REDUCED-ORDER MODELS OF UNSTEADY VISCOUS FLOWS IN TURBOMACHINERY USING VISCOUS–INVISCID COUPLING

• Published in: Journal of fluids and structures Vol. 15; no. 2; pp. 255 - 273
• Main Authors: EPUREANU, B.I., HALL, K.C., DOWELL, E.H.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01-02-2001; Elsevier
• Subjects: Computational methods in fluid dynamics; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Physics; Forming processes; Degrees of freedom; Steady flow; Eigenfunctions; Frequency domain method; Boundary integral method; Airfoils; Turbomachinery; Decomposition; Numerical method; Unsteady flow; Experimental study; Orthogonal polynomial; Shell models; Reduction method; Aerofoil cascade; Non viscous fluid; Orthogonal function; Modelling; Coupling; Non linear effect; Viscous fluids; Boundary layers; Viscous flow
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1006/jfls.2000.0334

The proper orthogonal decomposition technique is applied in the frequency domain to obtain a reduced-order model of the flow in a turbomachinery cascade. The flow is described by an inviscid–viscous interaction model where the 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 steady solution. A frequency-domain model is constructed and validated, showing to provide similar results when compared with previous computational and experimental data presented in the literature. The full model is used to obtain a reduced-order model in the frequency domain. A cascade of airfoils forming a slightly modified Tenth Standard Configuration is investigated to show that the reduced-order model with only 25 degrees of freedom accurately predicts the unsteady response of the full system with approximately 10 000 degrees of freedom.