关键词: 叶片颤振；非定常流；高低空；能量法

Abstract: In order to uncover the effect mechanics of high-low altitude on aeroelasticity stability of compres. sor，blades flutter characteristics in different altitudes were investigated through numerical study based on har.monic balance technique and energy method. Results show that，for the 2nd mode on the near stall point，the mini. mum aerodynamic damping of blades corresponding to nodal diameter has the value of 1 on the ground，while the value of 2 in high altitude. The minimum values of aerodynamic damping coefficient(LogDec)of blades were 0.3460%，0.2168% and 0.5460%，0.4521%，respectively，in high and low altitude for the first two modes on the near stall point，nevertheless，at the blade tip the local LogDec on the ground is less than this in high altitude. Theunsteady pressure perturbations present various time-space shapes with different working altitudes at the bladetip corresponding to the first mode on the near stall point，which results in a huge discrepancy of local work sum. mation.

Key words: Blade flutter；Unsteady flow；High-low altitude；Energy method