A. Seifert, G. Arwatz

Active flow control (AFC), the capability to alter a flow state, relies on the control authority of the actuators as a primary enabling technology. Unsteady zero-net-mass-flux (ZNMF) periodic excitation was proven to be significantly more effective than steady blowing and simpler to apply than steady suction for the control of boundary layer separation. Furthermore, it can utilize flow instability as efficiency magnifier and has a bandwidth that is suitable for closed-loop control. However, the current state-of-the-art ZNMF actuators lack, for many applications, sufficient control authority. Therefore, effective methods for coupling the excitation to the most unstable modes of the flow preferably be sought after and utilized. Three-dimensional excitation modes should be explored, as the flow naturally turns 3D even if the baseline flow and the excitation are nominally two-dimensional. Overall system efficiency should always be considered, not only the improvement in aerodynamic performance. A new robust and simple actuator concept that relies on bleed air to operate will be presented. It can generate oscillatory excitation in the range of 10Hz to several kHz and excitation velocities of near sonic speeds. The performance of a cm size device will be presented and prototype MEMS devices will also be presented. The unique design of the valve allows it to be extremely effective, therefore does not nullify the favorable effects of the AFC scheme.

CEAS/KATnet Conference on Key Aerodynamic Technologies, Bremen, 2005

Conference Paper

englisch

21,0 x 29,7 cm, 8 Seiten

DGLR-Bericht, 2005, 2005-07, CEAS/KATnet Conference on Key Aerodynamic Technologies - Proceedings; S.1-8; 2005; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

in getr. Zählung;

aerodynamics

Bibliothek

2005