MS37 ~ Wednesday, May 24, 1995 ~ 10:00 AM

Non-Normal Dynamics: Instability without Unstable Modes

This minisymposium expands upon the theme introduced in the invited talk by Brian Farrell: the behavior of dynamical systems that couple large linear, non-modal effects with typically smaller nonlinear effects. Such systems include most fluid flows at high Reynolds numbers, with applications in engineering, meteorology, and geophysics. In the past five years, it has become recognized that an understanding of linear, non-modal phenomena is essential to a full understanding of such systems. The speakers will present some current results in the ongoing attempt to work out the details of this picture as applied to certain topics including hydrodynamic stability, transition to turbulence, and fully-developed turbulence.

Organizer: Lloyd N. Trefethen, Cornell University

Spectra and Pseudospectra for Pipe and Channel Flows
Lloyd N. Trefethen, Organizer
The Interaction of Random Nonlinearities with Linear, Non-modal Effects
Jeffrey S. Baggett, Cornell University
Thresholds for Transition to Turbulence in Channel Flows
Satish C. Reddy, Oregon State University
Using Non-Normal Dynamics to Actively Control Shear Turbulence
Petros J. Ioannou, Massachusetts Institute of Technology