Active Flow Control Applied to Military and Civil Aircraft

Abstract

There are essentially two aspects to the application of active flow control: Firstly, the improvement of aircraft performance otherwise restricted by the development of the boundary layer and the interaction of the boundary layer with the outer "inviscid" flow field, exacerbated at high speed by the occurrence of shock waves which considerably increase aircraft drag; secondly, the direct control of the aircraft geometry to adjust to changing flight or freestream conditions for optimized performance at all points of the flight envelope. In the present paper both aspects are being considered and flow control and adaptive-wing concepts for military and civil air vehicle applications discussed. Examples for each control objective are provided and benefits associated with implementing adaptive-wing and flow-control technologies outlined. The discussion is based on results from the literature and results of two recent projects, namely, the German national adaptive-wing project ADIF and the EU-project EUROSHOCK II, the latter concerned with boundary layer and shock control. Main emphasis is being placed on aerodynamics.