俯仰振荡引起的二元高超声速进气道不起动/再起动特性

Unsteady start/unstart characteristics of 2-D hypersonic inlet caused by oscillating angle-of-attack

关键词:  高超声速进气道  攻角  非定常  不起动  数值仿真

Key words:  Hypersonic inlet  Angle-of-attack  Unsteady  Unstart  Numerical simulation

摘要:

针对高超声速飞行器受到扰动后俯仰姿态可能会瞬时大幅度改变或振荡的问题,为了分析其对进气道起动/不起动特性的影响,在Ma=4.03条件下对二元高超声速进气道俯仰振荡的流场进行了非定常数值模拟研究。研究结果表明:大幅度俯仰振荡的二元高超声速进气道会出现不起动和再起动现象,进入不起动/再起动状态时的流场特征和性能参数均发生剧烈变化;不同折合频率俯仰动态变化时,进气道的性能参数及流场特征存在明显差异,气动性能存在迟滞现象;折合频率越大,进气道发生不起动时的攻角值越大,再起动时的攻角值越小;折合频率增加到一定程度时,进气道可能出现全程起动或不起动现象,初始攻角将是决定进气道处于全程起动或不起动状态的关键因素。

Abstract:

For hypersonic vehicle pitching attitude could be altered notably or forced to oscillating by various perturbations.Unsteady numerical simulations were performed on 2-D hypersonic inlet at Ma 4.03.Effects of dynamic angle-of-attack on start/unstart characteristic were analyzed.The investigation suggests that 2D hypersonic inlet will unstart/restart when the pitching attitude alters notably,Then the characteristic and performance of inlet can be significantly changed.For different reduced frequencies,characteristics of flow field and performances of inlet are different.Unsteady flow field feature and the performance lagbehind.The value of unstart angle-of-attack increases and restart value decreases with the rising of reduced frequencies.It is predicted that when the reduced frequency reaches a critical value,depending on the initial angle-of-attack,the inlet will keep start/unstart in whole circle.