STUART B. SAVAGE (1932-2024)

BY ANTHONY ROSATO
SUBMITTED BY THE NAE HOME SECRETARY

STUART BLACKTON SAVAGE, a distinguished and preeminent scholar in the field of engineering mechanics and granular materials, passed away peacefully, surrounded by family, on Nov. 26th, 2024, at the age of 92 in Montreal. He was born in Far Rockaway, New York, and enrolled in the mechanical engineering program at McGill University in 1950. After one year of study, he enlisted in the U.S. Air Force and spent the next four years working in the Aerodynamics Laboratory at Wright Field in Dayton, Ohio, on problems related to the performance of fighter aircraft, including the F-100, F-102, XF-103, F-104, and F-105. Upon discharge, he returned to McGill and earned a degree with honors in mechanical engineering in 1960. That summer, under the supervision of Barry Newman, he conducted research on laminar separation bubbles. He was then awarded a Guggenheim Fellowship for graduate studies in jet propulsion and space flight sciences at the California Institute of Technology, where he earned a Master of Science in 1961, followed by an aeronautical engineer’s degree in 1962. His advisor was Lester Lees (NAE 1971), a leading authority in hypersonic aerodynamics.

Stuart accepted a position as principal aerodynamics engineer in the Applied Research and Development Center of Republic Aviation in Farmingdale, New York. There, he conducted both theoretical and experimental work related to the Aerospace plane — a precursor to the Space Shuttle — designed to reach orbit and speeds of up to Mach 20. His supervisor and mentor at Republic, Robert Senator, passed away in July 2024, just four months before Stuart.

Stuart returned to McGill in 1964 as a lecturer while simultaneously pursuing a doctorate in applied mechanics. In the summer of 1966, he worked at TRW Inc. evaluating the performance of an electron seeding device. He returned to McGill and completed his Ph.D. in 1967 with a dissertation titled “Some Consideration of Flow of Cohesionless Granular Soils.” While at McGill, he met his future wife, Barbara (née Gatehouse), whom he married in 1968. He was appointed assistant professor in civil engineering and applied mechanics in 1967 and retired as professor emeritus in 1997.

Over the course of his long and prolific research career, Stuart made numerous seminal contributions to the mechanics of granular materials, developing both continuum and statistical theories as well as computer-simulated models informed by laboratory and field experiments. The importance of his work is far-reaching, as nearly every product or commodity used globally today is composed of or derived from granular materials through mining, agriculture, or chemical processing — all of which together contribute trillions of dollars to the global economy. Applications of Stuart’s theories span materials handling and processing, fluidized beds, and the manufacture of pharmaceuticals and ceramics. In addition, his theoretical insights have been highly relevant to geophysical phenomena such as debris flows, avalanches, and wind-driven Arctic pack ice.

No tribute would be complete without mention of Stuart’s pioneering collaboration with James Jenkins of Cornell University. Together, they developed the first kinetic theory model of energetic (rapid) granular flows. This foundational work, extended over decades, has greatly enhanced our current understanding of the intricate nature of interacting particle-based systems. Stuart’s lifelong work in formulating constitutive laws for these intricate materials has enabled engineers and scientists to approach granular problems with a degree of confidence once reserved only for traditional fluids and solids.

Stuart delivered numerous keynote and opening lectures at major international conferences and was highly active in professional societies and the organization of influential conferences and symposia worldwide. He held visiting professorships at the Swiss Federal Institute of Technology in Zurich, École Supérieure de Physique et de Chimie Industrielle in Paris, the University of Rennes, and the Technological Institute at Darmstadt. He also served as an academic visitor at Imperial College London and was a frequent senior visitor at the Department of Applied Mathematics and Theoretical Physics at Cambridge University. In recognition of his contributions, he was elected a fellow of the Royal Society of Canada; a life member of Clare Hall, Cambridge University; and a member of the National Academy of Engineering. He was honored by the Institute for Scientific Information as one of the 100 most-cited researchers in engineering of the 20th century. In 2024, Mechanics Research Communications (under the auspices of Elsevier) established an international award in his name to honor a senior scientist who has made paradigm-shifting contributions to the mechanics and physics of granular materials and discrete particle systems.

Stuart mentored, supported, and advised many graduate students, all of whom went on to have successful careers in academia and industry. He was genuinely kind and considerate to everyone and often extended himself to help others, especially young researchers just starting their careers. A connoisseur of fine cuisine, he was known for discovering superb restaurants where he would dine with colleagues and friends during conferences and meetings. He had a wonderful sense of humor, and it was always a delight to be in his presence. Stuart was a true gentleman and a scholar who, despite his many achievements and accolades, remained humble and understanding throughout his life.

He is survived by his wife, Barbara; his sister, Anne Elizabeth; his daughter, Ainsley (Trevor Gillingwater); his son, Todd (Maria Nikoloudakis); and his grandchildren, Jasmine, Tyler, Ava Savage, and Virgil Gillingwater.