Flow control using automatic differentiation and synthetic jets

Abstract

Flow control over the circular cylinder at Reynolds 42.000 and Mach = 0.2 is analyzed using controls like synthetic jet actuators. Such actuators are defined by their operating frequency and top blowing/suction speed and are located on the rear surface of the cylinder and they can be operated individually or as arrays. The analysis is based on CFD techniques and control theory. Taking drag as a cost function, minimization of drag oscillations is achieved using an optimal control algorithm where automatic differentiation of the RANS solver is used in order to generate the gradient. Results are presented for the numerical simulation of the actuator and the flow around the cylinder using active flow control.