Publications

Since its introduction the NASA Common Research Model (CRM) has served as a useful aerodynamic benchmark for drag prediction and optimization of various CFD codes. The model was originally conceived as a purely aerodynamic benchmark and as such the geometry of the wing was designed to take the shape of the deflected wing at a 1.0 g flight condition. There has been growing interest in extending this model to aeroelastic studies as well. However, due to its predefined deflection, the model as is isn’t suitable for aeroelastic analysis and design. To address this we define an undeflected Common Research Model (uCRM) which includes the outer mold line (OML) geometry of the undeflected wing and the corresponding internal wing box structure, with the goal of achieving the flying shape of the CRM under nominal flight conditions. The topology of the wing box is designed to be similar to that of a Boeing 777. The jig shape was arrived at through an inverse design procedure where the objective was to minimize the difference between the 1.0 g aerostructurally deflected shape and the CRM. Since the original CRM has an aspect ratio of 9 we refer to this model as the uCRM-9. Since modern transport aircraft are trending toward higher aspect ratio wing designs in an attempt to reduce induced drag, and therefore fuel burn, it was desired to have an additional higher aspect ratio variant of this model, to assess the design potential of new future technologies with. This variant, uCRM-13.5, has a larger aspect ratio of 13.5 and is defined through an aerostructural optimization of the uCRM-9 with considerations for buffet. The goal for both of these models is to define a useful benchmark for aeroelastic wing analysis and design optimization studies.