Computational and Applied Math Proseminar

Friday, December 1, 1:40 p.m. GWC 604

Marc Avila Cañellas

Dept. Appl. Physics, Polytechnic University of Catalonia

Centrifugal Instability In Harmonically Forced Flows

Abstract Harmonic forcing of physical systems can be used as a mechanism to stabilize otherwise unstable states or vice versa. For example, a rigid pendulum in the upside-down position can be stabilized by periodically moving the suspension point of the pendulum up and down. However, in spatially extended systems a time periodic forcing may simultaneously stabilize and destabilize different spatial modes.

In this seminar, we will discuss the effect of different harmonic forcings in a fliud system where the source of instability is the centrifugal force. The physical model selected, fluid confined between to spinning cylinders, is precisely reproduced in laboratory experiments and can be numerically simulated very accurately. In order to examine both the efficiency in delaying transition and the effects on the spatio-temporal dynamics in this system, Floquet analysis of the resulting time-periodic flows has been combined with spectral nonlinear computations. Moreover, the results will be compared with the unforced case focusing on the spatial and temporal complexity of the computed solutions.

For further information please contact: mittelmann@asu.edu