Vortex Lock-on and Flow Control in Bluff Body Near-Wakes

Abstract

The results of recent experiments show the concept of universal vortex wake similitude to be more general than was previously supposed. In this paper these similarity arguments are directed as an example to the case of vortex lock-on in oscillatory flow. This form of vortex lock-on exhibits a particularly strong resonance between the flow perturbations and the vortices, and provides one potential means for modification and control of the basic formation and stability mechanisms in the near-wake. The essential features of active and passive wake control by means of body oscillations and geometrical alterations are discussed briefly. Then the stability characteristics of the near-wake, i.e. absolute versus convective, are considered in terms of recent computations and experiments. As an example, the flow in the vortex formation region has been shown to be absolutely unstable to small disturbances.KeywordsCircular CylinderDirect Numerical SimulationStrouhal NumberBluff BodyVortex StreetThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.