The expected computational power that will become available in the next years and decades will allow the introduction of more accurate simulations at earlier aircraft design stages. It is thus mandatory to identify and consequently develop multi-disciplinary optimization capabilities based on high-fidelity methods enabling the design of the future aircraft. The paper will give an overview of the latest development conducted at DLR in this field. Three representative applications will demonstrate benefits and limitations of the capabilities developed. Nomenclature FFD= Free-Form Deformation CD = Drag Coefficient CFD = Computational Fluid dynamics CL = Lift coefficient C SFC = Thrust Specific Fuel Consumption DC = Drag Counts (1DC=0.0001) HTP = Horizontal Tail Plane M  = Cruise Mach Number MTOW = Maximum Take-Off Weight RANS = Reynolds Averaged Navier-Stokes Equations Re = Reynolds Number VTP = Vertical Tail Plane W = Weight

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This paper describes investigations of planform and shape optimizations for a flying wing transport aircraft with an Euler continuous adjoint method. For a prescribed lift the cost function will be the drag, which has to be minimized and implies a maximization of L/D. The results presented for the gradient based method using an adjoint solver are compared to an optimization performed with a gradient free approach. The different workflows and procedures will demonstrate the advantages and disadvantages of each particular optimization approach.The optimization procedure uses a freeform deformation technique for the design parameterization of the shape as well as for the surface mesh deformation required to determine the gradients. This combination of both tasks into one tool is advantageous because performing finite differences for evaluating the mesh sensitivities can be carried out with a constant grid topology. An example design case is also shown for demonstration purposes.

A prerequisite for the prediction of ice accretion on an aircraft flying through clouds of supercooled liquid water is the accurate determination of the water impingement rate on various components of the aircraft. For this purpose, a droplet impingement module has been developed using the datastructure of the unstructured Navier-Stokes solver TAU. Since nowadays large computational grids are common practice, an efficient algorithm for determination of the droplet trajectories on such grids had to be implemented. This paper describes the physics and details of the implemented numerical algorithm. It summarizes lessons learned during development. The paper concludes with the presentation of code validation results and examples of applications.