3D Swept Hybrid Wing Design Method for Icing Wind Tunnel Tests

Abstract

A 3D swept hybrid wing design method using hybrid airfoils is presented for the purpose of icing wind tunnel testing of large commercial aircraft. Hybrid airfoils are those that present the same leading-edge geometry of the full-scale aircraft wing with a redesigned truncated aft section, such that models can fit inside icing wind tunnels and still reproduce full-scale flowfield and ice accretion with reduced chord. The effects of tunnel sidewalls, model sweep angle, aspect ratio, and wind tunnel blockage are presented. Attachment line location is used as a first-order parameter for matching full-scale ice shapes, and methods for controlling its spanwise variation are assessed including the use of gap between model and tunnel wall, aerodynamic twist, and segmented flaps. Finally, model design tradeoffs are presented between competing performance parameters such as full-scale ice accretion agreement, wind tunnel load/speed limits, and model manufacturing/operational complexity. NomenclatureAR = Aspect ratio α = Airfoil angle of attack c fs = Full-scale chord c hyb = Hybrid airfoil chord C p = Pressure coefficient C l = Lift coefficient C m0 = Quarter-chord zero-angle of attack pitching moment coefficient CRM = Common research model CRM65 = 65% scaled common research model δ = Flap deflection, positive down h/c = Tunnel height over model chord η = Wing spanwise position LE = Leading edge RANS = Reynolds-averaged Navier-Stokes equations SF = Scale factor (full-scale chord divided by hybrid chord) s/c = Normalized surface length coordinate

Large-Scale Swept-Wing Icing Simulations in the NASA Glenn Icing Research Tunnel Using LEWICE3D

“…(1.83 m). A more detailed description of this hybrid wing model design is given byWiberg 15 with a more general description of hybrid-wing model design and corresponding trade-offs discussed by the authors 17. …”

A Damage Assessment for Wind Turbine Blades from Heavy Atmospheric Particles

“…[65][66][67] LEWICE was used as a comparison of the water droplet trajectory against two airfoils at two different blade locations. In particular, it was chosen a rain drop diameter d = 2 mm, α = 6 deg, and the blade locations at r/R = 0.70 and 0.90.…”

Computational and Experimental Ice Accretions of Large Swept Wings in the Icing Research Tunnel

“…These scenarios were called the baseline icing conditions and consisted of six aerodynamic cases and seventeen icing conditions. [7][8][9] The aerodynamic solutions of the CRM65 aircraft in free air at flight speed were obtained with the 3D RANS solver OVERFLOW, 10 and then used to generate the ice accretion simulations with LEWICE3D. The set of aerodynamic solutions was called Clean Flight Baseline (CFB), and the set of ice accretion simulations called Iced Flight Baseline (IFB).…”

“…The goal was to identify the minimum number of locations along the wing that could represent the ice accretion along the entire swept wing. 2,4,[7][8][9] Three stations were selected at 20%, 64%, and 83% semispan position of the CRM65, and hybrid wing models were designed for each of these stations applying the method developed by Fujiwara et al 2,4,7 Figure 1 displays the three designed hybrid models inside the IRT test section (6 ft x 9 ft x 20 ft) in comparison to the reference aircraft geometry of the CRM65, illustrating the challenge of full-scale testing a large swept wing model in existing icing wind tunnels. Both oblique and top views are displayed to scale.…”

“…3 Another method relies on designing a wing model with the full-scale leading edge of the wing and a redesigned shortened aft section that produces similar ice accretion characteristics around the leading edge, such that the need for scaling the icing conditions can be reduced or eliminated. This type of model is referred to as a hybrid, 2,4 and was be the kind of model studied in this paper.…”