Development of Transonic Unsteady Aerodynamic Reduced-Order Models Using System Identification Techniques

TL;DR

This paper presents a novel reduced-order modeling approach for unsteady transonic aerodynamics using system identification, enabling efficient aeroelastic analysis in the frequency domain.

Contribution

It introduces a system identification-based method to develop reduced-order models for transonic unsteady aerodynamics, integrating CFD data and mode decomposition.

Findings

Effective modeling of unsteady aerodynamic loads in transonic regime.

Demonstrated the importance of signal processing in transfer function computation.

Validated the reduced-order models for aeroelastic analysis of a NACA 0012 airfoil.

Abstract

The present paper develops a reduced-order model capable of modeling unsteady aerodynamic loads in the transonic regime using system identification techniques. The computational fluid dynamics (CFD) calculations are based on the Euler equations and the code uses a finite volume formulation for general unstructured grids. A centered spatial discretization with added artificial dissipation is used, and an explicit Runge-Kutta time marching method is employed. For comparison reasons, unsteady calculations are performed using mode-by-mode and simultaneous excitation approaches. System identification techniques are employed to allow the splitting of the aerodynamic coefficient time histories into the contribution of each individual mode to the corresponding aerodynamic transfer function. Such methodology is applied to model the aerodynamic terms of the aeroelastic state-space system particularly of a NACA 0012 airfoil-based typical section. Results demonstrate the importance of signal processing techniques to compute the aerodynamic transfer functions and also the advantageous applicability of transonic unsteady aerodynamic reduced-order models to perform aeroelastic analyses in the frequency domain.