跨音叶栅非定流场数值模拟

NUMERICAL SIMULATION OF UNST EADY FLOW IN A TRANSONIC CASCADE

本文将二维平面振荡叶栅的非定常流场分解为定常平均流场和以简谐振荡为运动规律的非定常小扰动的叠加 ,分别求解定常的 N- S方程和非定常线化 N- S方程 ,能对不同分离形式进行数值模拟 ,有效地处理分离流动。计算结果表明 ,非定常分离、粘性效应和跨音激波对叶栅气动弹性稳定性有极其重要的影响 ,并且说明分离区内的脉动压力对叶栅振荡的响应只比分离区外低一个数量级 ,因而在处理非定常分离流动时不能简单地将分离区内的压力脉动视为零。

The effects of unsteady separation,shock and viscosity on the stall flutter become now a main obstacle to aeroelastic study.The 2 D unsteady flow in an oscillating cascade is taken as composed of two parts:the steady mean flow and the small disturbance flow.The stall flutter is predicted by solving the steady Navier-Stokes equations and linearized Navier-Stokes equations separatedly,and can be simulated numerically for different kinds of flow separation,and then the unsteady separation can be treated effectively.The calculation results show that unsteady separation,shock and viscosity have significant effects on the stall flutter.Therefore,the unsteady pressure response in the separated zone cannot be taken as zero.