Instabilities in Fluid Motion

12:30
PM-1:15 PM

*Room: Capitol Center/South*

*Chair: Barbara L. Keyfitz, University of Houston*

The issue of stability/instability of fluid flows presents an important example of a physical problem which may be addressed through sophisticated mathematical techniques. The answers have direct physical interpretations: stable flows are robust under inevitable disturbances in the environment while unstable flows may break up rapidly. The question of stability/instability of a fluid flow is a classical one, however there remain many open problems that are mathematically challenging. In this presentation, the speaker will introduce the concept of a "fluid Lyapunov exponent" and describe an effective sufficient condition for detecting instabilities in an inviscid fluid. She will discuss a recent result which proves that under certain conditions, linear instability implies nonlinear instability. This is joint work with Walter Strauss and Misha Vishik.

**Susan Friedlander**

*Department of Mathematics*

*University of Illinois, Chicago*

*MMD, 4/22/99*