A Wind Tunnel Model to Explore Unsteady Circulation Control for General Aviation Applications

Cagle, Christopher M.; Jones, Gregory S.

doi:10.2514/6.2002-3240

Cited by 27 publications

(16 citation statements)

References 1 publication

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“…The airfoil for the circulation control wing is based on the Georgia Tech Research Institute's Dual Radius Circulation Control airfoil 14 . This airfoil was chosen because out of all of the airfoil shapes that have been tested the dual radius is the only mechanically simple system that allows for both low cruise drag and a large Coanda flap surface for high lift during takeoff and landing.…”

Section: A Two-dimensional Airfoilmentioning

confidence: 99%

Circulation Control and Its Application to Extreme Short Take-Off and Landing Vehicles

Montanya

Marshall

2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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Circulation Control is a high-lift method discovered in 1935 when Henry Coanda accidentally stumbled upon the technology. Research was conducted in the 1970's and 1980's to develop this technique, but the idea fell out of vogue until recently. Energy is introduced into the flow field by means of a jet ejected tangentially from a slot located near the trailing edge of the airfoil; thus changing the effective chamber of the airfoil and increasing lift. Extreme Short Take-Off and Landing (ESTOL) vehicles can use this technology to alleviate today's congested airports by reutilizing the small runways that are currently unexploited due to the recent trend of bigger aircraft. By examining the angle-of-attack, flap deflection angle, and jet blowing coefficient, a design space was analyzed for lift and drag revealing three-dimensional lift coefficients up to 3.5. After collecting the data, balanced field length and landing distances were calculated. These results revealed that the shortest balanced field length of 2,400 feet would be for a flap deflection angle of thirty degrees and a blowing coefficient equal to 0.35. Similarly, the shortest landing distance was calculated to be 2,000 feet for a flap deflection angle of ninety degrees and a blowing coefficient of 0.34. Both of these values fall within the NASA defined mission requirements 46 for an ESTOL aircraft to have a balanced field length and landing distance between 2,000 to 3,000 feet, proving Circulation Control to be an extremely viable resource for ESTOL technology.

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Section: A Two-dimensional Airfoilmentioning

confidence: 99%

Circulation Control and Its Application to Extreme Short Take-Off and Landing Vehicles

Montanya

Marshall

2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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“…Figure 2 shows the sketch map of the trailing edge Coanda surface design. The procedure is given as follows: (1) Copy the upper and lower surface profile lines, and translate them inward by a distance of 0.5% chord, forming lines m and n; (2) Construct a circle with the constraint that the circle is tangent to the upper and lower translated lines m and n, as well as the trailing edge line, forming three tangency points E, F and P; (3) Connect the center point O of the circle to the two tangency points E and F, respectively, and then extend the two line segments OE and OF to intersect with the upper and lower profile lines, obtaining two intersection points C Energies 2018, 11, 619 4 of 26 and D; (4) For traditional circulation control, the whole part of the circular surface EPF is treated as the Coanda surface [21,[25][26][27], as shown in Figure 2b. This traditional CC approach is denoted as full circulation control (FCC) in the present study, in order to distinguish it from the newly proposed partial circulation control (PCC) shown in Figure 2c.…”

Section: Description Of CC Airfoil Configurationsmentioning

confidence: 99%

Flow Control over the Blunt Trailing Edge of Wind Turbine Airfoils Using Circulation Control

Dong

Qiao

et al. 2018

Energies

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Abstract:A new partial circulation control (PCC) method is implemented on the blunt trailing edge DU97-Flatback airfoil, and compared with the traditional full circulation control (FCC) based on numerical analysis. When the Coanda jet is deactivated, PCC has an attractive advantage over FCC, since the design of PCC doesn't degrade aerodynamic characteristics of the baseline flatback section, in contrast to FCC, which is important in practical use in case of failure of the circulation control system. When the Coanda jet is activated, PCC also outperforms FCC in several respects. PCC can produce much higher lift coefficients than FCC over the entire range of angles of attack as well as the entire range of jet momentum coefficients under investigation, but with slightly higher drag coefficients. The flow field of PCC is less complex than that of FCC, indicating less energy dissipation in the main flow and hence less power expenditure for the Coanda jet. The aerodynamic figure of merit (AFM) and control efficiency for circulation control are defined, and results show that PCC has much higher AFM and control efficiency than FCC. It is demonstrated that PCC outperforms FCC in terms of effectiveness, efficiency and reliability for flow control in the blunt trailing edge wind turbine application.

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“…A wide range of applications would benefit when it comes to delaying or advancing to boundary layer transition, triggering or ceasing turbulence and delaying or initiating separation [15]. The active flow control studies primarily focus on the aerodynamics and aeroacoustic improvements by steady flow suction and blowing on airfoils [17][18][19] and the circulation control, the coanda effect [16][17][18][19].…”

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confidence: 99%

Airfoil Trailing-edge Noise Reduction using Flow Suction

Cesar¹,

Jawahar²,

Azarpeyvand³

2018

2018 AIAA/CEAS Aeroacoustics Conference

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Large eddy simulations were carried out for a NACA-0012 airfoil with trailing edge flow suction at the angle of attack α = 0• for a chord-based Reynolds number of Re c = 4 × 10 5 . Simulations were performed with different flow suction rates to demonstrate the viability of the technique. The baseline case was thoroughly validated with experimental data. The aerodynamic and aeroacoustic characteristics of the boundary layer and wake were studied in detail for different flow suction rates. The mean velocity results showed reduced wake velocity deficit. Results have also shown that the suction of the boundary flow upstream of the trailing edge can reduce the boundary layer and wake turbulent kinetic energy and significant reduction of the wall pressure spectra near the trailing edge. The effect of flow suction on the spanwise correlation length has also been studied. The results have shown that a moderate flow suction rate can result in partial flow laminarization, broadband reduction of the surface pressure spectra and the radiated noise from the trailing edge.

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A Wind Tunnel Model to Explore Unsteady Circulation Control for General Aviation Applications

Cited by 27 publications

References 1 publication

Circulation Control and Its Application to Extreme Short Take-Off and Landing Vehicles

Circulation Control and Its Application to Extreme Short Take-Off and Landing Vehicles

Flow Control over the Blunt Trailing Edge of Wind Turbine Airfoils Using Circulation Control

Airfoil Trailing-edge Noise Reduction using Flow Suction

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