Brad Sturtevant’s contributions to research on shock waves and lithotripsy

Bradford Sturtevant (1933–2000) spent his entire academic career in the Graduate Aeronautical Labs at Caltech (GALCIT). He was a distinguished and internationally respected member of the fluid mechanics community, known particularly for his research on shock waves. Although a member of the Acoustical Society since 1974, he rarely if ever published in JASA. Nevertheless, his contributions to acoustics, mainly in what we think of as nonlinear acoustics although he probably saw them simply as part of fluid mechanics, are significant. Examples are: shock focusing, nonlinear resonance in closed‐ and open‐end tubes, sonic booms, and propagation of weak shocks through a random medium. In the late 1980s he became interested in lithotripsy. When Andrew Evan (Indiana University School of Medicine) organized a multidisciplinary consortium to solve many of the mysteries of lithotripsy, it is not surprising that Brad was picked for his expertise on shock waves and his interest in shock waves in the body. The research effort that ensued, now in its eighth year, owes much to the work of Brad and his students and to his counsel. Brad was especially concerned about the mechanism(s) by which stone breakup occurs.