Hugh G. Flynn, an internationally recognized expert on ultrasonic waves' violent effects on air bubbles in liquids -- a topic with applications in energy, medicine, and manufacturing -- died at the Kirkhaven Presbyterian Home in Rochester on May 23. Flynn, professor emeritus of electrical engineering at the University of Rochester, was 84.
Flynn joined the Rochester faculty in 1960, becoming professor emeritus of electrical engineering in 1978. During his tenure, Flynn served as acting chair of the electrical engineering department from 1969 to 1971 and as associate dean of the University's College of Engineering and Applied Science from 1968 to 1972. He also played a key role in the founding of the University's computer science department, chairing two committees in the early 1970s that recommended its establishment and then named the department's first chair.
Flynn's research on acoustic cavitation -- the study of how air bubbles in liquids react when exposed to intense sound waves -- made him an internationally known figure in that field. When struck by such sound waves, bubbles undergo a series of violent compressions and expansions. The force exerted by such bubbles can easily damage nearby surfaces; among other effects, cavitation is known to cause pitting on ships' propellers.
In 1964, Flynn authored a seminal textbook chapter on the physics of acoustic cavitation in liquids that has since been cited in hundreds of technical publications. He also wrote a 1972 Environmental Protection Agency report to Congress and the President on the effects of sonic booms on structures.
More recently, Flynn's research interests focused on the role of cavitation in ultrasound. Since 1982, he had written several papers on the role acoustic cavitation plays in lithotripsy, a medical procedure that uses rapid ultrasonic pulses to destroy kidney stones. At the time of his death, Flynn was working on a line of research stemming from his pioneering 1982 patent on the use of cavitation to attain nuclear fusion.
Born on December 8, 1912 in Lancaster, Ohio, Flynn spent the 1930s working as a reporter for the Ohio State Journal in Columbus. He then moved on to work as a physicist in the Navy's Bureau of Ordnance and served as an officer in the U.S. Navy during World War II. In 1946, Flynn earned a B.A. in physics from Ohio State University and an M.S. in physics from Rensselaer Polytechnic Institute. He worked for the National Academy of Sciences' Committee on Undersea Warfare for a time before returning to academia to earn an M.A. in applied physics in 1950 and a Ph.D. in 1956, both from Harvard University. Flynn served as deputy director of Harvard's Acoustics Research Laboratory before coming to Rochester in 1960.
Predeceased by his wife, Prudence, Flynn is survived by two daughters, Katherine M.G. Flynn of Massachusetts and Mary S.W. Flynn of Virginia, and a son, Hugh N. Flynn of Massachusetts. The family asks that contributions in Flynn's memory be made to the Kirkhaven Presbyterian Home.