A time-linearized Navier-Stokes analysis of stall flutter

A computational method for predicting unsteady viscous flow through two-dim ensional cascades accurately and efficiently is presented. The method is in tended to predict the onset of the aeroelastic phenomenon of stall flutter. In stall flutter, viscous effects significantly impact the aeroelastic sta bility of a cascade. in the present effort, the unsteady flow is modeled us ing a time-linearized Navier-Stokes analysis. Thus, the unsteady flow field is decomposed into a nonlinear. spatially varying mean flow plus a small-p erturbation harmonically varying unsteady flow. The resulting equations tha t govern the perturbation flow are linear, variable coefficient partial dif ferential equations. These equations are discretized on a deforming, multib lock, computational mesh and solved using a finite-volume Lax-Wendroff inte gration scheme. Numerical modeling issues relevant to the development of th e unsteady aerodynamic analysis, including turbulence modeling, are discuss ed. Results from the present method are compared to experimental stall flut ter data, and to a nonlinear time-domain Navier-Stokes analysis. The result s presented demonstrate the ability of the present time-linearized analysis to model accurately the unsteady aerodynamics associated with turbomachine ry stall flutter [S0889-504X(00)00203-8].