Circulation controlled STOL wing optimization

Loth, John L.; Boasson, Michael

doi:10.2514/6.1983-82

Cited by 14 publications

(17 citation statements)

References 9 publications

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“…8 The first person to use the CC concept for high lift generation was Davidson around 1960. 10,11 The most common concept of circulation control applied to fixed wing applications involves ejecting a thin sheet of high momentum jet flow over a curved surface on the trailing edge of the airfoil. This jet flow is usually ejected out of a slot located just upstream of the trailing edge of an airfoil, which is depicted below in Figure 1-2.…”

Section: Circulation Control Backgroundmentioning

confidence: 99%

“…The initial wing/CCW system of the aircraft was redesigned throughout the effort, utilizing a circular trailing edge that folded out (increasing wing area), a drooped leading edge, higher pressure ducting for more uniform slot flow, and boundary layer suction at the hinge of the unfolding trailing edge flap that provided air for the CC blowing. 10,65 The BD-4 aircraft achieved the following design objectives with its CCW: The following CC flight demonstration was performed by the Navy in 1979, flying a CCW retrofitted Grumman A-6. 2,9 The aircraft was equipped with a completely circular non-retractable CC trailing edge, 10,34 slots that were powered by engine bleed air, 66 outboard aerodynamic fences, increased radius leading edge slats that were locked in a 25° deflected position to prevent leading edge stall, 5 a fixed Krueger leading edge flap that was added at the wing glove, wingtip jets to improve adverse yaw tendencies, 67 as well as an inverted leading edge droop added to the horizontal stabilizer to counter the increased downwash.…”

Section: West Virginia University Bd-4mentioning

confidence: 99%

“…10,65 The BD-4 aircraft achieved the following design objectives with its CCW: The following CC flight demonstration was performed by the Navy in 1979, flying a CCW retrofitted Grumman A-6. 2,9 The aircraft was equipped with a completely circular non-retractable CC trailing edge, 10,34 slots that were powered by engine bleed air, 66 outboard aerodynamic fences, increased radius leading edge slats that were locked in a 25° deflected position to prevent leading edge stall, 5 a fixed Krueger leading edge flap that was added at the wing glove, wingtip jets to improve adverse yaw tendencies, 67 as well as an inverted leading edge droop added to the horizontal stabilizer to counter the increased downwash. 47,67 Numerous 2-D and 3-D wind tunnel tests and feasibility studies were conducted, 2,5,46 one of which demonstrated a full 180° of jet turning on a 1/8…”

Section: West Virginia University Bd-4mentioning

confidence: 99%

“…17 The CC flap system employed on the AMELIA design incorporates slots that retract when the system is not in operation to provide decreased cruise drag, which is important for optimizing fuel burn. 10 The CC flaps provide many benefits to the AMELIA design; a less complex flap system, increased lift from over-the-wing engine exhaust entrainment, and a better performing flap that will result in shorter takeoff and landing distances, steeper climb-out and approach angles that reduce community noise, and decreased cruise drag. The use of CC flaps have also shown to be more acoustically acceptable than conventional mechanical flaps, 75 by eliminating the vortex shedding in the trailing edge region of the airfoil.…”

Section: Chapter 2: Problem Statementmentioning

confidence: 99%

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Design and Performance of Circulation Control Geometries

Golden

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DESIGN AND PERFORMANCE OF CIRCULATION CONTROL FLAP GEOMETRIES Rory M. GoldenWith the pursuit of more advanced and environmentally-friendly technologies of today"s society, the airline industry has been pushed further to investigate solutions that will reduce airport noise and congestion, cut down on emissions, and improve the overall performance of aircraft. These items directly influence airport size (runway length), flight patterns in the community surrounding the airport, cruise speed, and many other aircraft design considerations which are setting the requirements for next generation aircraft. Leading the research in this movement is NASA, which has set specific goals for the next generation regional airliners and has categorized the designs that meet the criteria as Cruise Efficient Short Takeoff and Land (CESTOL) aircraft.With circulation control (CC) technology addressing most of the next generation requirements listed above, it has recently been gaining more interest, thus the basis of this research. CC is an active flow control method that uses a thin sheet of high momentum jet flow ejected over a curved trailing edge surface and in turn utilizes Coanda effect to increase the airfoil"s circulation, augmenting lift, drag, and pitching moment. The technology has been around for more than 75 years, but is now gaining more momentum for further development due to its significant payoffs in both performance and system complexity. The goal of this research was to explore the design of the CC flap shape and how it influences the local flow field of the system, in attempt to improve the performance of existing CC flap configurations and provide insight into the aerodynamic characteristics of the geometric parameters that make up the CC flap. Multiple dual radius flaps and alternative flap geometry, prescribed radius, flaps were developed by varying specific flap parameters from a baseline dual radius flap configuration that had been previously v developed and researched. The aerodynamics of the various flap geometries were analyzed at three different flight conditions using two-dimensional CFD. The flight conditions examined include two low airspeed cases with blown flaps at 60° and 90° of deflection, and a transonic cruise case with no blowing and 0° of flap deflection. Results showed that the shorter flaps of both flap configurations augmented greater lift for the low airspeed cases, with the dual radius flaps producing more lift than the corresponding length prescribed radius. The large lift generation of these flaps was accompanied by significant drag and negative pitching moments. The incremental lift per drag and moment produced was best achieved by the longer flap lengths, with the prescribed radius flaps out-performing each corresponding dual radius. Longer flap configurations also upheld the better cruise performance with the least amount of low airspeed flow, drag, and required angle of attack for a given cruise lift coefficient. The prescribed radius flaps also presented a favorable trait of keeping a ...

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Section: Circulation Control Backgroundmentioning

confidence: 99%

Section: West Virginia University Bd-4mentioning

confidence: 99%

Section: West Virginia University Bd-4mentioning

confidence: 99%

Section: Chapter 2: Problem Statementmentioning

confidence: 99%

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Design and Performance of Circulation Control Geometries

Golden

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“…This could possibly be avoided with advances in fly-by-wire technology. Other problems include the extra weight and power consumption associated with the required blowing power for circulation control devices [14].…”

Section: Active Circulation Controlmentioning

confidence: 99%

Comparison of numerical simulation to existing experimental data involving downwash wake reduction for the V-22 Osprey

O'Hara¹

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Pneumatic flow control studies using steady blowing on a supercritical aerofoil

Wong

Kontis

2009

Aeronaut. j.

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Experimental studies have been conducted on a NASA 17-percent thick supercritical aerofoil with a Coanda trailing edge at subsonic speeds in both the boundary-layer control and circulation control regimes. Detailed boundary-layer surveys were performed along the mid span on the suction surface and around the Coanda trailing edge. The wake located at 43% chord-length behind the aerofoil was measured with a single-component hotwire anemometer, and the profile drag coefficients were calculated from the integration of wake momentum deficit. Lift forces and pitching moments were recorded from –20deg to +20deg incidence using a 3-component force balance. In the circulation control regime, the boundary-layer results indicated that separation bubbles are not present at high incidences compared to the boundary-layer control regime, and that minimised the potential for flow separation delay around the Coanda trailing edge. The spectral analysis of the wake showed a significant reduction of wake fluctuations at high incidences and improvement of the stability at the edge of the wake. The study of aerodynamic forces suggested the need to increase the blowing momentum coefficient if the circulation control is used near the stalling angle-of-attack.

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Circulation controlled STOL wing optimization

Cited by 14 publications

References 9 publications

Design and Performance of Circulation Control Geometries

Design and Performance of Circulation Control Geometries

Comparison of numerical simulation to existing experimental data involving downwash wake reduction for the V-22 Osprey

Pneumatic flow control studies using steady blowing on a supercritical aerofoil

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