The wake of two oscillating cylinders in a tandem arrangement is a nonlinear system that displays Arnold tongues. We show by numerical simulations that their geometry depends on the phase difference $\theta$ between the two oscillating cylinders. At $\theta =0$ there may be holes inside these intraresonance regions unlike the solid Arnold tongues encountered in single-cylinder oscillations. This implies that, surprisingly, self-excitation of the system may be suppressed inside these holes, at conditions close to its natural frequency.

• Received 2 December 2004

DOI:https://doi.org/10.1103/PhysRevLett.96.014501