# A rapidly settled closed-loop control for airfoil aerodynamics based on plasma actuation

A rapidly settled closed-loop control for airfoil aerodynamics based on plasma actuation This paper presents an experimental investigation on the response of the slope seeking with extended Kalman filter (EKF) deployed in a closed-loop system for airfoil aerodynamics control. A novel dielectric barrier discharge (DBD) plasma actuator was used to manipulate the flow around the NACA 0015 airfoil. Experiments were performed under different freestream velocities U ∞, covering the chord Reynolds number Re from 4.4 × 104 to 7.7 × 104. Firstly, the advantages of applying this DBD plasma actuator (hereafter called sawtooth plasma actuator) on the airfoil were examined in an open-loop system at Re = 7.7 × 104. The sawtooth plasma actuator led to a delay in the stall angle α stall by 5° and an increase in the maximum lift coefficient $$C_{{{\text{L}}_{ \text{max} } }}$$ C L max by about 9 %. On the other hand, at the same input power, the traditional DBD plasma actuator managed a delay in α stall by only 3° and an increase in $$C_{{{\text{L}}_{ \text{max} } }}$$ C L max by about 3 %. Secondly, the convergence time t c of the lift force F L at Re from 4.4 × 104 to 7.7 × 104 was investigated for two closed-loop systems. It has been demonstrated that the t c was about 70 % less under the slope seeking with EKF than that under the conventional slope seeking with high-pass (HP) and low-pass (LP) filters at Re = 7.7 × 104. The reduction in t c was also observed at a different Re. Finally, the slope seeking with EKF showed excellent robustness over a moderate Re range; that is, the voltage amplitude determined by the control algorithm promptly responded to a change in Re, much faster than that of the conventional slope seeking with HP and LP filters. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experiments in Fluids Springer Journals

# A rapidly settled closed-loop control for airfoil aerodynamics based on plasma actuation

, Volume 56 (8) – Jul 24, 2015
15 pages

/lp/springer_journal/a-rapidly-settled-closed-loop-control-for-airfoil-aerodynamics-based-BwreqHnbfw
Publisher
Springer Berlin Heidelberg
Copyright © 2015 by Springer-Verlag Berlin Heidelberg
Subject
Engineering; Engineering Fluid Dynamics; Fluid- and Aerodynamics; Engineering Thermodynamics, Heat and Mass Transfer
ISSN
0723-4864
eISSN
1432-1114
D.O.I.
10.1007/s00348-015-2032-5
Publisher site
See Article on Publisher Site

### Abstract

This paper presents an experimental investigation on the response of the slope seeking with extended Kalman filter (EKF) deployed in a closed-loop system for airfoil aerodynamics control. A novel dielectric barrier discharge (DBD) plasma actuator was used to manipulate the flow around the NACA 0015 airfoil. Experiments were performed under different freestream velocities U ∞, covering the chord Reynolds number Re from 4.4 × 104 to 7.7 × 104. Firstly, the advantages of applying this DBD plasma actuator (hereafter called sawtooth plasma actuator) on the airfoil were examined in an open-loop system at Re = 7.7 × 104. The sawtooth plasma actuator led to a delay in the stall angle α stall by 5° and an increase in the maximum lift coefficient $$C_{{{\text{L}}_{ \text{max} } }}$$ C L max by about 9 %. On the other hand, at the same input power, the traditional DBD plasma actuator managed a delay in α stall by only 3° and an increase in $$C_{{{\text{L}}_{ \text{max} } }}$$ C L max by about 3 %. Secondly, the convergence time t c of the lift force F L at Re from 4.4 × 104 to 7.7 × 104 was investigated for two closed-loop systems. It has been demonstrated that the t c was about 70 % less under the slope seeking with EKF than that under the conventional slope seeking with high-pass (HP) and low-pass (LP) filters at Re = 7.7 × 104. The reduction in t c was also observed at a different Re. Finally, the slope seeking with EKF showed excellent robustness over a moderate Re range; that is, the voltage amplitude determined by the control algorithm promptly responded to a change in Re, much faster than that of the conventional slope seeking with HP and LP filters.

### Journal

Experiments in FluidsSpringer Journals

Published: Jul 24, 2015

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