Evaluation of Aeroelastic Coupling between a Shock Boundary Layer Interaction and Compliant Surface*

An inadequate understanding of the role of inherently unsteady flow features in interactions between lightweight aircraft structures and turbulent flows impedes rapid and accurate computational aeroelastic analysis. In this work, a large-eddy simulation flow solver is coupled to a finite element structural solver to investigate the interaction and coupling mechanisms between an impinging shock boundary layer interaction (SBLI) and a compliant surface. The large separation region associated with the strong SBLI subjects the compliant surface to a wide range of turbulent fluctuations, which complicate the task of identifying and classifying aeroelastic responses with significant levels of coupling. Of particular interest is the possibility for static and dynamic feedback from the structure to the inherent flow unsteadiness. To elucidate the potential alteration of the intrinsic flow unsteadiness and to distinguish between the mean flow, structurally induced flow, and background fluctuations, a triple decomposition of the flow is adopted. Careful analysis of the coupled structural response allows for subsequent fluid-only simulations that harmonically force the flow through prescribed structural motions. Thus, an exact extraction of a representative induced flow response is obtained. Analysis of the remaining turbulent fluctuations allows for key insights into the predominant coupling mechanisms that must be considered when performing reduced-order aeroelastic computations.