Recent Advances in Reduced-Order Modeling and Application to Nonlinear Computational Aeroelasticity

Reduced-order models (ROMs) are usually thought of as computationally inexpensive mathematical representations that oer the potential for near real-time analysis. Indeed, most ROMs can operate in near real-time. However, their construction can be computationally intensive as it requires accumulating a large number of system responses to input excitations. Furthermore, ROMs usually lack robustness with respect to parameter changes and therefore must often be rebuilt for each parameter variation. Together, these two issues underline the need for a fast and robust method for adapting pre-computed ROMs to new sets of physical or modeling parameters. To this eect, this paper reports on recent advances in this topic. In particular, it describes a recently developed interpolation method based on the Grassmann manifold and its tangent space at a point that is applicable to structural, aerodynamic, aeroelastic and many other ROMs based on projection schemes. This method is illustrated here with the adaptation of CFD-based aeroelastic ROMs of complete fighter configurations to new values of the free-stream Mach number. Good correlations with results obtained from direct ROM reconstruction and high-fidelity linear and nonlinear simulations are reported, thereby highlighting the potential of the described ROM adaptation method for near real-time aeroelastic predictions using pre-computed ROM databases.