Kévin Mariette defends his PhD on Nov. 09, 2020 at 10:00 AM.
Place : visio conference only. [917 8028 1954 - 05JBxH],
Jury :
Rapporteurs : BRAUD Caroline, POLYAKOV Andrey
Examinateurs : QUEINNEC Isabelle, KOURTA Azeddine, BOREE Jacques
Directeur de thèse : BIDEAUX Eric (Ampère)
Co-encadrants de thèse: EBERARD Damien, BRIBIESCA-ARGOMEDO Federico, SESMAT Sylvie (Ampère)
Invité : CASTELAIN Thomas
Abstract :
Active flow control techniques can decrease the aerodynamic drag acting on a vehicle moving at high velocity. Instead of exclusively passive techniques, active control can reduce the pressure drag on a vehicle under a wider range of operating conditions without requiring large modifications of the functional shape of the vehicles. However, active control devices require an additional source of energy, which may decrease the global efficiency of the control. Our work aims to reduce significantly the drag of ground vehicles with efficiency and robustness thanks to high frequency pulsed jet control. We present experimental studies on a simplified bluff body mock-up of a ground vehicle and we seek to understand the phenomena linked to the pressure drag on a vehicle. In this thesis, we propose a modelling methodology of the vehicle’s turbulent wake adapted for control purposes. Finally, we design and test experimentally different closed-loop control methods of the wake with high frequency pulsed air jets. The experimental studies performed in a wind tunnel show the efficient application of sliding mode control and extremum seeking techniques for a robust drag control with energy cost considerations. This thesis was financed by the French National Research Agency (ANR) and contributes to the project ActivRoad involving three French laboratories: Ampère (INSA, Lyon), Pprime Institute (ENSMA, Poitiers), and the LMFA (Centrale, Lyon); and two automotive companies: PSA group and Volvo Trucks.
Key Words : Active flow control, drag reduction, extremum seeking, pulsed air jets, modelling, nonlinear closed-loop control
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