Aerodynamic Shape Optimization of an Adaptive Morphing Trailing Edge Wing
Z. Lyu, and J. R. R. A. Martins
Journal of Aircraft, 52(6):1951–1970, 2015
Adaptive morphing trailing edge wings have the potential to reduce the fuel burn of transport aircraft. However, to take full advantage of this technology and to quantify its benefits, design studies are required. To address this need, we quantify the aerodynamic performance benefits of a morphing trailing edge wing using aerodynamic design optimization. The aerodynamic model solves the Reynolds-averaged Navier–Stokes equations with a Spalart–Allmaras turbulence model. A gradient-based optimization algorithm is used in conjunction with an adjoint method that computes the required derivatives. The baseline geometry is optimized using a multipoint formulation and 192 shape design variables. The average drag coefficient is minimized subject to lift, pitching moment, geometric constraints, and a 2.5 g maneuver bending moment constraint. The trailing edge of the wing is optimized based on the multipoint optimized wing. The trailing edge morphing is parameterized using 90 design variables that are optimized independently for each flight condition. A total of 407 trailing edge optimizations are performed at different flight conditions to span the entire flight envelope. We observed 1% drag reduction at on-design conditions, and 5% drag reduction near off-design conditions. The effectiveness of the trailing edge morphing is demonstrated by comparing it with the optimized results of a hypothetical fully morphing wing. In addition, we compute the fuel-burn reductions for a number of flights using the optimization results. A 1% cruise fuel-burn reduction is achieved using an adaptive morphing trailing edge for a typical long-haul twin-aisle mission.