Deterministic and stochastic analyses of the lock-in phenomenon in vortex-induced vibrations

The phenomenon of lock-in in vortex-induced vibrations of bluff bodies is studied from a phenomenological model perspective. The theoretical investigation includes asymptotic deterministic and stochastic analyses which are compared with experimental measurements and Monte-Carlo simulations. It is shown that, for the considered parameter space, the model can possess only a single or multiple (co-existing) synchronized solutions, where the stable synchronized solution is hardly affected by the turbulence-induced random fluctuations far from the bifurcation points. These results provide a relatively simple connection between experimental measurements and the model predictions, and they confirm the validity of the phenomenological model for vortex-induced vibrations problems that involve a turbulent wake.