Lumley

John L. Lumley, the Willis H. Carrier Professor Emeritus of Mechanical and Aerospace Engineering, who made seminal contributions to engineering in the study of turbulent fluid flow, died May 30 of brain cancer in Ithaca. He was 84.

Complex and chaotic, ubiquitous in nature and engineering devices, turbulence is found in cumulus clouds, smoke stacks and jet exhausts.

“It is difficult to think of any facet of turbulence, be it formal mathematical theory, fundamental physics, or engineering and environmental applications, to which John Lumley did not make important contributions,” said Zellman Warhaft, professor of mechanical and aerospace engineering. “More than any other person, he defined the field of turbulence during the second half of the 20th century.”

In the late 1960s Lumley proposed a mechanism that explained drag reduction in terms of the relaxation time of polymers in turbulence – that is the time it takes polymers to uncoil. His explanation still is considered to be the most plausible, despite many other competing theories proposed over the years.

Lumley made important contributions regarding buoyant plumes and smokestacks, turbulent dispersion of pollution in the atmosphere, the propagation of waves in the atmosphere and oceans, turbulence in the presence of atmospheric inversions, the flow of air over objects, the diffusion of salt in water known as “salt-fingering,” and the effects of electromagnetic fields on turbulence.

Lumley’s theoretical contributions that are key to our modern knowledge of turbulence include statistical processes, the identification of structures in turbulence, the cascade dynamics of turbulence, and modeling of generic fluid flows, such as jets and wakes and turbulent flows near walls. In particular, he pioneered the use of “proper orthogonal decomposition” in turbulent flows. Although turbulent flows appear to be random, they also have structures, such as in the wake of an aircraft.

His 1972 book, “A First Course in Turbulence with Henk Tennekes,” was the first book to place dimensional analysis and scaling arguments as central to the subject. In 1964, with Hans Panofsky, he wrote the important “The Structure of Atmospheric Turbulence.” His other books include “Stochastic Tools in Turbulence” (1970), “Turbulence, Coherent Structures, Dynamical Systems, and Symmetry” (1996, with Phil Holmes and Gal Berkooz) and “Engines: An Introduction” (1999). One of his passions was rebuilding old cars, and in 2005 he wrote “Still Life With Cars: An Automotive Memoir.”

In 1990, Lumley received the Fluid Dynamics Prize of the American Physical Society. Other awards include the Fluid and Plasma Dynamics Award of the American Institute of Aeronautics and Astronautics in 1982 and the Timoshenko Medal in 1993. Lumley was a fellow in the American Institute of Aeronautics and Astronautics, the American Academy of Arts and Sciences, and a member of the National Academy of Engineering.

John Leask Lumley was born Nov. 4, 1930, in Detroit. He received his M.S.E. (1954) and doctoral (1957) degrees from Johns Hopkins University. He began his career at the Pennsylvania State University, where he became Evan Pugh Professor of Aerospace Engineering. In 1977 Lumley joined Cornell University as the Willis H. Carrier Professor of Mechanical and Aerospace Engineering. He retired in 2000.

He was predeceased by his wife, Jane Lumley (nee French). He is survived by his children, Katherine Leask Lumley-Sapanski, Jennifer French Lumley and John Christopher Lumley, and five grandchildren.