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Airfoil

About: Airfoil is a research topic. Over the lifetime, 24696 publications have been published within this topic receiving 337709 citations. The topic is also known as: aerofoil & wing section.


Papers
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Proceedings ArticleDOI
13 Jun 2011
TL;DR: In this article, a single wedge-type airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests at Mach numbers of 0.2 to 0.3, total pressures from 93 to 45 kPa, and total temperatures from 5 to 15 C. The ice appeared well adhered to the surface in the lowest pressure tests (45 kPa) and, in particular, showed continuous leading-edge ice growth to a thickness greater than 15 millimeters in 3 minutes.
Abstract: Due to numerous engine power-loss events associated with high-altitude convective weather, ice accretion within an engine due to ice-crystal ingestion is being investigated. The National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada are starting to examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions. In November 2010, two weeks of testing occurred at the NRC Research Altitude Facility utilizing a single wedge-type airfoil designed to facilitate fundamental studies while retaining critical features of a compressor stator blade or guide vane. The airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests. Aerodynamic testing showed excellent agreement compared with CFD data on the icing pressure surface and allowed calculation of heat transfer coefficients at various airfoil locations. Icing tests were performed at Mach numbers of 0.2 to 0.3, total pressures from 93 to 45 kPa, and total temperatures from 5 to 15 C. Ice and liquid water contents ranged up to 20 and 3 grams per cubic meter, respectively. The ice appeared well adhered to the surface in the lowest pressure tests (45 kPa) and, in a particular case, showed continuous leading-edge ice growth to a thickness greater than 15 millimeters in 3 minutes. Such widespread deposits were not observed in the highest pressure tests, where the accretions were limited to a small area around the leading edge. The suction surface was typically ice-free in the tests at high pressure, but not at low pressure. The icing behavior at high and low pressure appeared to be correlated with the wet-bulb temperature, which was estimated to be above 0 C in tests at 93 kPa and below 0 C in tests at lower pressure, the latter enhanced by more evaporative cooling of water. The authors believe that the large ice accretions observed in the low pressure tests would undoubtedly cause the aerodynamic performance of a compressor component such as a stator blade to degrade significantly, and could damage downstream components if shed.

77 citations

Proceedings ArticleDOI
12 Jan 1984
TL;DR: In this article, experimental measurements of the ice shapes and resulting drag increases were measured in the NASA-Lewis Icing Research Tunnel, and additional results were given which are helpful in understanding the ice structure and the way it forms, and in improving the ice accretion modeling theories.
Abstract: Experimental measurements of the ice shapes and resulting drag increases were measured in the NASA-Lewis Icing Research Tunnel. The measurements were made over a large range of conditions (e.g., airspeed and temperature, drop size and liquid water content of the cloud, and the angle of attack of the airfoil). The measured drag increase did not agree with the existing correlation. Additional results were given which are helpful in understanding the ice structure and the way it forms, and in improving the ice accretion modeling theories. There are data on the ice surface roughness, on the effect of the ice shape on the local droplet catch, and on the relative importance of various parts of the ice shape on the drag increase. Experimental repeatability is also discussed.

76 citations

Journal ArticleDOI
TL;DR: In this article, the influence of mounting angles and mounting locations on the lift-enhancing effects of Gurney flaps at a Reynolds number of 2.1 x 10 6 was investigated.
Abstract: Experimental investigations were conducted on a NACA0012 airfoil to determine the influences of mounting angles and mounting locations on the lift-enhancing effects of Gurney flaps at a Reynolds number of 2.1 x 10 6 . The results revealed that all flaps of different mounting angles increased the lift coefficient, and an increment of maximum lift coefficient of 12.3, 15.1, and 17.4% was obtained by 45-, 60-, and 90-deg Gurney flap, respectively. There was a drag penalty associated with the lift enhancement. The best performance was obtained by the 45-deg Gurney flap for all flap deflections tested. When shifted forward from the trailing edge of the airfoil, the Gurney flap led to a decrease in lift, and an increment in drag, and thus a reduction in lift-to-drag ratio

76 citations

Journal ArticleDOI
TL;DR: In this article, the simulation of an inverted cambered aerofoil in ground effect was studied numerically by solving the Reynolds-averaged Navier-Stokes equations.
Abstract: The pressure and wake of an inverted cambered aerofoil in ground effect was studied numerically by solving the Reynolds-averaged Navier-Stokes equations. Efforts were focused on the setting up of an accurate numerical model and assessing the abilities of various turbulence models in capturing major physical features associated with the flow, such as surface pressure distribution, separation, level of downforce, and wake. A number of ride heights were studied covering various force regions. Surface pressures, sectional forces, and wake characteristics were compared to experimental data. The k–? SST and Realizable k–? turbulence models were found to offer good overall simulations, with the k–? SST performing better for the surface pressure and the Realizable k–? better for the wake. The simulations at various ride heights correctly captured the trends in flow-field variations with ride height. The surface pressures, wake flow field, and region of separation on the suction surface of the aerofoil, at lower ride heights, were all modeled accurately.

76 citations

Journal ArticleDOI
TL;DR: In this article, a type of piezoceramic composite actuator known as Macro-Fiber Composite (MFC) is used for changing the camber of the wings.
Abstract: The purpose of the research presented here is to exploit actuation via smart materials to perform shape control of an aerofoil on a small aircraft and to determine the feasibility and advantages of smooth control surface deformations. A type of piezoceramic composite actuator known as Macro-Fiber Composite (MFC) is used for changing the camber of the wings. The MFC actuators were implemented on a 30° swept wing, 0·76m wingspan aircraft. The experimental vehicle was flown using two MFC patches in an elevator/aileron (elevon) configuration. Preliminary flight and wind-tunnel testing has demonstrated the stability and control of the concept. Flight tests were performed to quantify roll control using the MFC actuators. Lift and drag coefficients along with pitch and roll moment coefficients were measured in a low-speed, open-section wind tunnel. A vortex-lattice analysis complemented the database of aerodynamic derivatives used to analyse control response. The research, for the first time, successfully demonstrated that piezoceramic devices requiring high voltages can be effectively employed in small air vehicles without compromising the weight of the overall system.

76 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,083
20221,871
2021923
2020979
20191,097
20181,002