Cavity flow control simulations and experiments

Feedback control is used to suppress oscillations in the subsonic flow past a rectangular cavity. A heuristic feedback law is introduced into 2D direct numerical simulations, using zero-net-mass forcing at the leading edge of the cavity and a pressure sensor at the wall, and the oscillations are reduced by -13 dB. Reduced-order models are obtained from full-order direct numerical simulations, and used to design observers to reconstruct the full flow information from a single pressure measurement at the wall, and these observers are shown to be more effective than Linear Stochastic Estimation (LSE), which is commonly used for this purpose. Initial results of a new experiment are also given, and a model for designing zero-net-mass actuators with a desired bandwidth is presented, along with experimental data which supports the model predictions.