Martin Lessen, a professor emeritus and former chair of the Department of Mechanical Engineering at the University of Rochester who played an important role in forming the department, died Sunday, Jan. 24, in Rochester. He was 78.
Lessen joined the University faculty in 1960 as the chair of the Department of Mechanical and Aerospace Sciences at a critical time, just as the College of Engineering had been created and research efforts in engineering were being beefed up. Lessen served as chair from 1960 to 1970 and hired several faculty members, bringing together experts from such areas as physics and mathematics to create a non-traditional engineering department with wide-ranging interests. Under his leadership the department became known worldwide for its studies of plasma physics; the research effort eventually led to the creation of the University's Laboratory for Laser Energetics, a world-class center for the study of fusion and lasers.
Lessen was regarded by his peers as an authority in the fields of fluid dynamics, plasma dynamics, energy conversion, and thermoelasticity. He performed some of the early research on hydrodynamic stability theory, and he applied his findings to the study of mixing in fluids.
"Martin was a very creative person who combined fundamental theoretical understanding with an ability to visualize and create new devices," says Al Clark, a professor of mechanical engineering and one of several current faculty members hired by Lessen. "He had an enormous zest for living and was an extremely important person in the history of the department."
Lessen was also an avid musician who, while a graduate student at the Massachusetts Institute of Technology, was a soloist on high trumpet with the Boston Pops Orchestra. He also had an extensive collection of historic trumpets and related instruments, and he even created a new kind of trumpet.
A native of New York City, Lessen earned his bachelor's degree in mechanical engineering at City College of New York, his master's at New York University, and his doctorate from MIT. Before coming to the University, Lessen was on the faculties of Pennsylvania State University and the University of Pennsylvania; soon after joining the University he was named Yates Memorial Professor of Engineering. Lessen was known for his efforts to modernize and upgrade engineering education around the nation, and in 1964 played a leading role in founding the Energetics Division of the American Society of Mechanical Engineers.
Lessen was a fellow of the American Society of Mechanical Engineers, the American Physical Society, and the American Association for the Advancement of Science. During his career he worked with three dozen doctoral students, published more than 150 papers, and had several patents. He served as a National Academy of Science Exchange Lecturer to the Soviet Academy of Science in 1967. He was also co-founder of Rochester Applied Sciences Associates Inc., a research and development firm that did research in aeronautics, acoustics, structural dynamics, and mechanics.
Lessen is survived by his wife, Elizabeth, of Pittsford, N.Y.; daughters and sons-in-law Margot Lessen Brody and Edward Brody of Wayland, Mass.; Deborah Lessen Calomino and Joseph Calomino of New York City; a son, David Lessen, of New York City; grandchildren Melissa, Joel, and Diana Brody, and Noah Martin Calomino; sisters and brothers-in-law Anna and Meyer Needleman, and Sherry and Len Rand; and several cousins, nieces and nephews.
A memorial service will be held at a time and place to be announced.