Summary:

In this thesis, a review of closed-loop flow control is proposed. It focuses on two typical flow configurations: separated flow control and open cavity flow control. For separated flow control, closed-loop control is implemented on a NACA 4412 solid flap, using conventional actuators and sensors, respectively Festo valves and hot films. Two control laws are applied: one being data-based, leading to a linear integral controller, and the second being a phenomenological/model-based law, leading to the synthesis of a non-linear, positive integral controller. These laws enable the control of a disbonded flow to be implemented quickly and easily. The flow control on an open cavity, which is favourable to the use of MEMS actuators, is achieved using MMMS (Micro Magneto Mechanical Systems) microvalves integrated into the upstream wall of the cavity. Open- and closed-loop control tests are being carried out. For closed-loop control, linear controllers are designed using a structured H_infinite synthesis to dampen oscillations in the open cavity. In the final section, technological developments are proposed for both MEMS sensors and actuators with a view to future flow control tests on even more ambitious configurations.

Abstract:

In this dissertation, a review of closed-loop control of flows is proposed. It focuses on two typical flow configurations: control of disbonded flows and control of cavity flows. control of disbonded flows and control of open cavity flows. control. With regard to the control of separated flows, closed-loop control is control is implemented on a NACA 4412 type solid flap, using conventional conventional actuators and sensors, respectively Festo valves and and hot film. Two control laws are applied: one based on data, leading to a linear integral controller and the second being a phenomenological law, leading to the synthesis of a nonlinear, positive integral controller. positive integral controller. These laws allow the simple and rapid control of a disbonded flow. The control of flow over an open cavity, favourable to the use of MEMS actuators, is achieved using MMMS (Micro Magneto Mechanical Systems) microvalves integrated into the upstream upstream wall of the cavity. Open- and closed-loop control tests are carried out. For closed-loop control, linear controllers are designed using a structured H_infinite synthesis to dampen the oscillations of the open cavity. oscillations of the open cavity. In the final section, technological developments proposed for both MEMS sensors and actuators with a view to future control future flow control tests on even more ambitious configurations. more ambitious configurations.