Real-time feedback control of flow velocity field using sparse processing particle image velocimetry and plasma actuators

Abstract Visual feedback control of a flow field by a controller that operates plasma actuators with sparse processing particle image velocimetry as an observer was implemented in a wind tunnel test. The control objective was the suppression of a Kàrmàn vortex around a circular cylinder. Sum-of-absolute-values control based on an $$L_1$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>L</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:math> optimization problem was implemented to enable real-time processing. Real-time visual feedback control at 2000 Hz was achieved with the proposed system owing to the use of sparse processing particle image velocimetry, which evaluates only a limited number of interrogation windows, and a sophisticated solver for the $$L_1$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>L</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:math> optimization problem. The techniques adopted in the present study can accelerate the feedback control rate by a factor of 10 to 100. It was confirmed that the proposed system suppresses the Kàrmàn vortex to a certain extent. The results show that the control law using forecasts further ahead performs better.