Efficient aero-dynamic reduced-order-model based on SCI/ERA method

The Walsh-single-composite-input signals based on orthogonal Walsh function were simultaneously inputted into the CFD(Computational Fluid Dynamics) model, using SCI/ERA(Single-Composite-Input/Eigensystem Realization Algorithm) to identify a discrete-time-domain, unsteady aero-dynamic reduced-order-model(ROM) in state space formulation from CFD responses directly. The Isogai wing stand aeroelastic example was computed, and the results demonstrate that the SCI/ERA method decreases model's dimension in 2 orders while still maintains the same accuracy of unsteady CFD codes. Compared to Pulse/ERA method, it improves the computational efficiency by 24% and saves memory space by 34%. Besides, the SCI/ERA method needs much less additional computational resources than Pulse/ERA method while increasing the coupled structure modes. The frequency-domain BPOD(Balanced Proper Orthogonal Decomposition) method can extract a low frequency second-reduced-order-model(SROM) from ROM while remains the same accuracy. The dimension of ROM further decreases by 88% after second order reduction.