Closed-loop control of leading-edge and tip vortices for small UAV
T. Colonius, C. W. Rowley, G. Tadmor, D. R. Williams, K. Taira, W. B. Dickson, M. Gharib, and M. Dickinson
Proceedings of the First Berlin Conference on Active Flow Control , September 2006.
We present plans and preliminary results for a recently initiated multidisciplinary research effort aimed at closed-loop control of three-dimensional leading edge and tip vortices on low aspect ratio wings relevant to micro and small unmanned air vehicles. The goal of control is to extend the parameter space for which steady lift can be maintained at high angles of attack and to regulate leading edge and tip vortex formation to improve maneuverability and gust response. Initial efforts toward model-based control design and sensor-actuator configuration are presented. Dynamically dominant modes will be identified by integrating proper orthogonal decomposition (POD) and balanced truncation, and tunable empirical models will be based on energy exchange between the mean flow and POD modes and the addition of shift modes to track structures along natural and controlled transients. Plans for experimental and computational cross-validations of closed-loop control strategies are discussed, and preliminary results assessing actuator authority are presented. The differing stability characteristics of a leading-edge vortex in two-dimensional computations and finite-aspect ratio three-dimensional experiments are also highlighted.
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