Comprehensive characterization of a pneumatic active flow control system using in-situ hot wire calibration

Pneumatic active flow control systems have great potential to control the aerodynamic phenomena including, separation, circulation, and turbulence. To quantify the effectiveness of such flow control schemes, thorough characterization of developed systems is critical in addition to estimating aerodynamic and stability favor. In the present work, experimental characterization of an in-house active blowing system capable of steady and periodic excitations, based on fast switching solenoid valves, is presented via in-situ calibration scheme. Measurements are performed using a constant temperature anemometry system, and characterization is presented for a sample 45o swept delta wing aerodynamic surface. The performance of the developed system is comprehensively investigated for a square wave form excitation with control parameters including an excitation frequency range of 1-32 Hz, duty cycle values of 25 and 50 %, and supply line regulator settings corresponding to supply rate range of 34 m/s <= Ublow,ref <= 60 m/s. The results indicate that the response of the flow control system to control signals is influenced by both the signal parameters and the aerodynamic surface design. Full characterization of such systems using in-situ approaches provides valuable calibration schemes for the mentioned parameters, which is crucial for assessing aerodynamic effectiveness and developing closed-loop flow control systems.