Overview
Active flow control by means of pulsed blowing has proven to be effective and efficient to delay or avoid flow separation on aerodynamic bodies and therefore increases their operating range. Such active flow control systems, however, require effective, efficient and reliable flow control actuators, the design and validation of which is the aim of the proposed project.
Based on previous work on fluidic actuators at TUB, the most promising starting point for the development of a large scale actuator was chosen. Once this concept was finalised, numerical studies were used to optimize the inner shape of the fluidic switches and actuator chambers, as well as the air routing towards the fluidic actuators. The most promising actuator designs were then provided as input for an advanced fluidic actuator design process, during which several prototypes were produced and tested, using pressure and particle image velocimetry measurement techniques, to further enhance the actuators’ performance. The experimental design process also comprised the integration of single element fluidic actuators into actuator arrays, each of which can be driven by one centrally generated pneumatic control signal.
After the design freeze, a mock-up was manufactured as a subsystem demonstrator and its performance was investigated thoroughly. The fluidic actuator was then downscaled to fit into the flap of a large scale wind tunnel model as described in the CfP. A prototype of this downscaled actuator was manufactured, its performance was documented and the prototype was supplied to a SFWA partner.
Funding
Results
Executive Summary:
Active flow control by means of pulsed blowing has proven to be effective and efficient to delay or avoid flow separation on aerodynamic bodies and therefore increases their operating range. Such active flow control systems, however, require effective, efficient, and reliable flow control actuators, the design and validation of which was the aim of the project DT-FA-AFC. Different flow control actuator concepts have been the focus of research in the past decades. The variety ranges from piezo-driven Zero-Net-Mass-Flux (ZNMF) actuators, plasma based actuators, and mechanical valves to pyrotechnic actuator and moving pistons. The control authority and frequency range of those actuators vary greatly, all have their pros and cons, and all concepts were tested more or less extensively in lab scale experiments. Only very few concepts reached the maturity level to be flight tested and no concept was ever considered for commercial (civil) application.
Within the frame of DT-FA-AFC it was attempted to develop a core flow control actuator system that has the potential to be considered for commercial, civil application. In the course of the project an aircraft scale fluidic actuator system was devised that produces high amplitude pulsed air jets without incorporating any moving or electrical components. The system performance was evaluated (in close cooperation with SFWA project FloCoSys) in bench-top experiments. Its design was provided to SFWA project AFCIN to study the integrability into a trailing edge flap modified for AFC application. The combined findings of DT-FA-AFC, FloCoSys, and AFCIN show that it is possible to design an actuator system for active flow control that is capable of providing the necessary control authority in a relevant frequency range, while being sufficiently robust und compact to be considered for integration in a civil airliner.