Numerical simulation of a cylinder far wake

摘要

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, non-linear 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 those phase-locked condition experimentally observed. 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 stream-wise velocity component well reproduce the experimental dynamics of the cylinder far-wake. Also the numerical reconstruction of the streaklines shows a good agreement with the visualised flow field.