, including gas bubbles;
For given sonar and target characteristics, estimate the range of detection.