Data-Driven Unsteady Aerodynamic Modeling for Transient Blade Response Prediction*

Aircraft intermittent combustion engines often incorporate turbochargers adapted from ground-based applications to improve their efficiency and performance. These turbochargers operate at off-design conditions and experience high-cycle fatigue brought on by aerodynamically-induced blade resonances. A reduced-order model of the aeroelastic response of general fluid-structural configurations is developed using the Euler-Lagrange equation informed by numerical data from uncoupled computational fluid dynamic (CFD) and computational structural dynamic (CSD) calculations. The structural response is derived from a method of assumed-modes approach. The unsteady fluid response is described by a modified version of piston theory augmented with an inhomogeneous source term developed utilizing data-driven methods. The reduced-order model is applied to a classical panel flutter scenario as well as a more complex turbocharger turbine wheel configuration. The capability of the reduced-order model to predict the presence of flutter in both scenarios from a subset of the uncoupled numerical simulation data is presented, including a critical discussion of the accuracy and validity of piston theory in this context.