Dr. Cohen, Mechanical Engineering

Dr. Ira M. Cohen, professor emeritus of mechanical engineering and applied mechanics in the School of Engineering and Applied Science, died December 8, 2007, at the age of 70. Dr. Cohen earned his BS from Brooklyn Polytechnic University in 1958 and his PhD from Princeton University in 1963, both in aeronautical engineering. He taught at Brown University for three years prior to joining the University of Pennsylvania faculty as assistant professor in 1966. He served as chair of the department of mechanical engineering and applied mechanics from 1992 to 1997.

Dr. Cohen was a world-renowned scholar in the areas of continuum plasmas, electrostatic probe theories and plasma diagnostics, dynamics and heat transfer of lightly ionized gases, low current arc plasmas, laminar shear layer theory, and matched asymptotics in fluid mechanics. Most of his contributions appear in the Physics of Fluids journal of the American Physical Society. His seminal paper, Asymptotic theory of spherical electrostatic probes in a slightly ionized, collision dominated gas (Phys. Fluids: 1492-1499, 1963), is to-date the most highly cited paper in the theory of electrostatic probes and plasma diagnostics. During his doctoral work and for a few years beyond that, Dr. Cohen collaborated with the world-renowned mathematician/physicist, the late Dr. Martin Kruskal (recipient of National Medal of Science, 1993) on the development of a monograph called “Asymptotology.” Dr. Kruskal also collaborated with Dr. Cohen on plasma physics. This was the basis for Dr. Cohen’s strong foundation in Plasma Fluid Dynamics.

Among his recent contributions is the highly acclaimed, graduate course-level textbook, Fluid Mechanics,with the late Professor P. K. Kundu, published by Elsevier Academic Press, which has just been released in its 4th edition.

“Dr. Cohen’s dedication to academics was unrivalled. In addition, his passion for physical fitness was legendary. Neither rain nor sleet nor snow would deter him from his daily bicycle commute, which began at 5 a.m., from his home in Narberth to Penn. His colleagues grew accustomed to seeing him drag his forty-year old bicycle with its original three-speed gear shift, up to his office. His other great passion was the game of squash, which he played with extraordinary skill five days a week at the Ringe Squash Courts at Penn. He was a fierce but fair competitor, whose joy at playing the game touched the lives of the hundreds of recreational squash players with whom he played over the years. A small plaque in Dr. Cohen’s honor was recently installed at the Ringe Squash Courts,” said his colleagues.

Dr. Cohen is survived by his wife, Linda; his two daughters, Susan Cohen Bolstad and Nancy Cohen Cavanaugh; and three grandchildren, Melissa, Daniel, and Andrew.