Description: Geoffrey Vasil will discuss a large frictionless pendulum chain. He will show how to solve numerical simulations of this system for thousands of links efficiently enough to study behavior found in the continuum and thermodynamics limits. Even though the system contains no friction and conserves total energy, it develops behaviors typically seen in dissipative systems, e.g., thermalization, damping, emergent oscillations etc. On the other hand, the system is simple enough to make analytical progress in studying its equilibrium states. The only problem is that the analytical calculation predicts starkly different results from the direct simulations. Vasil has no real idea why, but he speculates about some of the resolutions to these paradoxes. Thinking how a system as simple as this can go off the rails may hint at places to worry about in more complex applications.
Speaker bio: Geoffrey Vasil earned his Ph.D. in geophysical and astrophysical fluid dynamics at the University of Colorado, under the supervision of Nic Brummell. Before that, he studied mixtures of pure and applied mathematics and theoretical physics. His postdoctoral work comprised time in astrophysics at the University of Toronto and University of California, Berkeley. He was a faculty member at the University of Sydney for nine years before recently moving to the University of Edinburgh, where the Queen’s funeral procession passed 20m outside of his kitchen window. He works on topics surrounding physical applied maths, fluid mechanics, solar magnetohydrodynamics, mathematical computing, and orthogonal polynomials. Since 2012, he has been a founding core-team member of the open-source Dedalus project.