Eigenmode analysis in unsteady aerodynamics: Reduced order models
A conceptually novel and computationally efficient technique for computing unsteady flow about isolated airfoils, wings, and turbomachinery cascades is presented. A large, sparse eigenvalue problem is solved using the Lanczos algorithm starting with either a time or frequency domain computational fluid dynamics (CFD) analysis of unsteady aerodynamics. Then, using the resulting eigenmodes, a Reduced Order Model of the unsteady flow is constructed. With the model, quick and accurate prediction of unsteady aerodynamic response of the system over a wide range of reduced frequencies can be obtained.