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Experimental assessment of spanwise‑oscillating dielectric electroactive surfaces for turbulent drag reduction in an air channel flow

Gatti, Davide; Güttler, Andreas; Frohnapfel, Bettina; Tropea, Cameron

In the present work, wall oscillations for turbulent skin friction drag reduction are realized in an air turbulent duct flow by means of spanwise-oscillating active surfaces based on dielectric electroactive polymers. The actuator system produces spanwise wall velocity oscillations of 820 mm/s semi-amplitude at its resonance frequency of 65 Hz while consuming an active power of a few 100 mW. The actuators achieved a maximum integral drag reduction of 2.4 %. The maximum net power saving, budget of the power benefit and cost of the control, was measured for the first time with wall oscillations. Though negative, the net power saving is order of magnitudes higher than what has been estimated in previous studies. Two new direct numerical simulations of turbulent channel flow show that the finite size of the actuator only partially explains the lower values of integral drag reduction typically achieved in laboratory experiments compared to numerical simulations.

DOI: 10.1007/s00348-015-1983-x
Zitationen: 7
Web of Science
Zitationen: 4
Seitenaufrufe: 89
seit 26.04.2018
Zugehörige Institution(en) am KIT Institut für Strömungsmechanik (ISTM)
Publikationstyp Zeitschriftenaufsatz
Jahr 2015
Sprache Englisch
Identifikator ISSN: 0723-4864
KITopen-ID: 1000054195
Erschienen in Experiments in Fluids
Band 56
Heft 5
Seiten Art.Nr. 110
Nachgewiesen in Web of Science
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