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

Duchmann, Alexander (2012):
Boundary-Layer Stabilization with Dielectric Barrier Discharge Plasmas for Free-Flight Application.
Darmstadt, TU Darmstadt, [Online-Edition: http://tuprints.ulb.tu-darmstadt.de/3351],
[Ph.D. Thesis]

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.

Item Type: Ph.D. Thesis
Erschienen: 2012
Creators: Duchmann, Alexander
Title: Boundary-Layer Stabilization with Dielectric Barrier Discharge Plasmas for Free-Flight Application
Language: English
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.

Place of Publication: Darmstadt
Uncontrolled Keywords: DBD, Plasma Actuator, Boundary Layer, Flow Control
Divisions: 16 Department of Mechanical Engineering > Fluid Mechanics and Aerodynamics (SLA)
16 Department of Mechanical Engineering
Date Deposited: 19 May 2013 19:55
Official URL: http://tuprints.ulb.tu-darmstadt.de/3351
URN: urn:nbn:de:tuda-tuprints-33513
License: Creative Commons: Attribution-No Derivative Works 3.0
Referees: Tropea, Prof. Cameron and Dan, Prof. Henningson
Refereed / Verteidigung / mdl. Prüfung: 17 December 2012
Alternative Abstract:
Alternative abstract Language
Die vorliegende Arbeit kombiniert experimentelle und numerische Untersuchungen zur Strömungskontrolle mit dielektrischen Barriereentladungs-Plasma Aktuatoren. Um die Effektivität der Kontrolle des laminar-turbulenten Umschlags zu steigern wird das Verständnis für den stabilisierenden Effekt des Aktuator-Kraftfeldes auf laminare Grenzschichtströmungen verbessert. Parameterstudien erweitern den Reynoldszahlbereich, innerhalb dessen eine effektive Kontrolle der Transition möglich ist, jenseits der Grenzen vorheriger Untersuchungen. Ein numerisches Werkzeug, bestehend aus einem Grenzschicht-Löser mit integriertem Modell eines Plasma-Aktuators und gekoppelter Stabilitätsanalyse, dient zur Vorhersage der Kontrolleffektivität. Validierungsexperimente im Windkanal zeigen eine erhebliche Verzögerung der Transition. Die hervorragende Übereinstimmung der experimentellen Daten mit numerischen Vorhersagen ermöglicht die Verwendung der letztgenannten zur Auslegung von Strömungskontrollanwendungen. Um eine Anwendung von Plasma-Aktuatoren ausserhalb laboratorieller Bedingungen zu realisieren wird ein Freiflug-Experiment zur Transitionskontrolle auf einem Motorsegler gestaltet. Die Machbarkeitsstudie bei einer Reynoldszahl von 3000000 zeigt erstmals eine erfolgreiche Anwendung von Plasma-Aktuatoren zur Transitionskontrolle unter atmosphärischen Flugbedingungen. Eine abschliessende Diskussion der Transitionsverzögerung und der ermöglichten Reibungsreduktion resultiert in einer Abschätzung der Strömungskontrolleffizienz. German
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