Projection Framework for Interfacial Treatment for Computational Fluid Dynamics/Computational Structural Dynamics Simulations

This paper presents a physics-based projection framework for the interfacial treatment of spatially and topologically different grids. The formulation proposes the use of constraint type elements, commonly used in finite element analysis, to establish the projection matrix. Through a series of verification studies, the proposed method is demonstrated to apply to any underlying finite element type and yields increased accuracy in projecting field values when compared with conventional mathematical-based interpolation approaches, such as radial basis functions (RBFs). The sensitivity of the approach to the number of connection points and the resolution of a computational structural dynamics grid are investigated, and optimal parameters are presented. The framework is demonstrated to be feasible for complex aeroelastic system configurations by using a representative F/A-18 Super Hornet dynamic beam-rod model. The proposed framework suggests a more physically viable transformation of the mode shapes as compared with RBFs without any additional preprocessing that would otherwise be necessary. Investigations of the forced harmonic response of the F/A-18 Super Hornet aeroelastic system showed significant differences in the dynamic response. Flutter results for the scaled model using the proposed approach accurately estimated the altitude. At the same time, RBFs showed a large discrepancy, highlighting the importance of the interfacial treatment for investigations of aeroelastic responses, as well as the assessment of critical dynamic loads.