Zaccara, Mirko (2022) Experimental investigation of wingtip vortices control with synthetic jets. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Resource language: English
Title: Experimental investigation of wingtip vortices control with synthetic jets
Creators:
CreatorsEmail
Zaccara, Mirkomirko.zaccara@unina.it
Date: 14 March 2022
Number of Pages: 148
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Industriale
Dottorato: Ingegneria industriale
Ciclo di dottorato: 34
Coordinatore del Corso di dottorato:
nomeemail
Grassi, Michelemichele.grassi@unina.it
Tutor:
nomeemail
Cardone, GennaroUNSPECIFIED
Greco, Carlo SalvatoreUNSPECIFIED
Date: 14 March 2022
Number of Pages: 148
Keywords: synthetic jet; wingtip vortices; flow control; PIV
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-IND/06 - Fluidodinamica
Date Deposited: 30 Mar 2022 12:03
Last Modified: 28 Feb 2024 10:59
URI: http://www.fedoa.unina.it/id/eprint/14416

Collection description

Wingtip vortices are proven to be detrimental to both aircraft efficiency and safety due to their adverse effects such as wake hazard, blade vortex interaction (BVI) noise, and induced drag. Despite the extensive literature on the subject, the number of experimental works featuring far field velocity measurements under active control are very limited. The present thesis presents the experimental investigation of the effectiveness of synthetic jet actuation control on the wingtip vortices and their wake hazard. In order to preserve the mutual induction of the counter-rotating vortices during their evolution, an unswept, low aspect ratio, squared-tipped, finite-span wing is employed. The synthetic jet actuation is based on triggering the inherent instabilities of Crow and Widnall at different momentum coefficient Cμ with the goal to reduce the vortices strength, the induced circumferential velocity, and to obtain an anticipated vortices break up. Different exit geometries of the synthetic jet have been tested to analyze the effects of the jet velocity and jet position changes on the wingtip vortices. A proper phase-locked stereoscopic particle image velocimetry setups have been designed to carry out such a parametric study in the near and far wake at a distance from the wing trailing edge up to 2 and 80 chord lengths, respectively. The effects of blowing at high momentum coefficient Cμ=1% are demonstrated to be remarkable on the wingtip vortices mitigation but the implementation of this control configuration on a real-scaled wing could be unfeasible. On the other hand, both the time and phase-averaged results suggest that, at relatively low value of Cμ=0.2%, using a larger synthetic jet exit section area allows to greatly affect the wingtip vortices features causing a striking alleviation of the vorticity distribution up to 90% with respect to the baseline reference case. As a matter, due to the actuation at low frequency, the vortices instability is prematurely risen up and amplified, leading to an early vortices linking and their consequent dissipation.

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