Subharmonic resonance of Venice gates in waves. Part 2. Sinusoidally modulated incident waves (Subharmonic resonance of Venice gates in waves. Part 2)

In order to examine the effects of finite bandwidth of the incident sea spectrum on the resonance of the articulated storm gates for Venice Lagoon, we consider a narrow band consisting of the carrier frequency and two sidebands. The evolution equation for the gate oscillations now has a time-periodic coefficient, and is equivalent to a non-autonomous dynamical system. For small damping and weak forcing, approximate analysis for local and global bifurcations are carried out, and extended by direct numerical simulation. Typical bifurcation scenarios are also examined by laboratory experiments.