Numerical Investigation of Active Flow Control Applied to an Airfoil with a Camber Flap

Günther, Bert; Carnarius, Angelo; Thiele, Frank

doi:10.1007/978-3-642-11735-0_4

Cited by 8 publications

(2 citation statements)

References 11 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The width of the slot was designed to be 0.1% of the chord length of the airfoil based on the recommendations of Englar,18 who performed a parametric study on slot sizing involving the jet kinetic energy, coanda effect and power requirement for actuation. The exit of the blowing slot was inclined at an angle of 30 o with respect to the local tangent at the surface to enhance the effectiveness of pulsed actuation (Gunther et al 19 ). The path of the blowing slot was designed with a circular cross-section on the inlet side which transformed seamlessly into a rectangular profile at the exit, as shown in Fig.…”

Section: Airfoil Model and Flow Control Systemmentioning

confidence: 99%

Open-Loop and Closed-Loop Trailing-Edge Separation Control on a Natural Laminar Flow Airfoil

Gupta

Ansell

2016

54th AIAA Aerospace Sciences Meeting

View full text Add to dashboard Buy / Rent full text

Active Unsteady Flow Control experiments were performed on a Natural Laminar Flow, NLF 0414 airfoil at Rec = 1.0 × 10 6 in a 3-ft × 4-ft low-speed, low-turbulence wind tunnel. The NLF 0414 was designed with a region of favorable pressure gradient extending almost 70% of the chord on the upper surface of the airfoil. Aggressive pressure recovery in the aft 30% of the chord near the trailing edge results in the separation of the flow from the airfoil surface at the off-design conditions. The goal of this study was to control boundary-layer separation across the trailing-edge region of the airfoil in an effort to improve the performance beyond the designed angle-of-attack range. Active control of separation was achieved using a series of fast-switching solenoid valves connected to blowing slots at x/c = 0.75 on the upper surface of the airfoil. The airfoil in its baseline configuration was first evaluated to identify the dominant modes in the spectral content of unsteady Cp. Airfoil performance data were then acquired across a parametric range of blowing amplitudes, actuation frequencies and duty cycles in order to understand the effects of variations in the major forcing parameters on the performance of the model. Phase-averaged and phase-locked planar PIV measurements were also acquired across a horizontal plane near the trailing-edge region of the airfoil model in order to examine the spatio-temporal evolution of the flowfield and understand the mechanism responsible for the alleviation of separation as a result of actuation at the different flow control settings. A closed loop controller was developed to vary the actuation parameters in-situ using sensory feedback from the unsteady surface pressure measurements. Adaptive modal decomposition methods were used to identify the frequencies of natural instabilities in the flowfield in real-time. A proportional controller was designed to automatically control the blowing amplitude by estimating the state of the flow and the extent of boundary-layer separation. The closed-loop system was able to simultaneously control the blowing amplitude and the actuation frequency such that a desired value of Cl was obtained.

show abstract

Section: Airfoil Model and Flow Control Systemmentioning

confidence: 99%

Open-Loop and Closed-Loop Trailing-Edge Separation Control on a Natural Laminar Flow Airfoil

Gupta

Ansell

2016

54th AIAA Aerospace Sciences Meeting

View full text Add to dashboard Buy / Rent full text

show abstract

“…The performance of the aircraft wing is seriously damaged if flow separation occurs [3]. Nowadays, modern airplanes use complex multi-element high-lift devices consisting of the slat and single or multiple flaps in order to generate the high lift required during takeoff and landing for reducing runway lengths and ground speeds [4]. Multi-element wing designs, however, are found unfavorable from a weight and complexity point of view, and they increase the wing efficiency.…”

Section: Introductionmentioning

confidence: 99%

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Fatahian

Nichkoohi

Salarian

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

View full text Add to dashboard Buy / Rent full text

In the present study, the effect of hinge position (H) has been numerically investigated to find the appropriate position for improving the aerodynamic performance of the NACA 0012 flapped airfoil. In addition, perpendicular and tangential suctions have been applied to control the flow separation and enhance the aerodynamic performance over the NACA 0012 flapped airfoil at each different hinge positions. The simulations were carried out at a Reynolds number of 5 × 10 5 (Ma = 0.021) based on two-dimensional incompressible unsteady Reynolds-averaged Navier-Stokes calculations to determine the adequate hinge position. The turbulence was modeled using the shear stress transport k-ω turbulence model. The effect of perpendicular suction (θ jet = − 90°) and tangential suction (θ jet = − 30°) was computationally studied over NACA 0012 flapped airfoil for five different hinge positions (H = 0.7c, 0.75c, 0.8c, 0.85c and 0.9c) and a flap deflection (δ f) of 15°. Based on the results, the hinge position significantly affects the aerodynamic performance of the airfoil. The lift coefficient increased clearly as the hinge position moved to the trailing edge of the airfoil. Using perpendicular suction caused to increase the lift coefficient and decrease the drag coefficient. Consequently, the maximum value of the lift-to-drag ratio (C L /C D) for perpendicular and tangential suctions was achieved about 35.8% and 25.1% higher than that of the case without suction at an angle of attack of 12° and H = 0.9c. Also, the effect of perpendicular suction was more considerable compared to the tangential suction. This caused a reduction in the size of the recirculation zone from 0.5 to 0.09 of the airfoil chord length and also transferred it from 1.13 to 1.18 of the airfoil chord length.

show abstract

Numerical Investigation of Active Flow Control Applied to an Airfoil with a Camber Flap

Cited by 8 publications

References 11 publications

Open-Loop and Closed-Loop Trailing-Edge Separation Control on a Natural Laminar Flow Airfoil

Open-Loop and Closed-Loop Trailing-Edge Separation Control on a Natural Laminar Flow Airfoil

Effects of the hinge position and suction on flow separation and aerodynamic performance of the NACA 0012 airfoil

Contact Info

Product

Resources

About