The two-dimensional stationary flow past a rotating cylinder is analyzed for both two and three-dimensional perturbations. The instability mechanisms for the high and low- frequency modes are analyzed and the complete neutral curve presented. It is shown that the first bifurcation in the case of the rotating cylinder occurs for stationary three- dimensional perturbations, confirming recent experiments. Interestingly, the critical Reynolds number at high rotation rates is lower than the one for the stationary circular cylinder. The spatial characteristics of the disturbance and a qualitative comparison with the re- sults obtained for linear flows suggest that the stationary unstable three-dimensional mode could be of a hyperbolic nature.
Three-dimensional instability of the flow around a rotating circular cylinder
PRALITS, JAN OSCAR;
2013-01-01
Abstract
The two-dimensional stationary flow past a rotating cylinder is analyzed for both two and three-dimensional perturbations. The instability mechanisms for the high and low- frequency modes are analyzed and the complete neutral curve presented. It is shown that the first bifurcation in the case of the rotating cylinder occurs for stationary three- dimensional perturbations, confirming recent experiments. Interestingly, the critical Reynolds number at high rotation rates is lower than the one for the stationary circular cylinder. The spatial characteristics of the disturbance and a qualitative comparison with the re- sults obtained for linear flows suggest that the stationary unstable three-dimensional mode could be of a hyperbolic nature.
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