Acoustical Society of America
R. Bruce Lindsay Award - 1991

Yves H. Berthelot

Yves Henri Berthelot was born on 18 April 1957 in Neuilly-sur-Seine, a suburb of Paris, and received his early education in Paris. In September 1975 he entered the recently established Université de Technologie de Compiègne (about 40 miles north of Paris) and began to study engineering. Acoustics was part of Compiègne's curriculum in mechanical engineering, and this was the catalyst that eventually led to Yves' career as an acoustician. He had been playing the violin since the age of six, and all other things being equal, why not pursue a curriculum where one can learn about the science that underlies music? Acoustics was not immediately perceived as a viable career choice, but the possibility emerged when the Institute of Sound and Vibration Research (ISVR) at the University of Southampton, in England, negotiated an agreement with Compiègne who received fellowships from the French Department of Foreign Affairs for the ISVR program.

The 16 months in Southampton involved intensive instruction in the fundamentals and applications of acoustics and vibration. Among those whom Yves met during this period was Joseph Cuschieri, who was then doing his doctoral work, and who was eventually to become Yves' co-winner of the 1991 Lindsay Award. Yves did his M.Sc. thesis work at ISVR with Christopher L. Morfey, an eminent researcher on aerodynamic sound, impact, and nonlinear acoustics. Yves' topic involved the processing of aircraft noise signatures taken at ground level from planes in flight and checking out Morfey's theory concerning the influence of nonlinear propagation effects on the statistical features of such signatures; the data analysis verified the theory. Chris encouraged Yves to continue on past the M.Sc. with doctoral studies and suggested that Yves contact his American colleague, David Blackstock, in Austin. In the due course of time, Yves was admitted to doctoral work in the Mechanical Engineering Department at the University of Texas and given a Research Assistantship in the Applied Research Laboratories (ARL:UT). He arrived in Austin in January 1982.

Yves's arrival coincided with ARL's receipt of a contract from the Office of Naval Research to resume some laser-generated sound research that had been carried out at ARL during the mid-1970s; the principal distinction from the earlier experiments was that the laser beam would be moved over the water surface, rather than kept pointed at a single spot. Yves was given a pile of papers on the subject, including an extensive collection by leading Soviet researchers such as Lyamshev, Bunkin, Naugolnykh, and Sedov, which would have been heavy reading even for experts in the field of opto-acoustics. The responsibility for assembling the apparatus for the experiment, and for seeing that the project was carried out, fell for the most part on Yves. It was an awesome assignment for a student whose background was in mechanical engineering, who knew virtually nothing about lasers and optics, and whose research experience was very limited, but Yves persisted and made an extreme effort to do well in the task. That he succeeded and did so far beyond anyone's initial expectations is now somewhat of a legend at the Applied Research Laboratories. He did of course get some help along the way. Ilene Busch-Vishniac, who would later win the 1987 Lindsay Award, joined the faculty of the Mechanical Engineering Department in the Fall of 1982 and, at David Blackstock's suggestion, undertook the task of guiding Yves' thesis. It was a fruitful association of two extremely talented young researchers, and each learned much from the other. Ilene once remarked that having Yves as her first doctoral student may have spoiled her somewhat. She on the other hand set the high standard for quality of research and for productivity that Yves has endeavored to maintain ever since. During his graduate student days at Texas, Yves continued to progress also with his academic studies and interacted with other acoustics researchers, including the 1989 Lindsay Award winner, Mark Hamilton, with whom he shared an office at ARL and later shared an apartment.

Yves attended his first meeting of the Acoustical Society of America and presented his first paper in November 1983. His first manuscript, coauthored with Busch-Vishniac, was submitted to the Journal in mid-1984. This and three other papers on laser-induced sound, dealing with both theory and experiment and resulting from his work at Texas, were eventually published in the Journal.

In the Fall of 1985, Yves joined the faculty at the Georgia Institute of Technology, which was then beginning to emerge as a major research center in acoustics. Jacek Jarzynski, who was also interested in laser applications, came the same year. Peter Rogers, who had sponsored the ARL:UT laser-induced sound work at Texas during his stint at the Office of Naval Research, had come the preceding year. Allan Pierce was at that time doing theoretical studies on the subject; and Jerry Ginsberg was doing research in nonlinear acoustics. There were further papers on the use of optical fibers to enhance laser generation of sound (coauthored with Jarzynski) and on the relevance of nonlinear effects in laser-induced sound (coauthored with Pierce). Another, with graduate student Joseph Vignola and with Jarzynski, concerned the use of the Doppler shift to measure acoustic amplitudes. Other research was carried out on sound propagation over irregular terrain. There were hitherto unanswered questions and also some controversy concerning sound near the top, and near the border between illumination and shadow on the far side, of curved surfaces with finite impedance. Berthelot, in collaboration with several colleagues, carried out some laboratory experiments using spark sources and a model hill, with various coverings, and then compared the results with a theory proposed originally by Pierce. This work led to the first doctoral thesis (James Kearns, currently with ARL in Austin) supervised by Berthelot. A paper on this subject which Yves presented at an American Institute of Aeronautics and Astronautics (AIAA) aeroacoustics conference in 1987 subsequently was recognized by the AIAA as being one of the two outstanding papers at that meeting.

The Acoustical Society of America remains Yves' primary professional affiliation. He is currently serving on the technical committees for both Physical Acoustics and Underwater Acoustics, as well as on the Committee on Education in Acoustics. A mainstay of the Georgia Chapter, he served as President in 1986–1987, and as Secretary from 1988 to the present.

In 1988, Yves received a Presidential Young Investigator Award from the National Science Foundation for his work on acoustic transduction with laser beams. This work was also highlighted as one of the newsworthy achievements of 1988, resulting in an article (coauthored with Pierce) that appeared in the January 1989 issue of Physics Today. In 1989 he received the Sigma-Xi Junior Faculty Award for being the outstanding young faculty member at Georgia Tech. Yves is also on the Editorial Board of Applied Acoustics and was coauthor of a chapter on "Acoustics" in Eshbach's Handbook of Engineering Fundamentals. At latest count he has coauthored over 20 papers and reports, and has given 7 invited presentations and 16 contributed presentations at various national and international meetings.

Playing the violin is still Yves' principal avocation. While at ISVR, he played with the Southampton University Symphony Orchestra; at Texas, he played regularly with a small chamber group (of which fellow acoustician Jim Hadden was also a member); currently he plays with the Atlanta-Emory Symphony Orchestra. A more recent extracurricular interest is flying, and he now has a private pilot's license. One of Yves' cherished honors is the receipt of the "absent-minded professor" trophy at the 1990 ME Department Awards Banquet. Yves went to the podium to receive the award, said the customary few words of thanks for the honor, and then returned to his seat, forgetting to take the trophy back with him, causing howls of laughter from the audience. The lapses of memory, however, are only on minor and mundane matters. A fluent speaker in three languages (the third is Italian), he is a charming conversationalist, who occasionally illustrates his ideas with stories about the lives of the great composers and with quotations from Voltaire. Yves is somewhat of a Renaissance man himself, and he is definitely appropriately placed in this part of the 20th (as well as the 21st) century to help lead the venerable, but very vigorous, science of acoustics to higher levels of technological innovation and fundamental understanding.

ALLAN D. PIERCE