Influence of Finite Span and Sweep on Active Flow Control Efficacy

Greenblatt, David; Washburn, Anthony E.

doi:10.2514/1.33809

Cited by 62 publications

(6 citation statements)

References 26 publications

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“…We verified that the streamwise C p measurements (not shown) with the new upper spar and aft SLA actuator sections agreed with those acquired in previous studies. 14,15 In general, there was good agreement between the two data sets, with the largest di↵erence being at the y/s=0.99 location. These di↵erences may be due to the larger step noticed between the outboard edge of the model and the endcap of the model.…”

Section: Afc Resultsmentioning

confidence: 78%

“…The model tested is an unswept semi-span wing with a chord of 0.305 meters, a span of 0.610 meters, and a NACA 0015 airfoil cross-section that was built for sidewall AFC testing in the BART facility. [14][15][16] Figure 1(a) shows a sketch of the model installation. The wing, shown in Fig.…”

Section: B Model Descriptionmentioning

confidence: 99%

“…Previously, zero-net mass flux actuators were shown to be unable to produce any meaningful improvement in lift on the swept configuration. 14 While the SWJ actuators investigated were able to control separation on the swept configuration, the momentum required was high. The results presented in this paper are part of an e↵ort to reduce the momentum required for e↵ective control of separation when using this sweeping jet actuator geometry.…”

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confidence: 99%

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Active Flow Control Using Sweeping Jet Actuators on a Semi-Span Wing Model

Melton

Köklü

2016

54th AIAA Aerospace Sciences Meeting

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Wind tunnel experiments were performed using active flow control on an unswept semispan wing model with a 30% chord trailing edge flap to aid in the selection of actuators for a planned high Reynolds number experiment. Two sweeping jet actuator sizes were investigated to determine the influence of actuator size on the active flow control system e ciency. Sweeping jet actuators with orifice sizes of 1 mm x 2 mm and 2 mm x 4 mm were selected because of the di↵erences in actuator jet sweep angle. The parameters that were varied include actuator momentum, freestream velocity, and trailing edge flap deflection angle. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the two actuators. In addition to the wind tunnel experiments, benchtop studies of the actuators were performed to characterize the jets produced by each actuator. Benchtop investigations of the smaller actuator reveal that the jet exiting the actuator has a reduced sweep angle compared to published data for larger versions of this type of actuator. The larger actuator produces an oscillating jet that attaches to the external di↵user walls at low supply pressures and produces the expected sweep angles. The AFC results using the smaller actuators show that while the actuators can control flow separation, the selected spacing of 3.3 cm may be too large due to the reduced sweep angle. In comparison, the spacing for the larger actuators, 6.6 cm, appears to be optimal for the Mach numbers investigated. Particle Image Velocimetry results are presented and show how the wall jets produced by the actuators cause the flow to attach to the flap surface.

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Section: Afc Resultsmentioning

confidence: 78%

Section: B Model Descriptionmentioning

confidence: 99%

mentioning

confidence: 99%

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Active Flow Control Using Sweeping Jet Actuators on a Semi-Span Wing Model

Melton

Köklü

2016

54th AIAA Aerospace Sciences Meeting

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“…The model tested is a 0.305 m chord (c), 0.610 m semipan (s) wing with a NACA 0015 cross-section that was built for sidewall-mounted AFC testing in the BART facility. 21,22,23 The wing is unswept and has a 30% chord trailing edge flap that can be tested at flap deflection angles, f , from -10 to 40 in 10 increments. The 0.61 m span flap is split into three equal-span components that can be deflected independently.…”

Section: Introductionmentioning

confidence: 99%

Sweeping Jet Optimization Studies

Melton

Köklü

Andino

et al. 2016

8th AIAA Flow Control Conference

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Progress on experimental e↵orts to optimize sweeping jet actuators for active flow control (AFC) applications with large adverse pressure gradients is reported. Three sweeping jet actuator configurations, with the same orifice size but di↵erent internal geometries, were installed on the flap shoulder of an unswept, NACA 0015 semi-span wing to investigate how the output produced by a sweeping jet interacts with the separated flow and the mechanisms by which the flow separation is controlled. For this experiment, the flow separation was generated by deflecting the wing's 30% chord trailing edge flap to produce an adverse pressure gradient. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the three actuator configurations. The actuator with the largest jet deflection angle, at the pressure ratios investigated, was the most e cient at controlling flow separation on the flap of the model. Oil flow visualization studies revealed that the flow field controlled by the sweeping jets was more three-dimensional than expected. The results presented also show that the actuator spacing was appropriate for the pressure ratios examined.

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“…where Δx TE is the distance from the throat to the trailing edge of the flap and λ is the wavelength of the sweeping jet. Previous synthetic jet studies 22 characterized f + to improve lift performance for a high-lift configurations. Typical lift coefficient improvements for those studies occurred for an f + range of 0.5 to 4.0.…”

Section: Introductionmentioning

confidence: 99%