周期节流扰动下激波串振荡流动的数值模拟

基于动网格方法数值模拟并分析来流马赫数为6，二元进气道/隔离段构型在频率为50～500 Hz周期节流下的激波串振荡流动。结果表明：当节流比在0.2～0.32范围内周期变化时，隔离段出现与节流频率相同的激波串振荡现象。节流频率会影响激波串振荡幅度和壁面压强波动特性。50 Hz与100 Hz工况的激波串流向振幅相近，100～500 Hz范围内随频率增加，流向振幅从15.5 mm减小至10.8 mm。壁面压强随频率的变化规律更加复杂，以凹腔中部为界，其上游壁面压强时均值、均方差峰值整体随频率增加而降低，其中50 Hz工况唇口侧壁面压强均方差峰值可达21倍来流静压，但其下游壁面压强无明显规律。分析表明节流频率对激波串振荡的影响与节流扰动的传播时间相关，工程设计中需综合考虑构型与反压参数对激波串振荡的影响。

Numerical simulation of shock train oscillation flows caused by periodic throttle disturbances

Based on the dynamic mesh method, the shock train oscillation flows of a two-dimensional inlet/isolator configuration caused by periodical throttle at frequencies from 50 to 500 Hz were investigated through numerical simulations under Mach number 6 freestream. The results showed that evident shock train oscillations appeared as the throttling ratio varied periodically within the range of (0.2?0.32), and the oscillation frequency accorded with the throttling disturbance frequency. The throttling frequency evidently affected the oscillation amplitude of the shock train and the characteristics of the wall pressure fluctuation. The oscillation ranges of shock train decreased with the increase of throttling frequency higher than or equal to 100 Hz, despite of the similar values between 50 Hz and 100 Hz conditions. The streamwise oscillation range was 15.5 mm and 10.8 mm under 100 Hz and 500 Hz conditions, respectively. Variation law of wall pressure with throttling frequency was complex. Time-averaged magnitudes and mean square deviations of the wall pressures decreased as the throttling frequency increased for the upstream section of the central part of cavity, while the variation laws of wall pressure were ambiguous for the downstream section. The highest square mean deviation was 21 times the freestream static pressure for the cowl sidewall pressure under 50 Hz condition. The analyses showed that variations of shock train oscillation with frequency were related to the response time of inlet/isolator flows to throttle disturbances. It is necessary to comprehensively consider the influences of configurations and back pressure parameters on shock train oscillation in engineering design.