Flutter analysis of cascades using an Euler/Navier-Stokes solution-adaptive approach

In this study, cascade nutter analyses for inviscid and viscous flows are presented. In the present time-domain approach, the structural model equations for each blade as a typical section having plunging and pitching degrees of freedom are integrated in time by the explicit four-stage Runge-Kutta scheme, A solution-adaptive finite volume method with globally/rigid-deformable dynamic mesh treatments is introduced to solve the two-dimensional Euler/Navier-Stokes equations. For viscous non's, the Boldwin-Lomax turbulence model and two transition formulations are adopted. By comparing with the related data in two inviscid transonic-cascade-nutter problems, the reliability and suitability of the present approach are confirmed. From the time histories of blade displacements and total energy in transonic;flutter calculations, it is observed that the viscous effect has a damping influence on the aeroelastic behavior. The instantaneous meshes and vorticity contours clearly indicate the shack/boundary-layer interaction, large vortex structure, and big plunging motion in the transonic nutter, subsonic stall nutter, and supersonic bending nutter respectively. By using the fast Fourier transformation and modal identification techniques, the aeroelastic behaviors in the inviscid transonic and viscous transonic, subsonic stall, and supersonic bending nutter problems are further investigated.