Interactions of Phase-Locked Waves in the Far Wake of a Cylinder

In this paper a low dimensional dynamical system is used to model the local evolution of a disturbance superimposed on a basic shear flow. In particular, nonlinear interactions between planar waves and oblique waves which travel phase-locked in the far wake of a cylinder are simulated. At this aim a low-dimensional dynamical system is derived by imposing the respect of a nonlinear truncation condition together with the phase-locked condition. The numerical results are compared with some recent experimental results obtained analysing the dynamics of a cylinder far wake. Different experimental conditions were modelled by dynamical systems defined by one or more coupled triadic systems. The energy spectral distribution of the numerical time histories of the streamwise velocity component well reproduce the experimental dynamics of the cylider far-wake. Also the numerical reconstruction of the streaklines shows a good agreement with the visualized flow field.