Beyond Chaos: The Continuing Enigma of Turbulence 

The everyday phenomenon of turbulence is one of the grand challenges of classical physics.  This seemingly random, unpredictable motion of fluids is pervasive and completely familiar to us all.  Turbulence governs the speed at which rivers flow and the air drag as you drive your car; it is the bane of air travelers.  Turbulence can kill, by causing arteries and aneurisms to burst. Turbulence makes stars twinkle.  Its random but structured patterns have inspired artists and scientists alike.  And yet, despite a century of scientific investigation, our understanding is primarily based upon a mere handful of early seminal insights.  In this talk, I'll try to explain why this problem is so difficult, much harder than chaos, and what it would mean to solve it.  In particular, I will show that regarding turbulence as a problem in non-equilibrium statistical mechanics yields novel predictions that have been tested in two-dimensional turbulence.  Finally, I'll discuss recent dramatic advances in both experiment and theory that account for the way in which fluids start to become turbulent as their flow velocity is increased, making precise mathematical contact with transitional behavior in a seemingly disconnected problem: predator-prey ecosystems.

Dr. Nigel Goldenfeld holds the Chancellor's Distinguished Professorship in Physics and joined UCSD in Fall 2021 after 36 years at the University of Illinois at Urbana-Champaign (UIUC). Nigel's research spans condensed matter theory, the theory of living systems, hydrodynamics and non-equilibrium statistical physics.

Nigel received his Ph.D in theoretical physics from the University of Cambridge (UK) in 1982, and for the years 1982-1985 was a postdoctoral fellow at the Institute for Theoretical Physics, University of California at Santa Barbara, where his work on the dynamics of snowflake growth helped launch the modern theory of pattern formation in nature. He joined the condensed matter theory group at the Department of Physics, UIUC in 1985, where his work was instrumental to the discovery of d-wave pairing in high temperature superconductors. In 1996, Nigel co-founded NumeriX, a company that develops high-performance software for pricing and risk managing derivative securities. Nigel's interests in biology include microbial ecology, evolution and systems biology. He was a founding member of the Institute for Genomic Biology at UIUC, where he led the Biocomplexity Group and directed the NASA Astrobiology Institute for Universal Biology. During the COVID-19 pandemic, he pivoted from his experience in mathematical modeling of bacteria and viruses to computational epidemiology, advising the Governor of Illinois, and helping devise, set up and run the COVID saliva testing system at UIUC, which provided ~12-hour turnaround of PCR tests to the 50,000 people in the campus community and eventually to over 1700 schools and other institutions in Illinois and beyond. Nigel has served on the editorial boards of several journals, including The Philosophical Transactions of the Royal Society, Physical Biology and the International Journal of Theoretical and Applied Finance. Selected honours include: Alfred P. Sloan Foundation Fellow, University Scholar of the University of Illinois, the Xerox Award for research, the A. Nordsieck award for excellence in graduate teaching and the American Physical Society's Leo P. Kadanoff Prize 2020. Nigel is a Fellow of the American Physical Society, a Fellow of the American Academy of Arts and Sciences, a Fellow of the Royal Society (UK) and a Member of the US National Academy of Sciences.