Experimental Study of Flow Separation over NACA63<sub>3</sub>018 Wing with Synthetic Jet Control at Low Reynolds Numbers

Lin, Chi-Yu; Hsiao, Fei‐Bin

doi:10.1017/jmech.2012.120

Cited by 6 publications

(4 citation statements)

References 12 publications

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“…In this case, the jets interact with the surrounding flow field by eliminating, or simply reducing, the upper surface separation bubble with consequent lift-drag ratio improvement. Moreover, further studies pointed out the detrimental effect of the Reynolds number on the SJAs performance [16]. All of the cited phenomena have been confirmed and are in agreement with the major outcomes of the presented experimental investigation.…”

Section: Introductionsupporting

confidence: 88%

“…Cases of SJAs application on non-symmetric-airfoil-wing are also available in literature. A case in point is [16], where a series of piezo-electric driven SJAs, located at the 12% of the chord on a wing, is employed to control the airflow around a NACA633018 airfoil, at low Reynolds number conditions. In this case, the jets interact with the surrounding flow field by eliminating, or simply reducing, the upper surface separation bubble with consequent lift-drag ratio improvement.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation on a 3D Wing Section Hosting Multiple SJAs for Stall Control Purpose

Andreoli

Cassaro

Battipede

et al. 2015

SAE Technical Paper Series

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The control of the flow over aerodynamic shapes in order to achieve performance enhancements, such as improved aircraft maneuverability, has been a lively area of research for last two decades. Active flow control can produce significant performance improvement when combined in a closed-loop control system. Synthetic jet actuators (SJAs) are devices able to interact actively with the flow around a hosting structure by providing ejection and suction of fluid from an orifice. The research presented in this paper concerns the implementation of zero-net-mass-flux SJAs airflow control system on a NACA0015, low aspect ratio (LAR) wing section prototype developed by Clarkson University under the Advancement of Intelligent Aerospace Systems (AIAS) AFOSR Grant FA9550-09-1-0051. Two arrays of custom made SJAs, installed in the proximity of the leading edge and flap of the wing section, make up the actuation system. The sensing system consists of eleven acoustic pressure transducers distributed in the wing upper surface, an accelerometer placed in proximity of the wing center of gravity and a six-axis force balance. A dSPACE hardware connected to the software environment Matlab / Simulink / Control Desk complete the test architecture. Wind tunnel experiments, on the uncontrolled wing, are primarily performed for system identification purpose. The open-loop control of the wing is implemented and tested, obtaining a stall postposition of about 2.8 degrees of angle of attack. A strategy based on the comparison of the mean pressure chord-wise distributions, senses by the acoustic pressure transducers for different angles of attack, on the wing upper surface is adopted to characterize the forthcoming boundary layer detachment. This allows for triggering the closed-loop control in stall proximity only for energy saving purpose. Pertinent results and discussion are provided.

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Section: Introductionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on a 3D Wing Section Hosting Multiple SJAs for Stall Control Purpose

Andreoli

Cassaro

Battipede

et al. 2015

SAE Technical Paper Series

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“…Synthetic jet actuators (SJAs) presented here belong to the classification of active-control devices. These devices have been applied in numerous fields, such as aircraft performance (Seifert et al , 1998; Glezer et al , 2005; Duvigneau and Visonneau, 2006; Ciuryla et al , 2007; Amir and Kontis, 2008; Farnsworth et al , 2008; Lin and Hsiao, 2013), electronics cooling (Mahalingam and Glezer, 2005; Pavlova and Amitay, 2006; Jang and Lee, 2014), fluid mixing (Xia and Zhong, 2013, 2014; Davis and Glezer, 1999), thermal management, and heat transfer (Akdag et al , 2013; Fanning et al , 2015; Iwana et al , 2015; Liu et al , 2015; Tan et al , 2015). More recently, the parameters used to optimize the control of SJAs have also attracted much attention.…”

Section: Introductionmentioning

confidence: 99%

Flow characteristics of two-dimensional synthetic jets under diaphragm resonance excitation

Lin¹

2019

AEAT

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Purpose This paper aims to experimentally study the external flow characteristic of an isolated two-dimensional synthetic jet actuator undergoing diaphragm resonance. Design/methodology/approach The resonance frequency of the diaphragm (40 Hz) depends on the excitation mechanism in the actuator, whereas it is independent of cavity geometry, excitation waveform and excitation voltage. The velocity response of the synthetic jet is influenced by excitation voltage rather than excitation waveform. Thus, this investigation selected four different voltages (5, 10, 15 and 20 V) under the same sine waveform as experiment parameters. Findings The velocity field along the downstream direction is classified into five regions, which can be obtained by hot-wire measurement. The first region refers to an area in which flow moves from within the cavity to the exit of orifice through the oscillation of the diaphragm, but prior to the formation of the vortex of a synthetic jet. In this region, two characteristic frequencies exist at 20 and 40 Hz in the flow field. The second region refers to the area in which the vortices of a synthetic jet fully develop following their initial formation. In this region, the characteristic frequencies at 20 and 40 Hz still occur in the flow field. The third region refers to the area in which both fully developed vortices continue traveling downstream. It is difficult to obtain the characteristic frequency in this flow field, because the mean center velocities (ū) decay downstream and are proportional to (x/w)−1/2 for the four excitation voltages. The fourth region reveals variations in both vortices as they merge into a single vortex. The mean center velocities (ū) are approximately proportional to (x/w)0 in this region for the four excitation voltages. A fifth region deals with variations in the vortex of a synthetic jet after both vortices merge into one, in which the mean center velocities (ū) are approximately proportional to (x/w)−1 in this region for the four excitation voltages (x/w is the dimensionless streamwise distance). Originality/value Although the flow characteristics of synthetic jets had reported for flow control in some literatures, variations of flow structure for synthetic jets are still not studied under the excitation of diaphragm resonance. This paper showed some novel results that our velocity response results obtained by hot-wire measurement along the downstream direction compared with flow visualization resulted in the classification of five regions under the excitation of diaphragm resonance. In the future, it makes valuable contributions for experimental findings to provide researchers with further development of flow control.

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“…One of important property of synthetic jet is a zero-net-mass-flux jet whereas it is a nonzero-momentum-flux jet [3,7,8]. Many researchers have investigated the application of SJAs in the cooling of electronics [9,10], fluid mixing [11] and flow control [12][13][14][15]. These researchers were also interested in determining the optimal operating parameters for flow control using SJAs.…”

Section: Introductionmentioning

confidence: 99%

Analysis of external flow characteristics in two-dimensional synthetic jets under excitation produced by cavity resonance

Lin¹,

Lin²,

Yang³

2016

J. vibroeng.

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The paper studies the behaviors of synthetic jets under the excitation of cavity resonance which is produced by an isolated two-dimensional actuator. A cross hot-wire was used to obtain measurements within the velocity field. This research revealed a number of notable phenomena, such as the appearance of vortex pairs only in the vicinity of orifice exit as well as their rapid dissipation downstream. Our results of analysis of the plane velocities of the synthetic jets indicate that effective flow control can be achieved only in regions close to the orifice. It is interesting to note that a linear relationship could be obtained only by taking the logarithm of mean velocity () as well as downstream distance () in different transverses, and by using a curve fitting then linear relations can be obtained. The slopes of synthetic jets under excitation of cavity resonance were between-7/10 and-3/5, which represents a sine wave of 160 Hz on 15 V. The original time-domain data was then converted using fast Fourier transform to the show power spectrum in order to reveal more about the flow behavior of synthetic jets. Characteristic frequencies were identified at 80 Hz and 160 Hz in the initial center of the orifice. The former frequency (80 Hz) can be attributed to the collision of the upper vortex and lower vortex of the synthetic jet. The latter frequency (160 Hz) refers to the excitation frequency of the signal source. Following the development of the synthetic jet, the excitation frequency of 160 Hz eventually disappeared downstream but the characteristic frequency of 80 Hz remained until / = 8. These experimental results make a valuable contribution to the further development of flow control in the future.

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Experimental Study of Flow Separation over NACA63₃018 Wing with Synthetic Jet Control at Low Reynolds Numbers

Cited by 6 publications

References 12 publications

Experimental Investigation on a 3D Wing Section Hosting Multiple SJAs for Stall Control Purpose

Experimental Investigation on a 3D Wing Section Hosting Multiple SJAs for Stall Control Purpose

Flow characteristics of two-dimensional synthetic jets under diaphragm resonance excitation

Analysis of external flow characteristics in two-dimensional synthetic jets under excitation produced by cavity resonance

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Experimental Study of Flow Separation over NACA633018 Wing with Synthetic Jet Control at Low Reynolds Numbers

Cited by 6 publications

References 12 publications

Experimental Investigation on a 3D Wing Section Hosting Multiple SJAs for Stall Control Purpose

Experimental Investigation on a 3D Wing Section Hosting Multiple SJAs for Stall Control Purpose

Flow characteristics of two-dimensional synthetic jets under diaphragm resonance excitation

Analysis of external flow characteristics in two-dimensional synthetic jets under excitation produced by cavity resonance

Contact Info

Product

Resources

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Experimental Study of Flow Separation over NACA63₃018 Wing with Synthetic Jet Control at Low Reynolds Numbers