Low-power High Gain Observers for Wake Flow Rebuild
Abstract
This paper deals with the observation of the wake flow behind a bluff body based on reduced order models. Two Galerkin models with different truncation orders are considered to capture the intermittent character of the vortex shedding. The system output is the oscillation amplitude obtained thanks to pression measurements on the sides and on the back of the bluff body. For flow control purposes, the state estimation has to be efficient and robust to noises and dynamic changes. A high gain observer is modified i) by extending the state with the introduction of fictitious outputs in order to avoid an observability singularity and to ensure the existence of the inverse jacobian matrix and ii) by integrating a high gain parameter whose power is limited to 2 instead of n to address the sensitivity issue of the standard high gain observer. Simulation results illustrate the efficiency of the proposed observers and highlight promising applications for flow control at high Reynolds numbers.
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