Closed-Loop Feedback Control of Flow Over a Flapped Airfoil at High Angles of Attack Using Identified NARMAX Model

This study investigates closed-loop feedback control system design aimed at reduction of turbulent flow separation over a NACA 0015 airfoil having 30% integral type trailing edge flap and equipped with leading-edge and trailing edge synthetic jet actuators (SJAs). The multiple-input single-output controller employs system identification techniques based on Nonlinear Auto Regressive Moving Average with eXogenous inputs (NARMAX) method to model nonlinear dynamics of the flow. RANS FLUENT simulations for 2-D airfoil are used besides an analytical modeling for the set of synthetic actuators. The resulting closed loop response using NARMAX tracks the desired pressure value and significant improvement in the transient response over the open-loop system at high angles of attack is realized. Improvements in aerodynamic efficiency and maximum lift values through active flow control would lead to better performance characteristics of airplanes.