MODELING OF A VONKARMAN VORTEX STREET AT LOW REYNOLDS-NUMBERS

Time signals of transient von Karman vortex streets are represented as trajectories in a two-dimensional state space for Reynolds numbers between 53 and 148. From this representation, a two-dimensional system of ordinary differential equations with ten coefficients is derived and used as a model for the description of the asymptotic dynamics, Most of these coefficients are only slightly dependent on the Reynolds number, and some of them also reflect the change in vortex shedding dynamics. With the obtained low-dimensional model, the response of the vortex street to external sinusoidal and square wave signals is predicted. Furthermore, it is shown that an excessively large excitation of the vortex street by sound can lead to a more complicated higher-dimensional dynamical state.