Browse Topic: Wings
A study published in Journal of Fluid Mechanics, reveals for the first time how noise is generated and propagated from these engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane’s main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don’t have to work as hard to move the plane, so it burns less fuel
The mystery of how futuristic aircraft embedded engines, featuring an energy-conserving arrangement, make noise has been solved by researchers at the University of Bristol. University of Bristol, Bristol, UK A study published in Journal of Fluid Mechanics, reveals for the first time how noise is generated and propagated from these engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane's main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don't have to work as hard to move the plane, so it burns less fuel. The research, led by Dr. Feroz Ahmed from Bristol's School of Civil, Aerospace and Design Engineering under the supervision of Professor Mahdi Azarpeyvand, utilized the University National Aeroacoustic Wind Tunnel Facility. They were able to identify distinct noise sources originating
Aircraft moving at transonic speeds (i.e., ~0.7 to 0.85 Mach - or near the speed of sound) experience transonic wing flutter. Engineers have traditionally relied on experimental or computational methods to understand wing flutter for the design process. Modeling wing flutter using the customary computational methods requires tens of hours of simulations on a supercomputer that is costly to buy or rent. Having a method to model wing flutter aerodynamics without requiring supercomputer use would (a) increase the efficiency and decrease the cost of aircraft wing design and (b) enable real-time wing-flutter modeling to aid in-flight aircraft operation and control
A research team led by Tao Sun, Associate Professor, University of Virginia, has made new discoveries that can expand additive manufacturing in industries that rely on strong metal parts, including aerospace. The research addresses the issue of detecting the formation of keyhole pores, a major defect in laser powder bed fusion (LPBF), a common additive manufacturing technique introduced in the 1990s
The term “3 inch ice shapes” has assumed numerous definitions throughout the years. At times it has been used to generally characterize large glaze ice accretions on the major aerodynamic surfaces (wing, horizontal stabilizer, vertical stabilizer) for evaluating aerodynamic performance and handling qualities after a prolonged icing encounter. It has also been used as a more direct criterion while determining or enforcing sectional ice shape characteristics such as the maximum pinnacle height. It is the authors’ observation that over the years, the interpretation and application of this term has evolved and is now broadly misunderstood. Compounding the situation is, at present, a seemingly contradictory set of guidance among (and even within) the various international regulatory agencies resulting in an ambiguous set of expectations for design and certification specialists. The focus of this paper is to provide a more complete and accurate historical accounting of “3 inch ice shapes
This paper presents a novel fully-automatic remeshing procedure, based on the level-set method and Delaunay triangulation, to model three-dimensional boundary problems and generate a new conformal body-fitted mesh. The proposed methodology is applied to long-term in-flight ice accretion, which is characterized by the formation of extremely irregular ice shapes. Since ice accretion is coupled with the aerodynamic flow field, a multi-step procedure is implemented. The total icing exposure time is subdivided into smaller time steps, and at each time step a three-dimensional body-fitted mesh, suitable for the computation of the aerodynamic flow field around the updated geometry, is generated automatically. The methodology proposed can effectively deal with front intersections, as shown with a manufactured example. Numerical simulations over a NACA0012 swept wing both in rime and glaze conditions are compared with the experimentally measured ice shapes from the 1st AIAA Ice Prediction
The performance of low-adhesion surfaces in a realistic, in-flight icing environment with supercooled liquid droplets is evaluated using a NACA 0018 airfoil in the National Research Council of Canada Altitude Icing Wind Tunnel. This project was completed in collaboration with McGill University, the University of Toronto and the NRC Aerospace Manufacturing Technologies Centre in March 2022. Each collaborator used significantly different methods to produce low-adhesion surface treatments. The goal of the research program was to demonstrate if the low-adhesion surfaces reduced the energy required to de-ice or anti-ice an airfoil in an in-flight icing environment. Each collaborator had been developing their own low-adhesion surfaces, using bench tests in cold rooms and a spin rig in the wind tunnel to evaluate their performance. The most promising surface treatments were selected for testing on the airfoil. The de-icing and anti-icing performance of the low-adhesion surfaces was compared
Even going as far back as bird-like dinosaurs, ornithological animals have always benefited from folding their wings during upstroke. This makes birds an interesting inspiration for the development of drones. However, determining which flapping strategy is best requires aerodynamic studies. So, a Swedish-Swiss research team has constructed a robotic wing that can flap like a bird
NASA Washington, D.C
Hummingbirds fly like insects but have the musculoskeletal system of birds. According to Bo Cheng, the Kenneth K. and Olivia J. Kuo Early Career Associate Professor in Mechanical Engineering at Penn State, hummingbirds have extreme aerial agility and flight forms, which is why many drones and other aerial vehicles are designed to mimic hummingbird movement. Using a novel modeling method, Cheng and his team of researchers gained new insights into how hummingbirds produce wing movement, which could lead to design improvements in flying robots
This study consists of a novel approach based on Classical Mechanics to explain the aerodynamic forces on a body in motion relating to a fluid. This new approach does not require the presence of viscosity to generate the forces and is compatible with the Kutta condition. The physical reasoning of the approach is outlined with the introduction of the aerodynamic suction effect of the body. Next, the mathematical expressions and a code that models the physical phenomena are developed. These are applied for the case of a sphere immersed in a moving fluid and then an airfoil. An initial validation of this new approach is performed by a comparison of the theoretical results and the available results of the National Advisory Committee for Aeronautics (NACA) airfoils. This new mathematical approach is especially valid for high Reynolds numbers where viscosity can be neglected. The new codes based on this approach is less complex than other computational fluid dynamics (CFD) approaches based
This SAE Aerospace Recommend Practice (ARP) is intended to cover the external lights on fixed wing aircraft for illuminating the wing leading edge and engine nacelles and the upper surfaces of the wing. The addition of an ice detection system should be implemented when the areas to inspect are not visible from the aircraft cockpit. It is not intended that this recommended practice require the use of any particular light source such as halogen, LED, or other specific design of lamp
At hypersonic speed, severe aerodynamic heating is observed, and temperatures are too high to cool by radiation cooling; active cooling such as ablative cooling is helpful in this situation. The Thermal Protection System (TPS) consists of a layer of an ablative material, followed by an insulating material to lower the temperature at the inside wall of the lifting body. The surface area (considering the inside volume of the vehicle constant) of the TPS plays a vital role in heat transfer to the vehicle and heat transferred through the vehicle body. The minimum area sweepback angle (ΛArea-min) is the function of the principal radius (R) and the ratio of the principal radii of the forward bi-curvature stagnation surface (R/r). The ΛArea-min = 80° is obtained for R = 2 m and R/r = 2. The aerothermal analysis of the lifting body is of fundamental interest while designing the TPS. A Computational Fluid Dynamics (CFD) simulation of a two-dimensional (2D) lifting body against thermally perfect
Conventional high-lift systems allow transport aircraft to safely operate at low speeds for landing and takeoff. These high-lift devices, such as Fowler flaps, are complex, heavy, and have high part counts. Fowler flap mechanisms also protrude externally under the wings, requiring external fairings, which increase cruise drag. Simple-hinged flaps are less complex, and an ideal choice for low-drag cruise efficiency. However, simple-hinged flaps require high flap deflections to achieve lift comparable to Fowler flaps. These flap deflections cause severe adverse pressure gradients, which generate flow separation that is difficult to control. In response to these challenges, NASA developed the High Efficiency Low Power (HELP) active flow control (AFC) system
Fireflies have sparked the inspiration of MIT researchers. Taking a cue from nature, they built electroluminescent soft artificial muscles for flying, insect-scale robots. The tiny artificial muscles that control the robots’ wings emit colored light during flight
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