This paper describes the work performed by ONERA and Airbus to solve several aerodynamic optimization problems proposed in 2013 by the AIAA Optimization Discussion Group (ADODG). Three of the four test cases defined by this group have been addressed, respectively a 2D invicid, non-lifting, transonic airfoil optimization problem, a 2D RANS transonic airfoil optimization problem and a 3D RANS transonic wing optimization problem. All three problems have been investigated using local, gradient-based, optimization techniques and the elsA[1][2] CFD software and its adjoint capability. Through these three optimization exercises, several generic issues introduced by aerodynamic gradient-based optimization have been investigated. Among the investigated aspects are the impact of the geometry parameterization (nature and dimension), of the accuracy of the gradient calculation method, optimization algorithm and presence of constraints in the optimization problem. NomenclatureC p = pressure coefficient CD = total drag coefficient CDp = pressure drag coefficient CDf = friction drag coefficient CDw = wave drag coefficient CDvp = viscous pressure drag coefficient CL = lift coefficient CM = pitching moment coefficient c ref = chord reference d.c. = drag counts (0.0001) Ma = Mach number Re = Reynolds number AoA = Angle of attack f = objective function g = inequality constraint 1

No abstract

In the present work, the CFD analysis and local shape optimization of a boxwing architecture designed during the early stages of the PARSIFAL project are addressed in order to assess and improve its transonic aerodynamic performance. The assessment of the baseline configuration is carried out by means of highfidelity RANS computations while an Euler-based workflow is employed for the optimization study. In both cases, CFD computations are supplemented by a far-field drag post-processing to inspect the behavior and the impact of the different drag sources (induced, wave, pressure and viscous dissipation) on the aerodynamic performance. Results obtained from the optimization of local twist and camber parameters for the isolated boxwing lifting-system are presented and discussed. The optimization successfully achieves a great reduction of the compressibility effects affecting the baseline configuration, leading to a substantial improvement of the aerodynamic performance at cruise and higher values of the lift coefficient.

No abstract

No abstract

This paper aims at presenting aerodynamic optimizations carried out at Onera in collaboration with Airbus on the AVECA flying wing configuration using the adjoint approach. Several optimizations were conducted in order to define an optimization scenario to maximize the aerodynamic performance of the AVECA configuration in cruise conditions under geometric and aerodynamic constraints at fixed wing planform. This scenario was then applied to several wing planforms in order to define the influence of the re-optimization to compute the sensitivities of the aerodynamic performance to several wing planform parameters. Finally, a cruise optimization was conducted taking into account a low-speed constraint (Take-off rotational criterion) in order to define a viable flying wing configuration at cruise but also in low-speed conditions. Nomenclature= centre of pressure location y = wing span direction  = vector of parameters X = vector of mesh coordinates W = aerodynamic field  t = turbulent eddy-viscosity LS = low-speed HS = high-speed

This paper describes the work performed by Onera on disruptive aircraft architectures in the frame of the Clean Sky2 -ITD Airframe European project. This paper details first the Overall Aircraft Design process set-up to evaluate the performance of four innovative concepts (lifting fuselage, 3-surfaces, joined-wing and Blended Wing Body configurations) on two specific missions (A320-like and businesslike). To improve the accuracy of the process and integrate more refined physical models, high-fidelity tools were introduced in the process for aerodynamics (CFD Euler computations) and structure (Finite Element Model). As far as propulsion aspects are concerned, a specific module was developed in order take into account the thermodynamic effects in the process and resize the engine at each step of the process. Regarding handling qualities a generic module was developed in order to take into account certification criteria early in the design process. For the acoustic and aeroelastic aspects, supplementary analysis methods are proposed in order to quantify the noise reduction benefits from the source modifications and shielding effects by these geometries and potential aero-elastic issues.

No abstract