Reduced-order models of unsteady viscous flows in turbomachinery using viscous-inviscid coupling

The proper orthogonal decomposition technique is applied in the frequency d omain to obtain a reduced-order model of the flow in a turbomachinery casca de. The flow is described by an inviscid-viscous interaction model where th e inviscid part is described by the full potential equation and the viscous part is described by an integral boundary layer model. The fully nonlinear steady flow is computed and the unsteady flow is linearized about the stea dy solution. A frequency-domain model is constructed and validated, showing to provide similar results when compared with previous computational and e xperimental data presented in the literature. The full model is used to obt ain a reduced-order model in the frequency domain. A cascade of airfoils fo rming a slightly modified Tenth Standard Configuration is investigated to s how that the reduced-order model with only 25 degrees of freedom accurately predicts the unsteady response of the full system with approximately 10 00 0 degrees of freedom. (C) 2001 Academic Press.