That’s Shocking! The Physics of Nonlinear Sound Waves With Examples

Dr. Kent Gee
Department of Physics and Astronomy
Brigham Young University


Like other areas of physics, fascinating phenomena occur in acoustics when amplitudes become large enough that the simplifying assumptions we’re fond of making begin to break down.  The speed of sound is no longer the constant that we’re taught in introductory physics – different parts of the wave travel at different speeds, causing the wave’s shape to distort and shocks to form. What kind of amplitudes are required for these shocks to form?  Where do they occur?  What damage can they cause?  How can they be mitigated or harnessed for our benefit?   In this presentation, I’ll describe nonlinear sound waves and shock formation and discuss examples from my research, including military jet aircraft, rockets, Gatling guns, and explosions.  I’ll also talk about sonic booms and their mitigation, and how nonlinear sound waves can be used to break up kidney stones and produce highly directional audio.