Boundary-Layer Stabilization with Dielectric Barrier Discharge Plasmas for Free-Flight Application

• Main Author: Duchmann, Alexander
• Format: Others
• Language: German; en
• Published: 2012
• Online Access: https://tuprints.ulb.tu-darmstadt.de/3351/7/DissDuchmann.pdf; Duchmann, Alexander <http://tuprints.ulb.tu-darmstadt.de/view/person/Duchmann=3AAlexander=3A=3A.html> (2012): Boundary-Layer Stabilization with Dielectric Barrier Discharge Plasmas for Free-Flight Application.Darmstadt, Technische Universität, [Ph.D. Thesis]

The present work combines experimental and numerical efforts to enhance the maturity of dielectric barrier discharge (DBD) plasma actuators as flow-control devices. In an attempt to increase the effectiveness of controlling laminar-turbulent transition, the understanding of a stabilizing effect of the actuator force field on laminar boundary-layer flow is fostered. Parametrical studies extend the Reynolds number range for effective transition control beyond the limits of earlier investigations. A numerical tool kit, consisting of a boundary-layer solver with implemented DBD force model and coupled stability analysis, is developed to predict the flow-control effectiveness. Validation experiments show considerable transition delay in a wind-tunnel setting. The excellent agreement of the experimental data with the numerical predictions renders the latter valuable for the design of flow-control applications. In order to realize an application of plasma actuators under non-laboratory conditions, a transition control experiment is designed for in-flight application on a full-sized motorized glider. The performed proof-of-concept experiment at a Reynolds number of 3000000 is the first to show a successful use of DBD transition control under atmospheric flight conditions. The discussion of the significantly delayed transition and resulting drag reduction concludes with an estimate for the flow-control efficiency.