Journal of Fluid Mechanics

Three-dimensional Floquet stability analysis of the wake of a circular cylinder

Dwight  Barkley a1 and Ronald D.  Henderson a2
a1 Nonlinear Systems Laboratory, Mathematics Institute. University of Warwick, Coventry, CV4 7AL, UK
a2 Aeronautics and Applied Mathematics, California Institute of Technology, Pasadena, CA 91125, USA

Article author query
barkley d   [Google Scholar] 
henderson rd   [Google Scholar] 


Results are reported from a highly accurate, global numerical stability analysis of the periodic wake of a circular cylinder for Reynolds numbers between 140 and 300. The analysis shows that the two-dimensional wake becomes (absolutely) linearly unstable to three-dimensional perturbations at a critical Reynolds number of 188.5±1.0. The critical spanwise wavelength is 3.96 ± 0.02 diameters and the critical Floquet mode corresponds to a ‘Mode A’ instability. At Reynolds number 259 the two-dimensional wake becomes linearly unstable to a second branch of modes with wavelength 0.822 diameters at onset. Stability spectra and corresponding neutral stability curves are presented for Reynolds numbers up to 300.

(Received March 20 1995)
(Revised April 16 1996)