Department of Aerospace Engineering, University of Glasgow
Abstract
This report is a summary of research conducted for the EPSRC on contract GR/L/59030— “Low-dimensional characterization and control of bluff-body wakes”. The motivation for the work was to investigate active control schemes for stabilizing the low-Reynolds number bluff-body wake, which is an archetypal unstable flow exhibiting self-sustained flow oscillations as a result of global flow instability. Control of bluff-body wake oscillations is of use in drag reduction, noise suppression and prevention of flow induced structural oscillations. Moreover, suppression of closely related unstable flows, such as growth of a dynamic stall vortex on a pitching helicopter blade, may be possible using a similar strategy. To this end, a numerical model of an unstable bluff-body flow was developed and validated by comparison with published literature. Various control strategies involving low-dimensional models of the flow and combinations of distributed sensors and actuators in the near and far wake were investigated. The control results of this study are unique, in that successful control of the flow has been demonstrated further away from criticality than by any other scheme. These results provide a base for continued research in this area and in other related flows (for instance control of helicopter dynamic stall) and has contributed to a publication [1] and several others in preparation
