Linear models for control of cavity flow oscillations

Clarence Worth Rowley, David R. Williams, Tim Colonius, Richard M. Murray, Douglas G. Macmynowski

Research output: Contribution to journalArticlepeer-review

80 Scopus citations

Abstract

Models for understanding and controlling oscillations in the flow past a rectangular cavity are developed. These models may be used to guide control designs, to understand performance limits of feedback, and to interpret experimental results. Traditionally, cavity oscillations are assumed to be self-sustained: no external disturbances are necessary to maintain the oscillations, and amplitudes are limited by nonlinearities. We present experimental data which suggests that in some regimes, the oscillations may not be self-sustained, but lightly damped: oscillations are sustained by external forcing, such as boundary-layer turbulence. In these regimes, linear models suffice to describe the behaviour, and the final amplitude of oscillations depends on the characteristics of the external disturbances. These linear models are particularly appropriate for describing cavities in which feedback has been used for noise suppression, as the oscillations are small and nonlinearities are less likely to be important. It is shown that increasing the gain too much in such feedback control experiments can lead to a peak-splitting phenomenon, which is explained by the linear models. Fundamental performance limits indicate that peak splitting is likely to occur for narrow-bandwidth actuators and controllers.

Original languageEnglish (US)
Pages (from-to)317-330
Number of pages14
JournalJournal of Fluid Mechanics
Volume547
DOIs
StatePublished - 2006

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'Linear models for control of cavity flow oscillations'. Together they form a unique fingerprint.

Cite this