Duchmann, Alexander (2012)
Boundary-Layer Stabilization with Dielectric Barrier Discharge Plasmas for Free-Flight Application.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication

Abstract

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.

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