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Aerodynamic wind tunnel testing of U-beams
Hračov, Stanislav ; Macháček, Michael
The paper presents the outcomes from the experimental testing of the set of slender U-beams in the climatic wind tunnel. All analysed beams have identical basic geometry with the U-shaped cross section given by the side ratio equal to 2 (having the short side perpendicular to the flow), but they differ in the porosity of their flanges and in the depth of their profile. Two depths of the U-profile combined with six different levels of flange porosity are analysed. The U-beams were tested in the smooth flow in order to determine their aerodynamic coefficients for various angles of wind attack. The influences of the depth and porosity onto these coefficients are studied in detail. Moreover, the susceptibility of each individual case to transversal galloping is assessed based on the classical quasi-steady theory. The comparison with the results from the aerodynamic tests of the prisms with rectangular cross-sections having side rations equal to two, four and six is also given and discussed.
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A 2d aerodynamic study on morphing of the naca 2412 aerofoil
Meghani, Pratik
This paper investigates the potential of modifications of the NACA 2412 aerofoil geometry which could be implemented as a morphing wing in the Cessna 172SP. A 2D study on three morphing configurations: landing, take-off and stall maneuvering was conducted. The new geometries were designed using XFLR5. The initial aerodynamics characteristics were computed using XFOIL and compared to that of NACA 2412 in the Cessna 172SP. A selected configuration (landing) was tested at the University of Brighton wind tunnel facility and comparison to XFOIL predictions. Moreover, the ESDU 07010 report was used to extrapolate the Reynold’s number to full scale, which was necessary to obtain an approximation of the aerodynamic characteristics at actual flight. The paper presents results of ANSYS FLUENT simulations for all three configurations. Results reveal that XFOIL is suitable for morphing airfoil configuration analysis but only at low Reynolds number (Re≈500,000). Adaptive aerofoil geometry improves the lift to drag (L/D) ratio by decreasing the drag coefficient; it also expands the flight envelope by delaying stall.
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