Akademik Veri Yönetim Sistemi
37th AIAA Fluid Dynamics Conference, Miami, FL, Amerika Birleşik Devletleri, 25 - 28 Haziran 2007, cilt.3, ss.2420-2432
Feedback flow control on the wake of a circular cylinder at a Reynolds number of 100 is a challenging benchmark for controlling absolute instabilities associated with bluff body wakes. A two dimensional, high resolution simulation is used to develop low-dimensional models for estimator and controller design. Actuation is implemented as displacement of the cylinder normal to the flow. This control approach uses a low dimensional model based on a 15 mode Double Proper Orthogonal Decomposition (DPOD) applied to the velocity field. The control strategy involves the real-time estimation of the DPOD modes, obtained from a dynamic non-linear mapping algorithm using sensor readings, and a respective feedback command based on these estimates. Two control laws are developed. The first approach utilizes just a single mode feedback based on the fundamental von Kármán fluctuating DPOD mode. The second control law allows for dual inputs which include both the von Kármán fluctuating DPOD mode as well as its respective shift mode. The shift mode provides corrections for spatial variations in the POD Eigenfunctions which are caused by the feedback control-induced modification of the wake. The simulation results show that while both controller laws stabilize all 15 modes, the dual-input approach is more effective in reducing drag and fluctuating lift.