PH3451 Fundamental Acoustics

Development of, and solutions to, the acoustic wave equation in fluids; propagation of plane, spherical and cylindrical waves in fluids; sound pressure level, intensity, and specific acoustic impedance; normal and oblique incidence reflection and transmission from plane boundaries; transmission through a layer; image theory and surface interference; sound absorption and dispersion for classical and relaxing fluids; acoustic behavior of sources and arrays, acoustical reciprocity, continuous line source, plane circular piston, radiation impedance, and the steered line array; transducer properties, sensitivities, and calibration. Laboratory experiments include longitudinal waves in an air-filled tube, surface interference, properties of underwater transducers, three-element array, speed of sound in water, and absorption in gases.

Prerequisite

PH3119, PH3991

Lecture Hours

4

Lab Hours

2

Course Learning Outcomes

Upon successful completion of this course, a student will:

  • Understand sound pressure oscillations in a fluid medium and derive the linear wave equation from first principles
  • Express simple solutions to the wave equation such as plane-, spherical-, and cylindrical-waves using exponential notation
  • Characterize the energy carried by sound waves and the relationship between intensity and geometrical spreading of the wavefront
  • Relate frequency, wavelength, and wavenumber via the speed of sound
  • Quantify sound levels in units of decibels
  • Use the principle of superposition and Fourier Synthesis to describe broadband sound
  • Calculate the reflection, transmission, and refraction of plane waves at the interface between two media
  • Understand the mechanism by which an acoustic source (e.g., a baffled piston) radiates sound energy into the medium
  • Understand how and why acoustic waves attenuate as they propagate
  • Identify acoustic standing wave patterns, resonant frequencies, and normal modes in enclosures
  • Use microphones to measure sound pressure for experiments and condition the signal with filters and amplifiers to optimize signal-to-noise ratio
  • Perform measurements of sound radiation patterns in an anechoic chamber and operate a lock-in amplifier.