REDUCED-ORDER MODELS OF UNSTEADY TRANSONIC VISCOUS FLOWS IN TURBOMACHINERY

• Published in: Journal of fluids and structures Vol. 14; no. 8; pp. 1215 - 1234
• Main Authors: EPUREANU, B.I., DOWELL, E.H., HALL, K.C.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01-11-2000; Elsevier
• Subjects: Applied sciences; Compressible flows; shock and detonation phenomena; Continuous cycle engines: steam and gas turbines, jet engines; Engines and turbines; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Mechanical engineering. Machine design; Physics; Transonic flow; Blades; Computational fluid dynamics; Oscillating aerofoil; Steady flow; Theoretical study; Eigenfunctions; Turbomachinery; Orthogonal polynomial; Potential flow; Transonic velocity; Orthogonal function; Viscous fluids; Boundary layers; Viscous flow
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1006/jfls.2000.0320

The proper orthogonal decomposition (POD) technique is applied in the frequency domain to obtain a reduced-order model of the unsteady flow in a transonic turbomachinery cascade of oscillating blades. The flow is described by a inviscid—viscous model, i.e. a full potential equation outer flow model and an integral equation boundary layer model. The nonlinear transonic steady flow is computed first and then the unsteady flow is determined by a small perturbation linearization about the nonlinear steady solution. Solutions are determined for a full range of frequencies and validated. The full model results and the POD method are used to construct a reduced-order model in the frequency domain. A cascade of airfoils forming the Tenth Standard Configuration is investigated to show that the reduced-order model with only 15–75 degrees of freedom accurately predicts the unsteady response of the full system with approximately 15 000 degrees of freedom.