Unsteady Flow Analysis of Vibrating Cascade under Flow/Structure Coupled Condition
Yang Qingzhen,Shi Yongqiang,Xiao Jun,Zhou Xinhai
(School of Dynamics and Energy, Northwestern Polytechnical Univ., Xi'an 710072, China)

Abstract: 2D viscous flow/structure vibration coupled relations are established, and the dual time stepping method is adopted to solve flow/structure coupled unsteady flow, and 2D unsteady viscous flow among cascades and vibration chara cteristics of the cascades are investigated. The flow at different reduced frequ encies is analyzed for two blades. The displacement variation history shows that the forced vibration frequency is lower than free vibration frequency. The disp lacement-time curve of blade surface is quite different between the flow/structure coupled case and free vibration case. The vibration stability and aerodynamic characteristics of flow/structure coupling results are significantly different from those of uncoupling results. It is necessary for cascade vibration stability analysis to take account of structure dynamics factors.
Keyword: vibrating cascade, unsteady flow, flow/structure coupling, moving grid, dualtime.