Technique for Enhanced Flow Control Efficiency Through Thermal Actuation

Abstract

Thermal active flow control has been developed to enhance the efficiency of active flow control systems. The actuation concept is derived from gas-dynamics principles, and it is based on thermal control of the air supply. It is shown that higher air supply temperatures result in reduced mass flow rate with no degradation in active flow control performance. A computational method has been used to systematically investigate the hot air supply approach for isolated blowing actuators and fluidic oscillators. Subsequently, the thermal control concept has been computationally evaluated for airplane applications. These include enhanced control authority of a vertical tail and an airplane high-lift system, confirming the trends observed from the gas-dynamics analysis with regard to reduced actuation input as a function of supply temperature. Further confirmation of the thermal actuation concept was experimentally obtained for a bench-top actuator and a vertical-tail model in a wind-tunnel setting. The paper introduces potential approaches for system integration associated with heated supply, while highlighting the benefit of using available high-temperature sources for active flow control.