Parallel vortex body interaction enabled by active flow control

Weingaertner, Andre; Tewes, Philipp; Little, Jesse

doi:10.1007/s00348-020-02962-2

Cited by 8 publications

(3 citation statements)

References 28 publications

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“…Other works in the literature [10,11,13] presented flow separation as a result of parallel BVI, also in the case of highly loaded airfoil only, already close to the stall conditions. The behaviour of the interaction in those cases, however, differed from the present as it triggered a separation bubble in the leading edge region, which then propagated downstream.…”

Section: Vortex Interaction-static Airfoilmentioning

confidence: 78%

“…In recent times, particular attention has been brought to the topic of perpendicular BVI, as several studies, both experimental and numerical [6][7][8][9], on oscillating blades reported that an interaction of this kind can be the triggering source of dynamic stall of the blade, with a significant detrimental effect on the performances of the airfoil. On the other hand, the research on parallel BVI has mostly been limited to static airfoil models, and highlighted issues with flow separation only in the case of an airfoil at a very high incidence [10][11][12][13]; studies of vortex interaction with oscillating bodies have been focused on leading edge impingement or on the behaviour of periodic vortex patterns [5], rather than on the loads generated.…”

Section: Introductionmentioning

confidence: 99%

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Wind Tunnel Experiments on Parallel Blade–Vortex Interaction with Static and Oscillating Airfoil

Colli,

Zanotti,

Gibertini

2024

Fluids

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This study aims to experimentally investigate the effects of parallel blade–vortex interaction (BVI) on the aerodynamic performances of an airfoil, in particular as a possible cause of blade stall, since similar effects have been observed in literature in the case of perpendicular BVI. A wind tunnel test campaign was conducted reproducing parallel BVI on a NACA 23012 blade model at a Reynolds number of 300,000. The vortex was generated by impulsively pitching a second airfoil model, placed upstream. Measurements of the aerodynamic loads acting on the blade were performed by means of unsteady Kulite pressure transducers, while particle image velocimetry (PIV) techniques were employed to study the flow field over the blade model. After a first phase of vortex characterisation, different test cases were investigated with the blade model both kept fixed at different incidences and oscillating sinusoidally in pitch, with the latter case, a novelty in available research on parallel BVI, representing the pitching motion of a helicopter main rotor blade. The results show that parallel BVI produces a thickening of the boundary layer and can induce local flow separation at incidences close to the stall condition of the airfoil. The aerodynamic loads, both lift and drag, suffer important impulsive variations, in agreement with literature on BVI, the effects of which are extended in time. In the case of the oscillating airfoil, BVI introduces hysteresis cycles in the loads, which are generally reduced. In conclusion, parallel BVI can have a detrimental impact on the aerodynamic performances of the blade and even cause flow separation, which, while not being as catastrophic as in the case of dynamic stall, has relatively long-lasting effects.

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Section: Vortex Interaction-static Airfoilmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Wind Tunnel Experiments on Parallel Blade–Vortex Interaction with Static and Oscillating Airfoil

Colli,

Zanotti,

Gibertini

2024

Fluids

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“…2019 ), generating coherent structures (Jukes and Choi 2013 ; Weingaertner et al. 2020 ), turbulent boundary layer conditioning (Jacob et al. 2004 ; Schatzman and Thomas 2010 ), transition delay (Grundmann and Tropea 2008 ; Kotsonis et al.…”

Section: Introductionmentioning

confidence: 99%

Superposition of AC-DBD plasma actuator outputs for three-dimensional disturbance production in shear flows

2023

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This investigation explores the utility of Alternating Current, Dielectric Barrier Discharge (AC-DBD) plasma actuators for producing three-dimensional disturbances of a desired spanwise wavelength via superposition. The technique utilizes two pairs of exposed and covered electrodes on a single dielectric layer arranged in streamwise succession. Two-dimensional forcing is achieved through operation of the upstream, spanwise uniform electrode pair, while three-dimensional forcing at a prescribed spanwise wavelength is attained by operating both electrode pairs simultaneously, with the downstream actuator spanwise modulating the upstream, two-dimensional output. The ability to produce disturbances of different spanwise wavelengths but with equal streamwise wavelength, frequency and total momentum is established through a combined characterization effort that considers quiescent and in-flow conditions. A demonstration of the technique in an exemplary wall-bounded shear flow, a laminar separation bubble, is provided, revealing spanwise wavelength dependent disturbance growth in the flow that could be exploited for performance gains in future flow control endeavours. Graphical abstract

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Parallel vortex body interaction enabled by active flow control

Cited by 8 publications

References 28 publications

Wind Tunnel Experiments on Parallel Blade–Vortex Interaction with Static and Oscillating Airfoil

Wind Tunnel Experiments on Parallel Blade–Vortex Interaction with Static and Oscillating Airfoil

Superposition of AC-DBD plasma actuator outputs for three-dimensional disturbance production in shear flows

Shedding vortex characteristics analysis of NACA 0012 airfoil at low Reynolds numbers

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