Woodruff School of Mechanical Engineering
Dynamics, Geometry, and Topology of Fluid Turbulence
Dr. Roman Grigoriev
Georgia Institute of Technology
Tuesday, February 20, 2018 at 11:00:00 AM
MRDC Building, Room 4211
Dr. Devesh Ranjan
Dramatic progress in understanding fluid turbulence, especially at moderate Reynolds numbers, has been made in the past decade using a deterministic framework based on the state space geometry of unstable solutions of the Navier-Stokes equation. Initial results obtained by restricting attention to minimal flow units capable of sustaining turbulence and imposing unphysical (e.g., spatially periodic) boundary conditions seemed to suggest that fluid turbulence is in many ways similar to low-dimensional chaos, with unstable periodic solutions forming the geometric skeleton for dynamics. However, extending these results to larger flow domains with physical boundary conditions both proved very challenging and produced a number of surprises. In particular, our experimental and numerical studies have shown that unstable equilibria, quasiperiodic states, and heteroclinic connections can play an equally important role. We have also demonstrated that unstable solutions can be used for forecasting the evolution of experimental turbulent flows.
Roman Grigoriev received his MS in physics from Moscow State University and PhD from Caltech. He spent two years as a postdoctoral fellow at the University of Chicago before joining the School of Physics at Georgia Tech in 2000. Prof. Grigoriev's research group studies a variety of topics related to nonlinear dynamics and pattern formation in out-of-equilibrium systems. Some of his current research projects focus on deterministic models of fluid turbulence, phase change and heat transfer in fluids, and dynamical and topological description of cardiac arrhythmias.
Refreshments will be served.